Molecular Screening and Agronomic Trait Characterization of NLR 34449 X ISM Derived Population for their resistance against Bacterial Blight Disease

Abstract

Bacterial Blight (BB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major limiting factor amongst the diseases of rice in India. NLR34449 is a very popular high yielding variety. It is a popular variety not only in Andhra Pradesh but also in the neighbouring states of South India, but highly susceptible to the bacterial blight disease. A total of 802 BC1 F2 plants derived from the cross NLR 34449 and ISM were phenotypically screened for bacterial blight resistance, 687 were found to be resistant to BB. Genotyping of these plants revealed ten homozygous positive plants for all the three target BB genes viz., Xa21, xa13 and xa5. They were further assessed for key agro-morphological traits. viz., Days to 50% flowering, plant height, number of panicles per plant, thousand grain weight and grain yield per plant. Almost all the traits exhibited variation for key agronomic traits and among them, five plants were found to be performing well not only for bacterial blight resistance but also found to be superior in terms of key agronomic traits like thousand grain weight and single plant yield and flowered earlier than the parents as well. These identified plants will be advanced for further evaluation.