Evaluation of recombinant inbred lines of IR20 and Nootripathu for root traits

Abstract

Root length and rapid elongation of roots during early stages of growth determines drought tolerance in rice. Some of the traditional rice genotypes including Nootripathu, a drought tolerant upland rice genotype possesses the above drought adaptive traits but no attempts have been made to map them. In this study, a set of 100 advanced generation Recombinant Inbred Lines (RILs) developed between IR20 (shallow rooted) and Nootripathu (deep rooted) were carefully examined for their root growth behaviour. Parents, IR20 and Nootripathu exhibited significant differences in their radicle emergence, root elongation rate and root length on 3rd and 9th day after germination. RILs exhibited continuous genetic variation for root length and crown root number and revealed its suitability for genetic mapping of various root growth traits.