Genetic and genotype x environment interaction effects from embryo, endosperm, cytoplasm and maternal plant for rice grain shape traits of indica rice

A seed genetic model with embryo, endosperm, cytoplasmic and maternal effec ts and genotype x environment (GE) interaction effects was used for analyzi ng ratio of length-to-width (RLW) and ratio of length-to-thickness (RLT) of indica rice (Oryza sativa L.). A factorial mating design in two environmen ts was conducted by including nine cytoplasmic male sterile lines (A) and f ive restorer lines (R) along with their F-1 (A x R), F-2, reciprocal RF2 an d BC1 (A x F-1). RLW and RLT were found to be controlled mainly by genetic main effects, but also by GE interaction effects. Variance of maternal effe cts was larger than other variance components. Variance due to embryo effec ts and embryo x environment interaction effects could also significantly af fect the rice grain shape traits. The total narrow-sense heritability for R LW and RLT were about 85.6 and 69.9%, respectively, with the general herita bilities being 62.5 and 61.9% and the interaction heritabilities being 23.1 and 7.9%. It was suggested by the predicted genetic effects that Zhexie 2, Xieqingzao and Cezao 2-2 were better than other parents for improving rice grain shape traits. (C) 2000 Elsevier Science B.V. All rights reserved.