Objective To study combining ability of quality traits of new male sterile lines and new restorer lines of indica hybrid rice.

Method An incomplete diallel design (NCII) was adopted. Four self-bred new male sterile lines and four new restorer lines were combined, and the combinations were planted in the early and late seasons in 2014. The quality traits of these 4×4 combinations were surveyed to analyze their combining ability.

Result Both general combining ability variance and specific combining ability variance were significant at 5% or 1% levels for most traits, the former was larger than the later. The contribution rates of general combining ability variances of male sterile lines were much greater than those of restorer lines regarding head rice rate, chalky rice rate, chalkiness degree, amylose content, etc. Among the male sterile lines, G Ruanhua A was excellent in most quality characters, featuring good general combining ability and great variance of specific combining ability, and had no obvious defects in other characters, so it was an excellent parent. On the other hand, character defects were found in all restorer lines. Nevertheless, Huagandao 3 had many desired traits including brown rice rate, milled rice rate, head rice rate, chalkiness degree and length/width ratio. Huahui 521 had good general combining ability and great variance of specific combining ability in terms of chalky rice rate, amylose content and gel consistency, which made it easier to obtain combinations of suitable amylose content, gel consistency and low chalky rice rate.

Conclusion The quality traits are controlled by both additive and non-additive effects, and the additive effect is more important. The contribution rates of additive effects of male sterile lines are much greater than those of restorer lines regarding head rice rate, chalky rice rate, chalkiness degree, amylose content, etc. However, for length/width ratio and gel consistency, the additive effects of restorer lines are greater.