The results of this study indicate that chickpea breeding efforts over the last four decades have made significant progress in improving grain yield and seed size of chickpea varieties in Ethiopia. For the traits measured in this trial, the genetic progress achieved over the years was quite different in the Desi- and Kabuli-type chickpea varieties in the indicated characters.
3.1. Analysis of Variance (ANOVA)
The analysis of variance for individual locations revealed highly significant (p ≤ 0.01) and significant (P ≤ 0.05) differences among the tested Desi- and Kabuli-type chickpea varieties in most of the traits and non-significant effects (p ≥ 0.05) in some of the traits (Table 3). For instance, at Adet station, a highly significant (p ≤ 0.01) effect was observed on seedling stand count (STC), days of 90% physiological maturity (DPM), plant height (PH), plant count at harvest (PCH), hundred seed weight (HSW), biomass yield (BMY),Grain yield (GY) and significant (p ≤ 0.05) differences ondays of 50% flowering (DF), number of primary and secondary branches(NPB, NSB) while non significant effect (p ≥ 0.05) was observed on the number of seed per pod (NSP) and harvest index (HI) due to the main effects of Desi type chickpea varieties. In the outlook of Kabuli type chickpea varieties, a highly significant (p ≤ 0.01) effect was observed on seedling stand count (STC),days of physiological maturity (DPM), plant count at harvest (PCH), hundred seed weight (HSW), biomass and grain yield (BMY,GY) and a significant (p ≤ 0.05) effect was detected on the number of primary and secondary branches (NPB,NSB), number of pod per plant (NPP) and harvest index (HI) whereas a non significant (p ≥ 0.05) effect was observed on days of 50% flowering (DF), number of seed per pod (NSP) and plant height (PH) due to the main effects of the varieties (Table 3). The significant difference between varieties in a similar location might be due to their genetic potential for expressing the indicated traits. This genetic variability seems to be important for thefuture chickpea breeding program, which focuses on phenotypic and molecular descriptions of such genetic resource producing novel and high yielding varieties (Kassahun Amare and Asmamaw Kassahun, 2021).
Moreover at Debre Zeit station, a highly significant (p ≤ 0.01) effect was observed on seedling stand count (STC), days of 50% flowering (DF), days of 90% physiological maturity (DPM), plant count at harvest (PCH), hundred seed weight (HSW), biomass yield (BMY),Grain yield (GY) and significant (p ≤ 0.05) differences on the number of primary branches (NPB) and harvest index (HI) while non significant effect (p ≥ 0.05) was observed on the number of secondary branches, number of pods per plant (NPP) and number of seeds per pod (NSP) due to the main effects of Desi type chickpea varieties. Similarly, a highly significant (p ≤ 0.01) effect was observed on seedling stand count (STC), days of 50% flowering (DF), number of primary branches per plant (NPB), plant count at harvest (PCH), biomass yield (BMY), hundred seed weight (HSW), and a significant (p ≤ 0.05) effect was observed on days with 90% physiological maturity (DPM), number of secondary branches per plant (NSB), number of pods per plant (NPP), and grain yield (GY), while a non significant (p ≥ 0.05) effect was observed on the number of seeds per pod (NSP) and plant height (PH) due to the main effects of Kabuli type chickpea varieties (Table 3). The significance between varieties in a similar location might be due to their genetic potential for expressing the indicated traits because gene expression needs favorable conditions even in the microenvironment. This agreement was in line with Yasin Goa et al. (2017) who found that chickpea varieties were highly significantly differed in biomass and grain yield per plant.
The combined analysis of variance across the two locations also showed highly significant effects of location, variety, and variety × location interaction in most of the traits and non-significant effects (p ≥ 0.05) in some of the traits studied (Table 3). In the Desi, type chickpea varieties a highly significant (p ≤ 0.01) difference was observed on seedling stand count (STC), days of 50% flowering (DF) and grain yield (GY) due to the main effects of variety, location and their interaction parallel. In addition to that, a highly significant (p ≤ 0.01) effect was observed on days of 90% physiological maturity (DPM) and plant height (PH) due to the main effects of variety and location and a significant (p ≤ 0.05) effect was observed due to the interactions. Furthermore, there was a non significant effect on number of primary and secondary branches (NPB,NSB), number of pods per plant (NPP), number of seeds per pod (NSP), plant count at harvest (PCH), hundred seed weight (HSW),biomass yield (BMY) and harvest index (HI) due to the interaction of Desi type chickpea varieties with location (Table 3). Similar trends were observed by Getachew Telahun et al. (2015) who reported that the combined analysis of variance (ANOVA) for yield and yield related traits of different Desi type chickpea varieties showed highly significant difference (p ≤ 0.01) for the main effects of varieties, locations and their interactions, the significant interactions showed varieties response differently across the different locations. Besides that, a highly significant (p ≤ 0.01) difference was observed on seedling stand count (STC), days of 50% flowering (DF), plant count at harvest (PCH), biomass yield (BMY) and hundred seed weight (HSW) due to the main effects of variety, location and their interaction parallel. In addition to that, a highly significant (p ≤ 0.01) effect was observed on grain yield (GY) due to the main effects of Kabuli type chickpea varieties and their interactions while a non significant (p ≥ 0.05) effect was observed on days of 90% physiological maturity (DPM), number of primary and secondary branches (NPB,NSB), number of pods per plant (NPP) and number of seeds per pod (NSP), and plant height (PH) due to the interaction of variety with location (Table 3). Similarly, Genet Mengistu et al. (2020) and Tibebu Belete et al. (2017) reported highly significant (p ≤ 0.01) and significant (p ≤ 0.05) interaction effects on grain yield and other related traits in the Kabuli and Desi type chickpea varieties, respectively.Yasin Goa and Ashamo (2016) and Yasin Goa (2017) also found a significant difference in grain yield and its related components among varieties across different locations in Ethiopia.
