Multivariate analysis for morpho-physiological and milling traits along with molecular profiling of known bacterial blight resistance genes in advanced breeding lines of rice

Rice (Oryza sativa L.) yield, quality and resistance to various biotic and abiotic stresses are the major barriers of rice production worldwide. Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae, is a major cause of reduced yield in rice. In the present study, a set of 43 advance breeding lines along with 6 check varieties was evaluated for yield attributes, milling quality traits and BB resistance. The results indicated a significant variation for various morpho-physiological and milling traits. Disease screening was carried out in field at maximum tillering stage under artificial inoculation conditions. Based on pathogenicity test, 36 genotypes showed resistance to all the ten BB pathotypes prevalent in northern India (Punjab). Further, these lines were characterized for known BB resistance gene(s); Xa4, xa5, xa13 and Xa21 using linked molecular markers and molecular analysis showed a wide range of gene combinations and indicated the presence of single (6), two (23), and three (13) gene combinations while one line (PAU 5285-23-1-2) showed none of the known gene tested. The genotypes PAU 7261-19-1, PAU 6998-110-3-1, PAU 6516-11-1-2-1-1, PAU 6554-1-1-1-2-3, PAU 6970-18-1-3, PAU 6707-33-6-1-1-1-3 had significantly and consistently high yield with early maturity, semi dwarf, good tillering along with desirable quality traits. Moreover, these are resistant to all ten pathotypes of BB presently prevalent in the Punjab state. Therefore, it is recommended that these can be utilized further to identify and develop improved varieties with high yield, early to mid-maturity, desirable milling quality and BB resistance.