Title: Evaluation and introgression of important characteristics related to water-deficit/drought tolerance from tolerant lines into Iranian selected rice cultivars
Author: Ali Moumeni
Water-shortage and drought stress are major challenges in sustainable rice production in Iran. Hence, to evaluate selected rice genotypes, development of breeding populations, and introgression of important morphologic, physiologic, and agronomic characters related to drought tolerance from tolerant genotypes to Iranian popular rice cultivars, this research was carried out in several activities at field and greenhouse during 2015 to 2020 at the Rice Research Institute of Iran, Amol. In the first activity, 22 diverse rice genotypes which were tested at a field experimental site showed significant reductions for different traits such as plant height, number of panicles, panicle length, number of filled grains, 1000 grain weight, relative water content, plant fresh and dry weights, while days to 50 % flowering and non-filled spikelet showed significant increases. According to the results, three rice genotypes with tolerance and susceptibility to drought stress, namely Tarom, Neda, and IR78908-193-B-3-B were selected and tested in a PVC tube at the greenhouse. Results indicated that drought stress treatment affected all traits negatively, except for canopy temperature. It was also found that several genotypes such as Neda, Vandana, AR2, and promising lines i.e. AHS, AN74, and DAH showed better performances against drought stress for days to 50% flowering, grain yield, relative water content, SPAD, and canopy temperature at reproductive stage. Greenhouse test data analysis indicated that two tolerant genotypes i.e. Neda and AR2 showed significantly higher root dry weight, root volume and length, as well as plant dry weight than susceptible genotypes i.e. Tarom-mahali. In the meantime, RWC, SPAD and chlorophyll a and b content were higher in susceptible genotypes. Hence, these genotypes and breeding populations/ lines potentially are suitable to apply in drought-affected areas and aerobic conditions. The resulted breeding populations could be further tested to select suitable lines for the drought-prone areas.
Keywords: Canopy temperature, relative water content, root characteristics, drought stress, rice