Genotype x environment interactions for chilling tolerance of rice recombinant inbred lines under different low temperature environments

Chilling injury is one of the major environmental stresses in rice cultivation in high-latitude and high-altitude regions. In this study, we cultivated a set of recombinant inbred lines (RILs) derived from Milyang 23 (indica)/Tong 88-7 (japonica) crosses in Kunming (high-altitude location), Yanji (high-latitude location), Chuncheon (cold water irrigation), and Suwon (normal) to evaluate the genotype x environment (G x E) interactions for chilling tolerance. RILs were the most severely damaged under the natural chilling air temperatures in Kunming. Significant G x E interactions in all measured agronomic traits were detected, and thus, the additive main effects and multiplicative interaction (AMMI) statistical model was applied to dissect the G x E interactions. The biplots of grand mean and IPCA1 (interaction principal component axes) of chilling-related traits accounted for most of the total treatment sums of squares. The IPCA scores of spikelet fertility and phenotypic acceptability were relatively smaller in Chuncheon than in Yanji and Kunming, implying that the screening for chilling tolerance with cold water irrigation in Chuncheon was more stable, whereas the Yanji and Kunming plantings were more sensitive to G x E interactions for chilling tolerance. These results demonstrate that multi-locational screening should be the best strategy for developing widely adaptable chilling-tolerant varieties in rice.