Table 3
Mean squares from separate and combined analysis of variance for grain yield and other traits of Desi and Kabuli type chickpea
| Mean squares (MS) at each locations | Mean squares (MS) at combined over locations |
Desi type | Adet | Debre Zeit | Rep (2) | Var (12) | Loc (1) | Var x Loc (12) | Error (50) | Mean | CV | R2 |
Parameters | Var (12) | Error (24) | Var(12) | Error (24) |
STC | 150.6** | 35.42 | 968.36*** | 17.36 | 14.78ns | 913.5*** | 1736.2*** | 205.4*** | 29.34 | 66.03 | 8.2 | 0.91 |
DF | 17.6*** | 3.00 | 76.21*** | 5.25 | 0.81ns | 45.7*** | 1579.5*** | 48.1*** | 4.14 | 57.1 | 3.6 | 0.93 |
DPM | 110.0*** | 12.17 | 156.72*** | 16.14 | 10.6ns | 228.9*** | 19050.8*** | 37.8* | 17.6 | 109.2 | 3.8 | 0.96 |
NPB | 2.18* | 0.84 | 1.27** | 0.35 | 0.6763ns | 3.1*** | 0.046ns | 0.323ns | 0.581 | 4.35 | 17.5 | 0.59 |
NSB | 39.16* | 13.27 | 552.6ns | 303.8 | 2283*** | 399ns | 33476*** | 192ns | 245 | 37.5 | 41.8 | 0.79 |
NPP | 447.64ns | 740.37 | 1745.7ns | 849.4 | 7122.4** | 1197.1ns | 1566.9ns | 996.3ns | 1002.1 | 78.8 | 40.2 | 0.46 |
NSP | 0.18** | 0.045 | 0.33ns | 0.27 | 0.2527** | 0.2647ns | 1.666** | 0.256ns | 0.1506 | 1.70 | 22.8 | 0.53 |
PH (cm) | 176.57*** | 8.29 | 39.51ns | 32.89 | 18.8ns | 168.2*** | 6294.6*** | 47.9* | 21.6 | 43.1 | 10.8 | 0.89 |
PCH | 24.16*** | 1.20 | 57.64*** | 9.54 | 7.65ns | 72.23*** | 90.46*** | 9.57ns | 5.60 | 33.54 | 7.05 | 0.79 |
HSW(gm) | 88.79*** | 12.61 | 96.27*** | 3.47 | 2.167ns | 170.4*** | 24.8ns | 14.68ns | 7.87 | 22.18 | 12.6 | 0.85 |
BMY(Kg/ha) | 4360*** | 1559 | 5425*** | 3588 | 16339ns | 9332*** | 151040* | 45286ns | 250767 | 4672.8 | 10.7 | 0.91 |
GY(Kg/ha) | 7792*** | 2472 | 13263*** | 6639 | 119200ns | 1949*** | 431305*** | 15664*** | 57281 | 2246.5 | 10.7 | 0.91 |
HI (%) | 0.0035ns | 0.0018 | 0.0049* | 0.002 | 0.00504ns | 0.0056* | 0.10708*** | 0.00293ns | 0.0024 | 0.48 | 10.3 | 0.64 |
Kabuli type | Var (14) | Error (28) | Var (14) | Error (28) | Rep (2) | Var (14) | Loc (1) | Var x Loc (14) | Error (58) | Mean | CV | R2 |
STC | 63.12*** | 5.927 | 506.78*** | 8.17 | 26.43* | 330.5*** | 1314.9*** | 239.44*** | 6.93 | 66.13 | 3.98 | 0.96 |
DF | 10.13ns | 7.01 | 59.75*** | 5.73 | 50.54*** | 48.09*** | 1690.0*** | 21.79*** | 6.43 | 58.56 | 4.33 | 0.88 |
DPM | 188.12*** | 29.08 | 258.33* | 101.15 | 9.7ns | 365.3*** | 21068.1*** | 81.2ns | 66.1 | 113.8 | 7.14 | 0.88 |
NPB | 1.2038** | 0.3284 | 0.712*** | 0.1373 | 2.626*** | 1.753*** | 0.2668ns | 0.1627ns | 0.2433 | 3.92 | 12.6 | 0.69 |
NSB | 10.59** | 3.670 | 288.77* | 136.06 | 779.6*** | 175.2* | 21607.0*** | 124.1ns | 90.3 | 29.81 | 31.9 | 0.84 |
NPP | 202.85* | 76.16 | 535.89* | 225.43 | 1561.5** | 523.55** | 798.64* | 215.19ns | 180.02 | 55.12 | 24.3 | 0.58 |
NSP | 0.08889ns | 0.0685 | 1.198ns | 1.506 | 1.705ns | 0.527ns | 38.16*** | 0.760ns | 0.786 | 1.87 | 47.3 | 0.57 |
PH (cm) | 82.852ns | 67.55 | 43.078ns | 27.55 | 61.2ns | 68.3ns | 9494.6*** | 57.6ns | 47.7 | 46.93 | 14.7 | 0.81 |
PCH | 31.28*** | 1.83 | 52.33*** | 4.37 | 3.61ns | 37.64*** | 60.84*** | 45.96*** | 3.12 | 32.3 | 5.5 | 0.87 |
HSW(gm) | 249.89*** | 19.03 | 89.21*** | 1.85 | 7.23ns | 227.7*** | 567.51*** | 111.37*** | 10.18 | 30.6 | 10.4 | 0.90 |
BMY(Kg/ha) | 12137*** | 8368 | 349645*** | 4700 | 13210ns | 3093*** | 78438*** | 16169*** | 28072 | 5471.4 | 9.7 | 0.82 |
GY(Kg/ha) | 5170*** | 3689 | 903330** | 245703 | 6434ns | 7828*** | 5180ns | 6375*** | 1384 | 2476.9 | 15.0 | 0.71 |
HI (%) | 0.00322* | 0.001451 | 0.002487ns | 0.002132 | 0.00002ns | 0.0018ns | 0.0588*** | 0.00391* | 0.0018 | 0.45 | 9.3 | 0.58 |
Rep = replication, Loc = location, Var = Variety, STC = seedling stand count, DF = Days of flowering, DPM = Days of physiological maturity, NPB = number of primary branches, NSB = number of secondary branches, NPP = number of pod per plant, NSP = number of seed per pod, PH = plant height, PCH = plant count at harvest, GY = grain yield, BMY = biomass yield and HI = harvest index. ns = non significant, ***=highly significant, ** or * significant at 0.01 and 0.05.
3.2. Grain Yield Potential
The grain yield performance of all Desi type chickpea varieties averaged over locations were 2246.5 kgha− 1, which ranged from 878.5 kg ha− 1 for the variety Mariye to 3029.9 kg ha− 1 for the variety Teketay (Table 4). The Mariye variety, which was released in 1985, showed a lower grain yield than all varieties used in this trial. The variety Teketay, which was released in 2013, had the highest yield among the tested Desi-type chickpea varieties. The recently released varieties Natoli (2782.5 kgha1) and Dalota (2697.2Kgha1) had the second best yields among the varieties next to Teketay (Table 4). The poor relative yield of Mariye in this study may be due to its lower plant count at harvest, which strongly determines the biomass yield (Table 4) and likely affects the grain yield.This result might be nearly explained with Tibebu Belete et al. (2017) who reported that, the average grain yield of all Desi type chickpea varieties was 2003.48 kgha− 1, which ranged from 1589.70 kg ha− 1 for the variety released in 1974 (DZ-10-11) to 2303.30 kgha− 1 for the variety released in 2007 (Natoli). Omar et al. (2019) also reported that the yield advantage of improved varieties over local check increased from 16 to 67% from 1989 to 2018 in Morocco.
Similarly, the grain yield performance of all Kabuli type chickpea varieties averaged over locations was 2476.9 kgha− 1, which ranged from 1847.9 kgha− 1 for the variety Teji to 2964.6 kgha− 1 for the variety Koka (Table 4). The variety Teji released in 2005 showed a lower grain yield than all varieties used in this trial. The variety Koka, which was released in 2019, and the variety Chefe (2975.7Kgha− 1) which was released in 2004, were the highest yielding varieties among the tested Kabuli-type chickpea varieties. The recently released Kabuli-type chickpea varieties, such as Hora and Dhera, were the second-best yielder among the varieties, followed by Koka (Table 4). The poor relative yield of Teji in this study may be due to its lower mean number of seeds per pod, which strongly determines grain yield (Table 4). Megersa Tadesse et al. (2018) found that the mean values for grain yield in Kabuli-type chickpea varieties ranged from 1900 to 3400 kg/ha, with an average yield of 2650 kg/ha. However, Deresa Shumi et al (2017) revealed that, from the overall mean grain yield of Kabuli-type chickpeas, the highest mean value of grain yield was from the variety Habru (1822 kg/ha), while the lowest was from the variety Ejere (1264 kg/ha). This indicates that all the varieties have been performed differently across the different locations because of the variation in the environment and genetic makeup could be the possible reason for the observed differences (Yasin Goa et al., 2017).
