Analysis Of Combining Ability And Heritability Of Several Indica Hybrid Rice Combinations In Early And Late Seasons

In this study,five restorer lines and five CMS lines were used as parental materials.25 F₁ hybrids were developed and planted based on the incomplete diallel design in the early and late seasons of 2016.The phenotypic values of quality traits,the genetic parameters and the combining ability of the F1 hybrids planted in both seasons were analyzed and compared.Thus,we can get a more comprehensive understanding on the information of inheritance and combining ability of the grain quality traits about our research materials,in order to provide insight into future rice quality improvement and breeding.The main findings are as follows.1.The GC,AC,MRL,MRW and MLWR were not significantly differentinphenotypic value of the traits made between the early and late season.The rice quality of the late season was better than that of the early season,mainly due to the increase of the HRR and the reduction of the PGWC and DEC.2.In terms of the results,the GC and AC,mainly affected by additive effect,had high broad and narrow-sense heritability.Although the role of CMS lineswas greater than the restorer lines,the impact fromrestorer lines cannot be ignored.MLWR,MRL and MRW also had high broad and narrow-sense heritability,and they are mainly affected by gene additive effect.In addition,the relative genetic contribution from the CMS lines was much greater than that of the restorer lines.Therefore,the improvement of many traits was mainly based on the selection of the excellent CMS lines.The results of the PGWC and DECwere not exactly the same between the early and late seasons;while the CMS lines had slightly greater effect than the restorer lines.The milling quality with poor genetic stability was susceptible to the environment.Both BRR and MRR,mainly affected by additive effect,were affected by the CMS and restorer lines.While HRR was mainly affected by the CMS lines.3.There was a significant negative correlation between GC and AC in both seasons.The higher the ACresulted in harder GC and worse grain quality.In addition,the decrease of chalkiness increased the HRR.4.The TCA value of the two seasons was positively correlated with the phenotypic values of the quality traits,and almost all of the correlation coefficientswere all above 90%.It indicated that the combining ability on grain quality could be evaluated well using the TCA value.5.In this study,the hybrids derived from Huazhan or G RuanhuaA were found to show better grain quality in both seasons.In addition,the hybrids derived from Hanghui1179 in the early season and that derived from Hanghui1198 and WufengA in the late season also showed good grain quality.Based on the SCA of the hybrids,the superior combinations were TianfengA×Hanghui1198,C815S×Huazhan and WufengA×Hanghui1179.Except the slightly higher SCA of the amylose content,other traits were improved.The hybrids,such as TianfengA×Guanghui128,C815S×Huazhan,WufengA×R273 and C815S×Hanghui1179,performed well relatively in the late season.