Prescreening rice for cold tolerance at the reproductive stage using anther length (prescreening rice reproductive-stage cold tolerance)

Abstract

Breeding cold-tolerant rice cultivars can reduce the yield loss caused by spikelet sterility induced by low temperatures. This requires facilities that can maintain a precise low temperature, but their limited availability creates a bottleneck for efficient breeding of new cultivars, especially in developing countries. Here, we hypothesized that quantitative trait loci (QTLs) associated with anther length under non-stress conditions could be used to prescreen candidate cultivars for cold tolerance. We tested this hypothesis using two recombinant inbred lines (RILs) based on crosses of a common cultivar, ‘Hitomebore’, with ‘Sasanishiki’ (the “SH-population”, 188 lines) and with ‘Moukoto’ (the “MH-population”, 216 lines) at two N levels. We detected three QTLs related to anther length (on chromosomes 7, 8, and 11) in the SH-population and four QTLs (on chromosomes 1, 6, 7, and 9) in the MH-population. Haplotype analysis confirmed that the spikelet fertility of the RILs that had QTLs for anther elongation was significantly higher than that of RILs that lacked these QTLs in both populations in a cold tolerance test in a cool-irrigation facility. Our results therefore indicate that anther length can be used to prescreen accessions for their cold tolerance during the reproductive stage.