Table 4
Mean Values of Different Traits from Combined Analysis of Variance for Desi and Kabuli type chickpea Varieties
Desi type | Parameters | |
STC | DF | DPM | NPB | NSB | NPP | NSP | PH (cm) | PCH | BMY (Kg/ha) | HSW (gm) | GY (Kg/ha) | HI (%) |
DZ-10-11 | 49.2e | 59.0b | 106.5bc | 4.1bcd | 50.3abc | 102.9ab | 1.6abc | 37.4f | 28.5fg | 3074.9e | 12.3e | 1606.2g | 0.53a |
Mariye | 43.7ef | 58.7bc | 123.5a | 5.9a | 55.9a | 105.1a | 1.6bc | 39.1def | 27.5g | 1772.2f | 21.8c | 878.5h | 0.49ab |
Akaki | 42.8f | 58.2bc | 108.0bc | 4.8b | 38.0abc | 84.6abc | 2.1a | 42.8cde | 30.7ef | 3858.3d | 19.0cd | 2023.6ef | 0.51ab |
Kutaye | 68.7bcd | 54.8d | 106.3bc | 4.4b | 38.2abc | 75.4abc | 1.8abc | 40.2def | 33.3cde | 4574.9c | 19.3cd | 2195.2de | 0.48abc |
Mastewal | 70.2bcd | 59.2b | 106.2bc | 4.3bc | 34.5bc | 64.9c | 1.6abc | 40.8def | 32.8de | 5229.5b | 20.7c | 2168.1de | 0.42d |
Fetenech | 68.0cd | 54.5d | 109.0b | 3.3d | 35.8bc | 82.3abc | 1.6abc | 38.9ef | 30.0fg | 3622.7de | 19.8c | 1862.2fg | 0.52ab |
Natoli | 76.7a | 60.0b | 103.3c | 4.2bc | 31.9c | 80.4abc | 1.9ab | 40.2def | 37.5a | 5613.9ab | 27.0ab | 2782.5ab | 0.49abc |
Minjar | 67.3d | 54.3d | 108.2bc | 4.8b | 40.9abc | 81.5abc | 2.1a | 46.7bc | 34.2bcd | 5041.7bc | 19.5cd | 2407.6cd | 0.48abc |
Teketay | 77.3a | 55.5d | 107.2bc | 4.7b | 27.7c | 62.1c | 1.5bc | 49.3b | 38.3a | 6108.5a | 26.8ab | 3029.9a | 0.49ab |
Dalota | 73.8abc | 56.3cd | 107.7bc | 3.5cd | 30.7c | 76.9abc | 1.7abc | 44.3bcd | 36.2ab | 5580.6ab | 25.5b | 2697.2b | 0.49abc |
Dimtu | 72.3abcd | 55.0d | 107.3bc | 4.2bcd | 31.2c | 58.4c | 1.6bc | 40.3def | 34.7bcd | 5316.7b | 30.0a | 2319.4d | 0.44cd |
Geletu | 73.5abcd | 54.0d | 105.5bc | 3.5cd | 30.8c | 66.7bc | 1.3c | 43.4cde | 35.8abc | 5466.7b | 30.0a | 2627.8bc | 0.46bcd |
Eshete | 74.8ab | 63.0a | 122.2a | 4.9b | 40.6abc | 83.4abc | 1.7abc | 56.8a | 36.5ab | 5486.1b | 16.5d | 2606.3bc | 0.47bcd |
Mean | 66.03 | 57.1 | 109.2 | 4.35 | 37.5 | 78.8 | 1.70 | 43.1 | 33.54 | 4672.8 | 22.18 | 2246.5 | 0.48 |
CV | 8.2 | 3.6 | 3.8 | 17.5 | 41.8 | 40.2 | 22.8 | 10.8 | 7.05 | 10.7 | 12.6 | 10.7 | 10.3 |
R2 | 0.91 | 0.93 | 0.96 | 0.59 | 0.79 | 0.46 | 0.53 | 0.89 | 0.79 | 0.91 | 0.85 | 0.91 | 0.64 |
Kabuli type | |
DZ-10-4 | 61.3fg | 56.5de | 108.0efg | 3.6bcd | 40.1a | 76.1a | 1.8a | 43.1c | 27.3h | 4333.3b | 18.8g | 2156.9def | 0.44ab |
Shasho | 70.7bcd | 61.8ab | 112.2defg | 4.2b | 32.0ab | 57.9b | 1.8a | 47.9abc | 33.2cd | 5888.9a | 27.8ef | 2444.4bcd | 0.44ab |
Arerti | 69.2cd | 63.0a | 116.7cde | 4.7a | 34.2ab | 56.9b | 1.7a | 44.7c | 32.3cde | 5924.5a | 26.0f | 2723.0ab | 0.45ab |
Habru | 71.3abc | 61.3ab | 114.7cdef | 4.7a | 26.5bc | 51.6b | 1.5a | 45.0c | 33.8bc | 5905.6a | 25.7f | 2756.3ab | 0.46ab |
Chefe | 74.3a | 54.8e | 105.8fg | 3.8bc | 24.9bc | 49.4b | 1.9a | 48.5abc | 35.8ab | 6088.9a | 32.2bc | 2975.7a | 0.48a |
Teji | 59.3g | 56.2e | 114.8cdef | 3.1de | 25.9bc | 54.8b | 1.3a | 43.8c | 33.3cd | 4291.6b | 29.8cde | 1847.9f | 0.44ab |
Ejeri | 71.0bc | 56.3e | 108.8efg | 4.1bc | 25.6bc | 50.9b | 2.2a | 46.5bc | 33.3cd | 6093.6a | 28.2def | 2615.3abc | 0.47ab |
Yelbie | 62.8f | 55.7e | 106.2fg | 4.0bc | 33.4ab | 58.9b | 1.7a | 43.3c | 28.5gh | 4636.1b | 30.2cde | 1981.9ef | 0.43ab |
Acos Dubie | 52.7h | 60.0bc | 111.2defg | 3.0e | 16.9c | 31.9c | 2.1a | 53.7ab | 29.5fg | 5875.0a | 48.0a | 2781.9ab | 0.48a |
Kasech | 66.0e | 57.2cde | 104.7g | 3.6cde | 33.2ab | 58.8b | 2.3a | 48.2abc | 30.8ef | 5766.7a | 29.8cde | 2611.8abc | 0.46ab |
Akuri | 67.8de | 56.5de | 119.0bcd | 3.8bc | 31.2ab | 59.2b | 1.6a | 45.6c | 32.8cde | 4694.5b | 32.3bc | 2237.5cdef | 0.44ab |
Kobo | 50.3h | 59.3bcd | 126.2ab | 3.6bcd | 33.4ab | 63.6ab | 1.7a | 45.8bc | 31.5def | 4611.1b | 31.7bcd | 1994.5ef | 0.46ab |
Hora | 73.2ab | 62.0ab | 123.7abc | 4.1bc | 29.9ab | 49.8b | 2.1a | 46.9abc | 33.8bc | 5873.0a | 30.7cde | 2655.5abc | 0.44ab |
Dhera | 68.5cde | 61.7ab | 129.0a | 4.7a | 28.6b | 50.7b | 2.0a | 54.6a | 32.0cde | 5838.9a | 33.2bc | 2405.6bcde | 0.42b |
Koka | 73.5ab | 56.0e | 106.0fg | 3.8bc | 31.3ab | 56.4b | 2.3a | 46.2bc | 36.5a | 6250.0a | 34.7b | 2964.6a | 0.48a |
Mean | 66.13 | 58.56 | 113.8 | 3.92 | 29.81 | 55.12 | 1.87 | 46.93 | 32.3 | 5471.4 | 30.6 | 2476.9 | 0.45 |
CV | 3.98 | 4.33 | 7.14 | 12.6 | 31.9 | 24.3 | 47.3 | 14.7 | 5.5 | 9.7 | 10.4 | 15.0 | 9.3 |
R2 | 0.96 | 0.88 | 0.88 | 0.69 | 0.84 | 0.58 | 0.57 | 0.81 | 0.87 | 0.82 | 0.90 | 9.3 | 0.58 |
LSD = list significant difference, Means with the same letter in same column are not significantly different and vice versa |
3.3. Genetic Gain for Grain Yield and Other Related Traits
3.3.1. Grain yield (GY)
Breeding progress is a measure of the increase in the offspring’s average genetic value for a specific trait compared to the whole population of the previous generation’s average. One of the methods widely used to estimate the progress made from the genetic gain achieved in plant breeding programs is the regression of the average performance of released varieties for a specific trait in different environments over their years of release (Omar et al. 2019). Dagnachew Bekele et al (2014) studied the genetic progress in chickpea, and the absolute genetic progress in grain yield for Desi type chickpea varieties was approximately 32 kg/ha/year (P ≤ 0.001, R2 = 0.725) with a relative genetic progress of 2.13% year1. While, there was a non significant (15.3 kg ha− 1year− 1) (R2 = 0.164) genetic progress for Kabuli types chickpea with respect to grain yield with relative genetic progress of 0.87% year− 1. The absolute genetic progress in terms of 100 seed weight was 0.320 g year1 (R2 = 0.626) for the Desi type, and 0.931g/year (P ≤ 0.001, R2 = 0.764) for Kabuli, with relative genetic progress of 2.58% and 8.62% year1, respectively. In the Desi type chickpea varieties the mean grain yield of varieties released in 1970s,1980s, 1990s and 2000s were1606.2, 878.5, 2023.6 and 2469.62kg/ha (Table 5), respectively. These result indicated that, an increase of -727.7 (-45.3%), 417.4 (25.9%) and 863.42kg/ha (53.7%) over the first released variety (Table 5), individually. The average mean grain yield of varieties released in 2000s better than that of the first released variety in 1974 (DZ-10-11), 1980s and 1990s (Table 5). Hence, grain yield has increased from old to new varieties during the last 46 years of Desi-type chickpea breeding in Ethiopia. This implies that, chickpea breeders have tried a lot of struggle to improve the grain yield potential of Desi type chickpea varieties. Tibebu Belete et al. (2017) also reported similar results. Temesgen et al. (2015) also found a positive relationship (r = 0.48) between mean grain yields and years of varietal release in faba bean.
