Establishment of indica TGMS lines with Pi-ja blast resistance gene
In the spring of 2011, the Pi-ja gene donor material 7001S was crossed with five indica TGMS lines including Guangmo S etc. in Lingshui, Hainan province. In the summer of 2011, F1 was planted in Hefei and backcrossed with the five parents including Guangmo S etc. to harvest BC1F1 seeds. In the spring of 2012, BC1F1 was planted in Hainan, and the excellent individual plants were selected by visual observation at heading date and then sampled for molecular assistant selection, and then the selected positive plants were backcrossed with the parental receptor to harvest BC2F1 seeds. In the summer of 2012, and 2013, 2014, 2015, the characters were selected systematically in favor of the recipient parent sterile line, and then molecular marker-assisted selection was carried out repeatedly, finally, indica TGMS lines weres obtained which was homozygous for Pi-ja and had stable comprehensive characters. And then through the identification of resistance to rice blast screening methods, five indica TGMS lines resistant to rice blast including Guangmo SJ, Xiner SJ, WA918SJ, W226SJ and W869SJ (The superscript of J indicated that the material contained Pi-ja gene), which were similar to their parents, were developed with Pi-ja gene (Fig. 1) .
Resistance of indica TGMS lines without and with Pi-ja gene
The seedlings blast resistance of TGMS lines without and with Pi-ja Gene was shown in Table 2. Without Pi-ja gene, there were three 2-grades, two 4-grades, and three R and two MS resistance types. With Pi-ja Gene, the resistance to blast was four 1 grade, one 3 grade, and the resistance types were four R and one MR. The seedlings blast resistance of W226S increased from 4 to 1, that of Guangmo S, Xiner S and W869S from 2 to 1, and that of WA918S from 4 to 3. The results showed that the Pi-ja resistant gene had a significant effect on rice seedlings blast.
Table 2
Blast resistance of indica TGMS lines without and with Pi-ja gene
No. | Materials | Sources | Seedlings blast | Panicle blast |
Resistance | Types | Resistance Change value | Resistance | Types | Resistance change value |
1 | Guangmo SJ | Guangmo S3/7001S | 1 | R | 1 | 3 | MR | 4 |
2 | Guangmo S | Guangzhan 63S-4/Molixinzhan | 2 | R | 7 | S |
3 | Xiner SJ | Xiner S3/7001S | 1 | R | 1 | 3 | MR | 2 |
4 | Xiner S | Xinan S2 /2301S | 2 | R | 5 | MS |
5 | WA918SJ | WA918S3/7001S | 3 | MR | 1 | 7 | S | 0 |
6 | WA918S | 1892S/Guangmo S | 4 | MS | 7 | S |
7 | W226SJ | W226S3/7001S | 1 | R | 3 | 3 | MR | 4 |
8 | W226S | P88S×Guangmo S | 4 | MS | 7 | S |
9 | W869SJ | W869S3/7001S | 1 | R | 1 | 3 | MR | 4 |
10 | W869S | Y58S×Aizi S | 2 | R | 7 | S |
Note: Resistance Change Value = Resistance grade of materials without Pi-ja gene - Rresistance grade of materials with Pi-ja gene. |
In addition, the resistance to panicle blast of indica TGMS lines without and with Pi-ja resistance gene can be seen from Table 2. Without Pi-ja gene, there were four 7-grade and one 5-grade resistance, four S and one MS resistance types. With Pi-ja Gene, the resistance to blast was four 3 grade, one 7 grade, and the resistance types were four MR and one S. The panicle blast resistance of Guangmo S, W226s and W869s increased from grade 7 to Grade 3, Xiner S from grade 5 to Grade 3, and WA918S remained grade 7. The results showed that the Pi-ja resistant gene also had a significant effect on rice panicle blast.
Comparative studies on disease resistance and yield of combinations of TGMS lines without and with Pi-ja gene
The results of the plot yield test of 12 combinations of indica TGMS lines Guangmo S, Xiner s, WA918S, W226S without and with Pi-ja resistance gene and restorer lines R2877, R900 and PR6547 are shown in Table 3.
