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20151
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Subject: Molecular Biology and Biotechnology × Author: Baliyan, Nikita × Start date: 1999 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Molecular breeding for pyramiding bacterial leaf blight resistance genes in rice (Oryza sativa L.)
    (CCSHAU, 2015) Baliyan, Nikita; Boora, K.S.
    Rice (Oryza sativa) is an important cereal food crop that serve as a major carbohydrate source for half of the world’s population. Bacterial leaf blight (BLB), caused by the bacterium, Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threat to the rice production. The present work was undertaken to introgress the major BLB resistance genes (Xa21, xa13 and xa5) into BLB susceptible rice variety CSR-30, from BLB resistant donor varieties Pusa Basmati -1460 (having two BLB resistance genes Xa21 and xa13) and IRBB-60 (having three BLB resistance genes Xa21, xa13 and xa5) through marker assisted selection. Foreground selection was carried out in the F2 plants of cross CSR-30 x Pusa Basmati-1460 and BC2F1 plants of cross CSR-30 x IRBB-60 using specific STS markers pTA248, RG136 and RG556 linked to Xa21, xa13 and xa5 genes, respectively. In cross CSR-30 x Pusa Basmati-1460, a total of six F2 plants were found to have both Xa21 and xa13 genes and in cross CSR- 30 x IRBB-60, three BC2F1 plants were found to have all the three resistance genes Xa21, xa13 and xa5.These positive F2 (CSR-30 x Pusa Basmati-1460) and BC2F1 (CSR-30 x IRBB-60) plants were backcrossed with recurrent parent CSR-30. BC1F1 and BC3F1 seeds of these crosses were harvested separately. Foreground selection of BC1F1 and BC3F1 was carried out to confirm the presence of two and three BLB resistant genes using specific markers. Plants having two (CSR-30 x Pusa Basmati-1460) and three genes (CSR-30 x IRBB- 60) were selected for background selection. Four hundred and twenty eight SSR markers representing whole of the genome were used to identify polymorphism between parental genotypes out of which 111 and 131 SSR markers produced polymorphic alleles between parents CSR-30 and Pusa Basmati-1460 and parents, CSR-30 and IRBB-60, respectively. Finally, the maximum genome recovery for pyramided genotypes was analyzed by NTSYS and GGT softwares. The percentage recovery of recurrent parent genome in two-gene pyramided BC1F1 genotypes ranged from 62.7% to 83% and in three-gene pyramided BC3F1 genotypes, RPG ranged from 72.9% to 97.1%. Based on agronomic evaluation, BLB reaction, percentage recovery of recurrent parent genome, grain quality evaluation and aroma, four genotypes, C-70, C-123, C-142 and C-149 from cross CSR-30 x Pusa Basmati-1460 and four genotypes, R-28, R-68, R-32 and R-42 from cross CSR-30 x IRBB-60 were found promising. The four genotypes of cross CSR-30 x Pusa Basmati-1460 were backcrossed with CSR-30 and BC2F1 seeds were harvested. In cross CSR-30 x IRBB-60, the genotypes R-28, R-68, R-32 and R-42 were selfed and BC3F2 seeds were obtained. The present work demonstrates the successful pyramiding of bacterial leaf blight resistant genes Xa21, xa13 and xa5 into CSR-30 Basmati rice variety.