Interims of the Kabuli type chickpea varieties the mean grain yield of varieties released in 1970s,1990s and 2000s were 2156.9, 2583.7 and 2485.71kg/ha (Table 5), in that order. These result indicated that, an increase of 426.8 (19.8%) and 328.81kg/ha (15.25%) over the first released variety (Table 5), respectively. Thus, grain yield increased substantially with the release of improved varieties. Which indicates that further improvement is possible to improve this trait and it affords clues for chickpea breeders to exploit the grain yield potential and other related traits of the existing Kabuli type chickpea varieties. Megersa Tadesse et al (2018) reported that, the overall increase in grain yield of Kabuli type chickpea varieties over the local variety and it was estimated to be821.1 kg/ha (43.22%) considering all varieties for the last 41 years since 1974 to 2015.Varieties derived from introductions generated an average grain yield of 2299.86kg/ha, and surpassed the varieties developed from local collections by 693.66kg/ha (43.19%) in the Desi type chickpea varieties (Table 6). This indicates that varieties developed from the introduced germplasm are the most important sources of genetic material contributing to the genetic improvement in grain yield over the last 36 years from 1974 to 2010 and the possibility of further improvement using this breeding method (Tibebu Belete et al., 2017). Similarly, in the Kabuli type chickpea varieties derived from introductions gives an average grain yield of 2499.71kg/ha and it is more than the varieties developed from local collections by 342.81kg ha− 1(15.89%). The outcomes of the present study point out that chickpea improvement program that employed selection from introductions take as the most important breeding methods in improving the grain yield potential in Ethiopia (Table 6). This agreement was in line with Mekuria Temtme et al (2018) who clarified that introduced breeding materials contributed a lot to the improvement of the grain yield potential of durum wheat and haricot bean varieties in Ethiopia. Genet Mengistu et al (2020) on chickpea also added that, selection from introductions and hybridization as major breeding methods and it was successful in improving the grain yield potential and other agronomic traits rather than selection from landraces.
3.3.2. Hundred Seed weight (HSW), Biomass yields (BMY) and Plant count at harvest (PCH)
In the Desi type chickpea varieties the mean hundred seed weight of varieties released in 1970s, 1980s, 1990s and 2000s were12.3, 21.8, 19.0 and 23.51g (Table 5), in that order. These result indicated an increase of 9.5g (77.2%), 6.7g (25.9%) and 11.21g (91.13%) over the first released variety (Table 5), respectively. The mean hundred seed weight of the varieties released in the 2000s was better than that of the first released variety (DZ 10 11) in 1974, the 1980s, and the 1990s (Table 5). This provides insights into possible future opportunities to exploit the genetic potential of crops for enhanced chickpea production. Interims of the Kabuli type chickpea varieties the mean hundred seed weight of varieties released in 1970s, 1990s and 2000s were 18.8, 26.9and 32.21g (Table 5), in that order. This result point out an increase of 8.1 g (43.1%) and 13.4 g (71.32%), respectively, over the first released variety (Table 5). In this context, in Ethiopia chickpea breeding program has made strategic shift in its objective from simply yield deriver to some other market driver traits like seed size. For example, the variety Acos Dubie was released in 2009. This idea was in parallel with Megersa Tadesse et al (2018), who reported that, even though seed yield is the primary character of interest and the prime objective in most of the Ethiopian crop breeding programs for the last several decades, hundred seed weight/seed size has received special attention at both the national and international levels because in response to the current move towards meeting the export market demands for large-sized seeds. Tamene Temesgen et al. (2015) also reported that there was an increase in seed size over the years of release in faba bean.
In addition to this, the biomass yield of the Desi type chickpea varieties released in 1970s, 1980s,1990s and 2000s were 3074.9, 1772.2, 3858.3 and 5204.13Kg/ha (Table 5/Fig. 4), in that order. These result indicated an increase of -1,302Kg/ha (-42.4%), 783.4Kgha (25.5%) and 2129.2Kg/ha (69.25%) over the first released variety (Table 5/Fig. 4), in that order. The mean biomass yield of the varieties released in 2000s was good enough than that of the first released variety (DZ-10-11) in 1974 and 1980s and, 1990s (Table 5) because plant count at harvest maturity strongly determine the biomass yield so that the mean of plant count at harvest maturity in the Desi type chickpea varieties released in 1970s, 1980s, 1990s and 2000s were 28.5, 27.5, 30.7 and 34.93 (Table 5), in that order. These results indicate increase of 1.0 (3.54%), 2.2 (7.7%) and 6.43 (22.57%) over the first released variety (Table 5). The mean plant count at harvest maturity released in 2000s was better than that of the first released variety in 1974 (DZ 10 11) and 1980s and, 1990s (Table 5). Interims of the Kabuli type chickpea varieties the mean biomass yield of varieties released in 1970s, 1990s and 2000s were 4333.3, 5906.7 and 5493.75Kg/ha (Table 5), in that order. These result indicated an increase of 1,573.4Kg/ha (36.3%) and 1,485.5Kg/ha (39.51%) over the first released variety (Table 5), individually. The mean biomass yield released in 1990s was good enough than that of the first released variety in 1974 (DZ 10 4) and the mean plant count at harvest maturity released in 1980s and 1990s (Table 5/Fig. 4). Because like the Desi type chickpea varieties plant count at harvest maturity strongly determine the biomass yield in this context, the mean of plant count at harvest maturity in the Kabuli type chickpea varieties released in 1970s,1990s and2000s were 27.3, 32.75 and 32.63 (Table 5), in that order. These result indicated an increase of 545 (19.4%), and5.33 (19.53%) over the first released variety (Table 5), in that order. The mean plant count at harvest maturity released in 1990s was much improved than that of the first released variety in 1974 (DZ 10 4) and the mean plant count at harvest maturity released in 1980s and 1990s (Table 5). Over all, the count at harvest strongly determines the amount of biomass yield that a certain variety within a certain crop achieves. This suggestion was in line with Amare Tsehaye et al (2020) who reported that, varieties that had maximum above ground, biomass provides the highest grain yield and vice versa, indicating that biomass was the major yield attributing trait.
