Development of a method for testing dehydration tolerance rice(oryza sativa L.) and its application to a recombinant inbred line population

Abstract

A recombinant inbred line population derived from Japonica rice cultivar Hyogokithanishiki and Indica rice cultivar Hokuriku-142 is a valuable source for genetic and molecular studies as these two parents have different origins. Characterization of the two parents under different biotic and abiotic stress conditions exploits novel research areas such as QTL analysis. In the present study two parents were evaluated for dehydration tolerance using Petri dish method and nursery box method. Average root length, shoot length, root dry matter and shoot dry matter weight were evaluated in each method. Shoot length in nursery box method gave a significant difference between two cultivars with Hygokithanishiki dehydration tolerant and Hokuriku-142 dehydration susceptible. The method was applied to evaluate 163 recombinant inbred lines (RILs) derived from the two parents for dehydration tolerance. The trait showed a normal distribution in the population with some transgressive lines expressing greater dehydration tolerance than dehydration tolerant parent Hyogokithanishiki. Therefore nursery box method is proposed as a reliable method for the evaluation of dehydration tolerance of rice cultivars and this method is suitable for evaluating germplasm collections and breeding populations for dehydration tolerance in rice breeding.