Table 3
disease resistance and plot yield of indica TGMS lines without and with Pi-ja gene
Combinations | Seedlings blast | Panicle blast | the plot yield(kg/Mu, %) | Yield analysis | Rice qualities |
R | Types | R Change value | R | Types | R change value | Yield change | Percentage change(%) |
Guangmo SJ/R2877 | 1 | R | 2 | 3 | MR | 2 | 756.0/4.8 | 24.5 | 3.4 | Level 3 |
Guangmo S/R2877 | 3 | MR | 5 | MS | 731.5/1.4 | Level 3 |
Guangmo SJ/ R900 | 1 | R | 2 | 3 | MR | 4 | 766.8/6.3 | 28.1 | 3.9 | Level 3 |
Guangmo S/ R900 | 3 | MR | 7 | S | 738.7/2.4 | Level 3 |
Guangmo SJ/PR6547 | 1 | R | 0 | 3 | MR | 2 | 794.4/10.1 | 61.2 | 8.4 | Level 3 |
Guangmo S/PR6547 | 1 | R | 5 | MS | 733.2/1.7 | Level 3 |
WA918SJ/R2877 | 1 | R | 0 | 3 | MR | 0 | 725.3/0.6 | -55.7 | -7.7 | Level 3 |
WA918S/R2877 | 1 | R | 3 | MR | 781.0/8.3 | Level 3 |
WA918JS/ R900 | 2 | R | -1 | 3 | MR | 0 | 740.9/2.7 | 32.7 | 4.5 | Level 3 |
WA918S/ R900 | 1 | R | 3 | MR | 708.2/-1.8 | Level 3 |
WA918SJ/PR6547 | 1 | R | 0 | 3 | MR | 0 | 724.1/0.4 | -105.6 | -14.6 | Level 3 |
WA918S/PR6547 | 1 | R | 3 | MR | 829.7/15.0 | Level 3 |
Xiner SJ/R2877 | 1 | R | 3 | 3 | MR | 4 | 768.0/6.5 | 30.7 | 4.3 | Level 3 |
Xiner S/R2877 | 4 | MS | 7 | S | 737.3/2.2 | Level 3 |
Xiner SJ/ R900 | 1 | R | 2 | 3 | MR | 4 | 796.8/10.5 | 24.9 | 3.5 | Level 3 |
Xiner S/ R900 | 3 | MR | 7 | S | 771.9/7.0 | Level 3 |
Xiner SJ/PR6547 | 1 | R | 1 | 3 | MR | 2 | 788.4/9.3 | 41.8 | 5.8 | Level 2 |
Xiner S/PR6547 | 2 | R | 5 | MS | 746.6/3.5 | Level 2 |
W226SJ/R2877 | 1 | R | 0 | 3 | MR | 2 | 891.1/23.6 | 133.2 | 18.5 | Level 3 |
W226S/R2877 | 1 | R | 5 | MS | 757.9/5.1 | Level 3 |
W226SJ/ R900 | 1 | R | 2 | 3 | MR | 2 | 861.1/19.4 | 63.3 | 8.8 | Level 3 |
W226S/ R900 | 3 | MR | 5 | MS | 797.8/10.6 | Level 3 |
W226SJ/PR6547 | 1 | R | 1 | 3 | MR | 2 | 742.8/3.0 | -10.2 | -1.4 | Level 2 |
W226S/PR6547 | 2 | R | 5 | MS | 753.0/4.4 | Level 2 |
Note: R Change Value = Resistance without Pi-ja gene - Resistance with Pi-ja gene; Yield change = Yield of combination with Pi-ja gene - yield of combination without Pi-ja gene; Percentage change (%) = Percentage increase in yield (%) of combinations with Pi-ja gene - percentage increase in yield (%) of combinations without Pi-ja gene. |
The performance of seedling blast can be seen from Table 3. Without Pi-ja gene, there were five 1-grade, two 2-grades, four 3-grades, one 4-grade resistance, and seven R, four MR and one MS resistance types. With Pi-ja gene, there were eleven 1-grades, one 2-grade, and twelve R resistance types. Among them, two combinations of Guangmo S increased from Grade 3 to Grade 1, and one combination of WA918S decreased from grade 1 to Grade 2, the three combinations of Xiner S were increased from grade 4, Grade 3 and Grade 2 to Grade 1 respectively, and the two combinations of the W226s were increased from Grade 3 and Grade 2 to Grade 1 respectively. The resistance of other combinations did not change. Therefore, the Pi-ja Gene has an effect on the blast resistance of other combinations except WA918S.
In addition, the resistance to panicle blast can be seen from Table 3. Without Pi-ja gene, there were three 3-grades, six 5-grades, three 7grades, and three MR, six MS and three S resistance types. With Pi-ja gene, there were twelve 3-grades, and twelve MR resistance types. Among them, two combinations of Guangmo S increased from grade 5 to Grade 3, one combination increased from grade 7 to Grade 3, and three combinations of WA918S remained unchanged, the two combinations of Xiner S increased from 7 to 3, one from 5 to 3, and the three combinations of the W226s all increased from 5 to 3. Therefore, Pi-ja Gene had a significant effect on the resistance to panicle blast in all combinations except WA918S.
The yield of combinations without Pi-ja resistance gene and with Pi-ja resistance gene was compared from plot 12 of Table 3. The yield increasing range (kg) of the three combinations of Guangmo S were 24.5, 28.1 and 61.2, and the yield changing percentage (%) were 3.4, 3.9 and 8.4, respectively. The yield increases (kg) of three combinations of WA918S were − 55.7, 32.7, -105.6, and the yield change percentages (%) were − 7.7, 4.5, and 14.6, respectively. The yield increasing range (kg) of the three combinations of Xiner S were 30.7, 24.9 and 41.8, and the yield changing percentage (%) were 4.3, 3.5 and 5.8, respectively. The yield increasing range (kg) of three combinations of W226s was 133.2, 63.3, -10.2, and the yield changing percentage (%) was 18.5, 8.8, and-1.4, respectively. Therefore, except two combinations of WA918S and one combination of W226S, the other combinations all increased yield under the influence of Pi-ja resistance gene.
The Pearson Correlation analysis between the resistance of 12 combinations without and with Pi-ja resistance gene to seedling blast and panicle blast and the yield increase of the plot was carried out in Table 4, the correlation between the change of resistance to panicle blast and the increase of yield in the plot (r = 0.436, P = 0.157) was significantly higher than that between the change of resistance to seedling blast and the increase of yield in the plot (r = 0.130, P = 0.687).
Table 4
| Change of resistance to seedling blast | Change of resistance to panicle blast | Yield increases | Yield percentage change(%) |
Change of resistance to seedling blast | Pearson Correlation | | | | |
Sig. (2-tailed) | | | | |
N | | | | |
Change of resistance to panicle blast | Pearson Correlation | .816(**) | | | |
Sig. (2-tailed) | .001 | | | |
N | 12 | | | |
Yield increases | Pearson Correlation | .130 | .436 | | |
Sig. (2-tailed) | .687 | .157 | | |
N | 12 | 12 | | |
Yield percentage change(%) | Pearson Correlation | .132 | .437 | 1.000(**) | |
Sig. (2-tailed) | .682 | .155 | .000 | |
N | 12 | 12 | 12 | |
** Correlation is significant at the 0.01 level (2-tailed). |