Table 5
Genetic gain trend in grain yield and related traits for Desi and Kabuli type chickpea over the older variety released in 1974
Desi type | Year of release | Mean GY (Kg/ha) | Increment over DZ-10-11 | Mean HSW (gm) | Increment over DZ-10-11 | Mean BMY (Kg/ha) | Increment over DZ-10-11 | PCH | Increment over DZ-10-11 |
Kg | % | Kg | % | Kg | % | Mean No | % |
DZ-10-11 | 1970s | 1606.2 | ----- | ------ | 12.3 | ------ | ------ | 3074.9 | ------ | ----- | 28.5 | ------- | ------ |
Mariye | 1980s | 878.5 | -727.7 | -45.3 | 21.8 | 9.5 | 77.2 | 1772.2 | -1,302 | -42.4 | 27.5 | 1 | 3.54 |
Akaki | 1990s | 2023.6 | 417.4 | 25.9 | 19.0 | 6.7 | 54.5 | 3858.3 | 783.4 | 25.5 | 30.7 | 2.2 | 7.7 |
Kutaye | 2000s | 2469.62 | 863.42 | 53.7 | 23.51 | 11.21 | 91.13 | 5204.13 | 2129.2 | 69.25 | 34.93 | 6.43 | 22.57 |
Mastewal |
Fetenech |
Natoli |
Minjar |
Teketay |
Dalota |
Dimtu |
Geletu |
Eshete |
Kabuli type |
DZ-10-4 | 1970s | 2156.9 | ------ | ------ | 18.8 | ------ | ------ | 4333.3 | ------- | ------- | 27.3 | ------- | ------- |
Shasho | 1990s | 2583.7 | 426.8 | 19.8 | 26.9 | 8.1 | 43.1 | 5906.7 | 1,573.4 | 36.3 | 32.75 | 5.45 | 19.4 |
Arerti |
Habru | 2000s | 2485.71 | 328.81 | 15.25 | 32.21 | 13.41 | 71.32 | 5493.75 | 1,485.5 | 39.51 | 32.63 | 5.33 | 19.53 |
Chefe |
Teji |
Ejeri |
Yelbie |
Acos Dubie |
Kasech |
Akuri |
Kobo |
Hora |
Dhera |
Koka |
GY, grain yield; HSW, Hundred seed weight; BMY, Biomass yield; PCH, Plant count at harvest.
The genetic gain analysis showed an average rate of increase of 33.44kgha− 1 year− 1 in grain yield potential over the last 46 years since 1974 to 2020 (Fig. 2) in the Desi type chickpea varieties, in which it was a highly significant (P ≤ 0.01) effect. The average relative annual gain in grain yield was 2.08% per year or about 95.68% for the whole period (Tables 8 and 9).This evidently showed thatchickpea breeders have made tremendous efforts over the last 46 years to improve the yield of Desi type chickpea in Ethiopia. This suggestion was in line with Tibebu Belete et al (2017) who reported that, grain yield potential of Desi type chickpea has not attained yield plateau in Ethiopia; indicating that the huge opportunity for breeders to improve further through the existing breeding tactic. Follmann et al (2017) also found that the annual genetic progress of sunflower during the period of 10 years (2005–2014) was 132.46 kgha− 1year− 1 for grain yield.
Likewise, In the Kabuli type chickpea varieties the genetic gain analysis revealed an average rateof increase of 7.9kg/ha/year in yield potential over the last 45 years since 1974 to 2019 (Fig. 1),which was a non significant (P ≥ 0.05) effect. The average relative annual gain in grain yield was 0.37% per year or about 16.65% for the whole period (Tables 8 and 9). This obviously showed that chickpea breeders have made efforts over the last 45 years to improve the yield of Kabuli type chickpea varieties in Ethiopia but the improvement for yield achievement was not as such countless as compared to the Desi type chickpea (Tables 8 and 9). Similarly, Megersa Tadesse et al (2018) reported that the mean relative annual gain in grain yield of Kabuli type chickpea varieties since 1974 was a 0.57% increase per year or about 23.37% for the whole period of 41 years. Nigussie Kefelegn et al. (2020) also reported that yield gain was minimal in large-seeded common bean.
Table 6
Average increments in grain yield and hundred seed weight (HSW) for Desi and Kabuli type chickpea varieties derived from introduction over variety derived from local collection
| Grain yield (kg/ha) | Increment over local collection | Mean HSW (g) | Increment over local collection |
Desi types | | Kgha− 1 | % | | HSW (g) | % |
Local collection derived | 1606.2 | ------ | | 12.3 | ------ | |
Introduction derived | 2299.86 | 693.66 | 43.19 | 22.99 | 10.69 | 86.91 |
Kabuli types | | | | | | |
Local collection derived | 2156.9 | ------ | | 18.8 | ------ | |
Introduction derived | 2499.71 | 342.81 | 15.89 | 31.45 | 12.65 | 67.28 |
3.3.2. Hundred Seed Weight (HSW)
In the Desi, type chickpea varieties the mean hundred seed weight ranged from 12.3 g (DZ-10-11) to 30.0 g (Geletu and Dimtu) with across location average of 22.18 g (Table 7). The varieties Geletu and Dimtu, which were released in 2016 and 2019, respectively, had significantly higher hundred seed weights than all of the varieties in this trial. They surpassed the first older variety (DZ-10-11) by 17.7 g (143.9%). The mean hundred seed weight of varieties that released in 1974, 1985,1995, 2005, 2006 ,2006, 2007,2010,2013,2013, 2016,2019 and 2020 were 12.3, 21.8, 19.0, 19.3, 20.7, 19.8, 27.0, 19.5, 26.8, 25.5, 30.0, 30.0 and 16.5g, respectively (Table 7). This showed that an increase of 9.5g (77.24%), 6.7g (54.47%), 7g (56.91%), 8.4g (68.29%), 7.5g (60.98%), 14.7g (119.5%), 7.2 (58.54%), 14.5g (117.89%),13.2 (107.32%),17.7 (143.9%) over the older variety in that order. In the Kabuli, type chickpea varieties the mean hundred seed weight ranged from 18.8 g (DZ-10-4) to 48.0 g (Acos Dubie) with across location average of 30.6 g (Table 7). The varieties Acos ubie, which were released in 2009, had significantly higher seed size (hundred seed weight) than all of the varieties in this study. They surpassed the first older variety (DZ-10-11) by 29.2g (155.32%) in hundred seed weight. The mean hundred seed weight of varieties that released in 1974, 1999, 1999, 2004, 2004,2005,2005, 2006,2009,2011, 2011,2012,2016,2016 and2019 were 18.8, 27.8, 26.0, 25.7,32.2,29.8,28.2,30.2,48.0,29.8, 32.3, 31.7, 30.7, 33.2 and 34.7 respectively (Table 7). This showed that an increase of 9g (47.87%), 7.2g(38.29%), 6.9g(36.7%), 13.4g (71.27%), 11g (58.51%), 9.4g (50%), 11.4 (60.64%), 29.2g (155.32%),11(58.51%),13.5 (71.81%), 12.9 (68.62%),11.9 (63.29%),14.4(76.60%) and 15.9 (84.57%) in hundred seed weight over the older variety. Tamene Temesgen et al (2015) in faba bean and Ersullo Lirie et al (2016) found that the thousand-seed weight of modern varieties was higher than that of older varieties.
Table 7
Genetic gain trend in grain yield and related traits for Desi and Kabuli type chickpea over the older variety released in 1974
Desi type | Year of release | Mean GY (Kg/ha) | Increment over DZ-10-11 | Mean HSW (gm) | Increment over DZ-10-11 | Mean BMY (Kg/ha) | Increment over DZ-10-11 | PCH | Increment over DZ-10-11 |
Kg | % | Kg | % | Kg | % | Mean No | % |
DZ-10-11 | 1974 | 1606.2 | ----- | ------ | 12.3 | ------ | ------ | 3074.9 | ------ | ----- | 28.5 | ------- | ------ |
Mariye | 1985 | 878.5 | -727.7 | -45.3 | 21.8 | 9.5 | 77.2 | 1772.2 | -1,302 | -42.4 | 27.5 | 1 | 3.54 |
Akaki | 1995 | 2023. | 417.4 | 25.9 | 19.0 | 6.7 | 54.5 | 3858.3 | 783.4 | 25.5 | 30.7 | 2.2 | 7.7 |
Kutaye | 2005 | 2195.2 | 589 | 36.7 | 19.3 | 7 | 56.9 | 4574.9 | 1500 | 48.8 | 33.3 | 4.8 | 16.8 |
Mastewal | 2006 | 2,015.15 | 408.95 | 25.5 | 20.25 | 7.95 | 64.63 | 4426.1 | 1,351.2 | 43.94 | 31.4 | 2.9 | 10.18 |
Fetenech | 2006 |
Natoli | 2007 | 2782.5 | 1,176.3 | 73.2 | 27.0 | 14.7 | 119.5 | 5613.9 | 2,539 | 82.6 | 37.5 | 9 | 31.6 |
Minjar | 2010 | 2407.6 | 801.4 | 49.9 | 19.5 | 7.2 | 58.5 | 5041.7 | 1,966.8 | 63.9 | 34.2 | 5.7 | 20 |
Teketay | 2013 | 2863.55 | 1,257.4 | 78.3 | 26.15 | 13.9 | 113.0 | 5844.55 | 2,769.7 | 90.1 | 37.25 | 8.75 | 30.7 |
Dalota | 2013 |
Dimtu | 2016 | 2319.4 | 713.2 | 44.4 | 30.0 | 17.7 | 143.9 | 5316.7 | 2,241.8 | 72.9 | 34.7 | 6.2 | 21.8 |
Geletu | 2019 | 2627.8 | 1,021.6 | 63.6 | 30.0 | 17.7 | 143.9 | 5466.7 | 2,391.8 | 77.8 | 35.8 | 7.3 | 25.6 |
Eshete | 2020 | 2606.3 | 1,000.1 | 62.3 | 16.5 | 4.2 | 34.2 | 5486.1 | 2,411.2 | 78.4 | 36.5 | 8 | 28.1 |
Kabuli type |
DZ-10-4 | 1974 | 2156.9 | ------ | ------ | 18. | ------ | ------ | 4333.3 | ------- | ------- | 27.3 | ------- | ------- |
Shasho | 1999 | 2583.7 | 426.8 | 9.79 | 26.9 | 8.1 | 43.09 | 5906.7 | 1,573.4 | 36.30 | 32.75 | 5.45 | 19.96 |
Arerti | 1999 |
Habru | 2004 | 2866 | 709.1 | 32.9 | 28.95 | 10.2 | 53.99 | 5997.25 | 1,663.9 | 38.4 | 34.8 | 7.5 | 27.47 |
Chefe | 2004 |
Teji | 2005 | 2231.6 | 74.7 | 3.46 | 29 | 10.2 | 54.26 | 5192.6 | 859.3 | 19.83 | 33.3 | 6 | 21.98 |
Ejeri | 2005 |
Yelbie | 2006 | 1981.9 | -175 | -8.1 | 30.2 | 11.4 | 60.6 | 4636.1 | 302.8 | 69.9 | 28.5 | 1.2 | 4.4 |
Acos Dubie | 2009 | 2781.9 | 625 | 28.9 | 48.0 | 29.2 | 155.3 | 5875. | 1,541.7 | 35.6 | 29.5 | 2.2 | 8.1 |
Kasech | 2011 | 2424.65 | 267.75 | 12.41 | 31.05 | 12.25 | 65.16 | 5230.6 | 897.3 | 20.71 | 31.8 | 4.5 | 6.48 |
Akuri | 2011 |
Kobo | 2012 | 1994.5 | -162.4 | -7.5 | 31.7 | 12.9 | 68.6 | 4611.1 | 277.8 | 6.4 | 31. | 4.2 | 15.4 |
Hora | 2016 | 2530.55 | 373.65 | 17.32 | 31.95 | 13.15 | 69.95 | 5855.95 | 1,522.7 | 35.14 | 32.9 | 5.6 | 20.51 |
Dhera | 2016 |
Koka | 2019 | 2964.6 | 807.7 | 37.5 | 34.7 | 15.9 | 84.6 | 6250.0 | 1,916.7 | 44.2 | 36.5 | 9.2 | 33.7 |
The regression of hundred seed weight against the years of release showed an annual rate of genetic gain of 0.24 g yr− 1 (Fig. 3),reflecting a significant increase in the trait over the last 46 years of Desi-type chickpea improvement in Ethiopia, with a relative annual genetic gain of 1.92% (Tables 8 and 9). Like to the grain yield, varieties derived from introductions gave higher hundred seed weight, which was 22.99 g on average, and surpassed the mean of the varieties developed through local collection by 10.69 g (86.91%) (Table 6). Similarly, in the Kabuli-type chickpea varieties, the regression of hundred seed weight against the years of release showed an annual rate of genetic gain of 0.36 g yr− 1 (Fig. 3), reflecting a significant increase in the trait over the last 45 years of Kabuli-type chickpea improvement in Ethiopia, with a relative annual genetic gain of 1.94% (Tables 8 and 9). Generally, this experiment clearly revealed that improved genetic progress was obtained by breeding Kabuli-type chickpea varieties in Ethiopia for seed size compared to grain yield. As if to the grain yield, varieties derived from introductions gave higher hundred seed weight, which was 31.45 g on average, and topped the mean of the varieties developed through local collection by 12.65 g (67.28%) (Table 6). Similar results were reported by Genet Menigusitu et al., 2020; Dagnachew Bekele et al., 2020)
Table 8
Comparative genetic gain study between Desi and Kabuli type chickpea varieties from linear regression of the mean value of each character for each variety against the year of release
| Desi type | Kabuli type |
Parameters | Mean | R2 | b | Intercept | | Mean | R2 | b | Intercept |
STC | 66.03 | 0.4787 | 0.7843 | -1506.8 | | 66.13 | 0.007362 | 0.086571 | -107.5273 |
DF | 57.1 | 0.0108 | -0.0493 | 155.9 | | 58.56 | 0.002144 | 0.02652 | 5.34712 |
DPM | 109.2 | 0.00165 | -0.0542 | 218.04 | | 113.8 | 0.01844 | 0.245 | -377.656 |
NPB | 4.35 | 0.05545 | -0.0175 | 39.489 | | 3.92 | 0.001078 | 0.002287 | -0.666546 |
NSB | 37.5 | 0.0503 | -0.4718 | 983.64 | | 29.81 | 0.01292 | -0.2097 | 450.4080 |
NPP | 78.8 | 0.0971 | -0.8312 | 1745.56 | | 55.12 | 0.08384 | -0.4651 | 988.0725 |
NSP | 1.70 | 0.00332 | -0.00202 | 5.75249 | | 1.87 | 0.008812 | 0.009837 | -17.85987 |
PH | 43.1 | 0.07022 | 0.2328 | -423.686 | | 46.93 | 0.01248 | 0.1358 | -225.4562 |
PCH | 33.54 | 0.4313 | 0.2133 | -394.151 | | 32.3 | 0.09512 | 0.1187 | -205.8700 |
HSW | 22.18 | 0.2737 | 0.2362 | -451.544 | | 30.6 | 0.2141 | 0.3638 | -699.2354 |
BMY | 4672.8 | 0.5951 | 77.78 | -151300.0 | | 5471.4 | 0.06736 | 25.20799 | -45095.78 |
GY | 2246.5 | 0.4437 | 33.442 | -64815.9 | | 2476.9 | 0.0212 | 7.887 | -13343.92 |
HI | 0.48 | 0.06678 | -0.00133 | 3.143631 | | 0.45 | 0.001257 | 0.000178 | 0.095658 |
Table 9
Annual relative genetic gain and correlation coefficients for grain yield and related traits of Desi and Kabuli type chickpea
| Desi type | Kabuli type |
| | Correlation coefficient (r) | | | | Correlation coefficient (r) |
Parameters | DZ-10-4 | Gain (% year) | GY | HSW | BMY | PCH | | DZ-10-11 | Gain (% year) | GY | HSW | BMY | PCH |
STC | 49.2 | 1.59 | 0.47*** | 0.38*** | 0.64*** | 0.69*** | | 61.3 | 0.14 | 0.43*** | 0.0021 | 0.61*** | 0.62*** |
DF | 59.0 | -0.084 | -0.32** | -0.09 | -0.12 | 0.21 | | 56.5 | 0.05 | 0.00 | 0.24* | 0.31** | 0.15 |
DPM | 106.5 | -0.051 | -0.46*** | 0.03 | -0.23* | 0.16 | | 108.0 | 0.22 | -0.15 | 0.35*** | 0.19 | 0.16 |
NPB | 4.1 | -0.43 | -0.25* | -0.20 | -0.28 | -0.15 | | 3.6 | 0.06 | 0.16 | -0.32** | 0.22* | 0.06 |
NSB | 50.3 | -0.93 | 0.06 | -0.24* | -0.17 | -0.34** | | 40.1 | -0.53 | 0.03 | -0.39*** | -0.29** | -0.28** |
NPP | 102.9 | -0.80 | -0.31** | -0.23* | -0.32** | -0.12 | | 76.1 | -0.61 | -0.03 | -0.32** | -0.07 | -0.12 |
NSP | 1.6 | -0.13 | 0.16ns | -0.18 | -0.02 | -0.10 | | 1.8 | 0.55 | 0.11 | -0.14 | 0.05 | -0.15 |
PH | 37.4 | 0.62 | -0.10 | 0.08 | 0.12 | 0.36** | | 43.1 | 0.32 | 0.14 | 0.29** | 0.44*** | 0.25* |
PCH | 28.5 | 0.75 | 0.62*** | 0.42*** | 0.69*** | --------- | | 27.3 | 0.44 | 0.45*** | 0.17 | 0.52*** | -------- |
HSW | 12.3 | 1.92 | 0.32** | --------- | 0.42*** | 0.42*** | | 18.8 | 1.94 | 0.17 | -------- | 0.22* | 0.17 |
BMY | 3074.9 | 2.53 | 0.89*** | 0.42*** | -------- | 0.69*** | | 4333.3 | 0.58 | 0.52 | 0.22* | -------- | 0.52*** |
GY | 1606.2 | 2.08 | --------- | 0.32** | 0.89*** | 0.62*** | | 2156.9 | 0.37 | --------- | 0.08 | 0.75*** | 0.45*** |
HI | 0.53 | -0.25 | 0.19 | -0.26* | -0.24* | -0.19 | | 0.44 | 0.04 | 0.14 | -0.06 | 0.02 | 0.14 |
3.3.3. Plant height
Among the newly released Desi type chickpea varieties, the tallest mean plant height was observed in the variety ‘Eshete’ (56.8 cm) which was released in 2020 while ‘DZ-10-11’(37.4 cm),which was released in 1974 had the shortest plant height (Table 4). The regression of plant height against the years of release showed an annual rate of genetic gain of 0.23 cm ha− 1 year− 1 (Table 8) with a relative annual genetic gain of 0.62% (Table 9). Within the same fashion, in the Kabuli type chickpea varieties, the tallest plant height was observed in the variety ‘Dhera’ (54.6 cm) which was released in 2019 whereas ‘DZ-10-4’, which was released in 1974 (43.1 cm) had the shortest plant height (Table 4). The regression of plant height against the years of release showed annual rate of genetic gain of 0.14 cm ha− 1year− 1 (Table 8) with a relative annual genetic gain of 0.32% (Table 9). Genet Mengistu et al (2020) support this result. However, Mihret Yirgu et al (2015) reported a negatively non-significant annual rate of gain in plant height against year of release with the average annual genetic gain and annual relative percentage gain of -0.39 cm year− 1 and − 0.16% per year.
3.3.4. Number of Pods per plant and seeds per pod
In the Desi type chickpea varieties, the mean number of pods per plant (NPP) and number of seeds per pod (NSP) averaged across location were 78.8 and 1.70 respectively (Table 4). From this trail, the number of pods per plant (NPP) and number of seeds per pod (NSP) followed a decreasing trend over 46 years of Desi type chickpea improvement program with relative annual gains of -0.80 and − 0.13, in that order (Table 8). The slightly negative progress in the number of pods plant− 1 was due to a negative response to a slight increase in seed size during the period of variety development (Tibebu Belete et al., 2017). In the Kabuli type chickpea varieties, the mean number of pods per plant (NPP) and number of seeds per pod (NSP) across location were 55.12 and 1.87, respectively (Table 4). With a relative annual gains of -0.61 and 0.55, respectively, during the course of the improvement program over the past 45 years respectively (Table 8). This idea is in agreement with Genet Mengistu et al (2020), who reported that the number of pods per plant and number of seeds per pod followed a decreasing trend over 42 years of the Kabuli-type chickpea improvement program in Ethiopia.
3.3.5. Days to flowering and maturity
In the Desi type chickpea varieties the recently released variety, Eshete (63.0,122.2 days) were the latest to reach flowering and physiological maturity (Table 4), while Natoli and Geletu (released in 2007 and 2019) were the earliest (103.3 and 105.5 days) to mature (Table 4). The regression analysis of days to flowering against the year of release indicated a non- significant negative decrease in annual genetic gain (-0.05days per year (Table 8) with a relative genetic gain of -0.084% (Table 9). In addition, days to physiological maturity showed a non- significant negative decrease in annual genetic gain of -0.0542 days per year (Table 8), with a relative genetic gain of -0.051% (Table 9). This might reveal that there was a significant improvement in days to flowering and maturity from the old to recent varieties. Fikre Hagos et al (2012) reported a negative genetic gain for the number of days to 50% flowering in common beans. However, Genet Mengistu et al. (2020) reported that regression analysis of days to flowering against the year of release indicated a non- significant increase in annual genetic gain of 0.0045 days per year. In the Kabuli, type chickpea varieties the varieties such as Arerti (63.0days) and Dhera (129.0days) were the latest to reach 50% flowering and physiological maturity (Table 4), while Chefe (54.8 days) and Kasech (104.7days) followed by Koka (106.0days) were the earliest to flower and mature (Table 4). Megersa Tadesse et al (2018) reported days to flowering ranged from 43 to 60.75 with a mean value of 51.9 days in the Kabuli type chickpea varieties. Regression analysis of days of flowering against the year of release indicated a non-significant positive increase in annual genetic gain of 0.027days per year (Table 8) with a relative genetic gain of 0.05% (Table 9). In addition, days to physiological maturity showed a non-significant positive increase in annual genetic gain of 0.25days per year (Table 8), with a relative genetic gain of 0.22% (Table 9). This indicates that the breeding program had failed to reduce the days to flowering and maturity of Kabuli type chickpea varieties. Similarly, Mekuria Temtme et al. (2018) who reported that, a non significant increase in days to physiological maturity in haricot bean, faba bean, and soybean and durum wheat breeding, in that orders. In contrast, Daniel Admasu et al. (2015) reported that the relative annual genetic gain from 1980 to 2010 was 19.5% (Debre Zeit) and 6% (Enewari) for days to flowering and 7.5% (Debre Zeit) and 3.9% (Enewari) for physiological maturity in lentils.
3.4. Correlation between traits
The correlation coefficients of grain yield for all the traits studied are presented in Table 10/Fig. 5. In the Desi-type chickpea varieties, a highly significant and positive correlation was observed between plant count at harvest and biomass (r = 0.69) and grain yield (r = 0.62). Because the seedling stand count was strongly and positively correlated with plant count (r = 0.69) and plant height (r = 0.41), as with the highest plant population, there might be resource competition such as sunlight. Improvement in the grain yield potential of Desi-type chickpea varieties was associated with a parallel increase in biomass yield (Tibebu Belete et al., 2017). However, there was a non-significant negative association between grain yield and plant height (r=-0.10). It is often common to see high chickpea plants with pod-bearing parts raised above the shade zone, which indicates a small area for pod production. Mihret Yirgu et al (2015) also reported statistically non significant associations between grain yield and plant height in teff, malt barley, and lowland sorghum. Therefore, a non-significant and negative correlation was observed between grain yield and the number of pods plant− 1(r=-0.31), while the number of seeds pod− 1(r = 0.16) and hundred-seed weight (r = 0.32) were positively and significant associated with grain yield (Table 10). Hundred seed weight showed a significant negative association with the number of pods plant− 1 and non-significant negative associations with the number of seeds pod− 1 (r=-0.18). Genet Mengistu et al (2020) also reported similar results. Finally, there was a significant negative correlation between days of 50% flowering (r=-0.32) and 90% physiological maturity (r=-0.46) with grain yield (Table 10/Fig. 5). This might be due to the nature of the variety meaning mostly varieties that have the longest maturity, and the flowering period might provide a higher yield than varieties that have the shortest maturity period.
Correspondingly, in the Kabuli type chickpea varieties the result showed that a highly significant and positive correlation was observed between plant count at harvest with biomass (r = 0.52) and grain yield (r = 0.45). Because seedling stand count strongly and positively correlated with plant count at harvest (r = 0.62) with plant height (r = 0.35). However, there was non-significant positive association between grain yield and plant height (r = 0.14). Therefore, a non-significant and negative correlation was observed between grain yield and the number of pods plant− 1(r=-0.03), and the number of seeds pod− 1(r = 0.11) and hundred-seed weight (r = 0.08) showed a positive and non- significant association with grain yield (Table 10/Fig. 5). Kulwal and Mhase (2016) reported that grain yield is mostly influenced by seed weight, which enhances the assimilation of metabolites and their transformation into yield components. Hundred seed weight was significantly and negatively associated with the number of pods plant− 1(r=-0.32) and non-significant and negatively associated with the number of seeds pod− 1 (r=-0.14). This is because more seeds per pod might cause a reduction in the average seed size due to competition among seeds for limited food reserves (Genet Mengistu et al., 2020). Finally, there was a negative and significant correlation between days of 90% physiological maturity (r=-0.15) and grain yield (Table 10/Fig. 5). This might be due to the nature of the variety, meaning that varieties with the longest physiological maturity period might have a higher yield than varieties with the shortest maturity period. This result is in agreement with Megersa Tadesse et al. (2018), who found that in the Kabuli-type chickpea varieties, yield loss occurred for early maturing varieties and yield gain for late-maturing varieties. Late flowering and maturing varieties may successfully exploit the available moisture and perform better than early varieties that cannot fully exploit moisture (Gemechu Keneni et al., 2014).
Table 10
Assessing correlation coefficient among traits of Desi and Kabuli type chickpea varieties
Desi type | STC | DF | DPM | NPB | NSB | NPP | NSP | PH | PCH | GY | HSW | BMY | HI |
STC | 1.000 | 0.04ns | 0.17ns | -0.25* | -0.49*** | -0.30** | -0.25* | 0.41*** | 0.69*** | 0.47*** | 0.38*** | 0.64*** | -0.39*** |
DF | | 1.0000 | 0.76*** | 0.07ns | -0.46*** | 0.25* | -0.20ns | 0.62*** | 0.21ns | -0.32** | -0.09ns | -0.12ns | -0.37*** |
DPM | | | 1.0000 | 0.13ns | -0.58*** | 0.25* | -0.29* | 0.78*** | 0.16ns | -0.46*** | 0.03ns | -0.23* | -0.50*** |
NPB | | | | 1.0000 | 0.15ns | 0.04ns | 0.04ns | 0.06ns | -0.15ns | -0.25* | -0.20ns | -0.28ns | 0.02ns |
NSB | | | | | 1.0000 | 0.42*** | 0.23* | -0.70*** | -0.34** | 0.06ns | -0.24* | -0.17ns | 0.50*** |
NPP | | | | | | 1.00000 | 0.00ns | -0.05ns | -0.12ns | -0.31** | -0.23* | -0.32** | 0.04ns |
NSP | | | | | | | 1.00000 | -0.21ns | -0.10ns | 0.16ns | -0.18ns | -0.02ns | 0.35** |
PH | | | | | | | | 1.0000 | 0.36** | -0.10ns | 0.08ns | 0.12ns | -0.46*** |
PCH | | | | | | | | | 1.000 | 0.62*** | 0.42*** | 0.69*** | -0.19ns |
GY | | | | | | | | | | 1.0000 | 0.32** | 0.89*** | 0.19ns |
HSW | | | | | | | | | | | 1.0000 | 0.42*** | -0.26* |
BMY | | | | | | | | | | | | 1.0000 | -0.24* |
HI | | | | | | | | | | | | | 1.0000 |
Kabuli type |
STC | 1.000 | 0.32** | 0.27* | 0.24* | -0.29* | 0.10ns | -0.12ns | 0.35*** | 0.62*** | 0.43*** | 0.00208 | 0.61*** | -0.1152 |
DF | | 1.0000 | 0.73*** | 0.09ns | -0.63*** | 0.04ns | -0.42*** | 0.60*** | 0.15ns | 0.00ns | 0.24* | 0.31** | -0.37*** |
DPM | | | 1.0000 | 0.03ns | -0.67*** | 0.11ns | -0.50*** | 0.68*** | 0.16ns | -0.15ns | 0.35*** | 0.19ns | -0.52*** |
NPB | | | | 1.0000 | 0.14ns | 0.15ns | 0.09ns | -0.09ns | 0.06ns | 0.16ns | -0.32** | 0.22* | -0.08ns |
NSB | | | | | 1.0000 | 0.36*** | 0.52*** | -0.69*** | -0.28** | 0.03ns | -0.39*** | -0.29** | 0.39*** |
NPP | | | | | | 1.0000 | -0.07ns | 0.10ns | -0.12ns | -0.03ns | -0.32** | -0.07ns | -0.09ns |
NSP | | | | | | | 1.0000 | -0.47*** | -0.15ns | 0.11ns | -0.14ns | 0.05ns | 0.27** |
PH | | | | | | | | 1.0000 | 0.25* | 0.14ns | 0.29** | 0.44*** | -0.34** |
PCH | | | | | | | | | 1.0000 | 0.45*** | 0.17ns | 0.52*** | 0.14ns |
GY | | | | | | | | | | 1.00000 | 0.08ns | 0.75*** | 0.48*** |
HSW | | | | | | | | | | | 1.00000 | 0.22* | -0.06ns |
BMY | | | | | | | | | | | | 1.0000 | 0.02ns |
HI | | | | | | | | | | | | | 1.0000 |
Stepwise regression analyses using grain yield as a dependent variable indicated that, hundred seed weight (HSW) and number of seeds per pod (NSP) were very important traits that can contribute to grain yield. In particular, 10.56% by hundred seed weight and 2.54% was contributed by the number of seeds per pod to grain yield (Table 11). This illustrates that an improvement in grain yield was achieved by a combination of different factors. Stepwise regression analyses showed using hundred seed weight as the dependent variable, which contributed to an economic trait in the Desi-type chickpea, the number of pods per plant (NPP) had a declining effect, contributing to the variation among the varieties in hundred seed weight. The number of pods per plant also explained approximately 5.17% of the variation in the seed size of Desi-type chickpea varieties. Similarly, in the Kabuli type chickpea varieties, grain yield as the dependent variable indicated that, hundred seed weight and number of seeds per pod (NSP) contributed to grain yield. For the most part, 71% by hundred seed weight and 112% was contributed by the number of seeds per pod (Table 11). Furthermore, stepwise regression analyses showed using hundred seed weight as the dependent variable, which is an economic trait in Kabuli type chickpea, and the number of pods per plant explained about 201% of the variation in the Kabuli type chickpea varieties in seed size (Table 11). Genet Mengistu et al (2020) reported that, in the Kabuli-type chickpea varieties, the number of pods per plant (NPP) had a declining effect, contributing to the variation among the varieties in hundred-seed weight.
Table 11
Summary result of selection from stepwise regression analysis of mean grain yield and hundred seed weight as dependent variable and the other traits as independent variable
Desi types | Grain Yield | |
Independent Variable | Regression coefficient (b) | R2 (%) |
Hundred seed weight (HSW) | 36.13** | 10.56 |
Number of seed per pod (NSP) | 228.0ns | 2.54 |
| Hundred seed weight | |
Number of pods per plant | -0.03849* | 5.17 |
Kabuli types | Grain Yield | |
Independent Variable | Regression coefficient (b) | R2 (%) |
Hundred seed weight (HSW) | 5.802ns | 0.71 |
Number of seed per pod (NSP) | 54.63ns | 1.12 |
| Hundred seed weight | |
Number of pods per plant (NPP) | -1.064ns | 2.01 |