This study aims to reveal the dynamic changes in leaf SPAD values,and its general combining ability(GCA),genetic effects of South China late-season indica hybrid rice,in order to provide relevant scientific basis for the breeding of high efficient new hybrid varieties of South China.Three indica male sterile lines and six indica restorer lines widely used in South China were used to make 18 incomplete diallel cross combinations.Then,GCA and genetic effects of leaf SPAD values of these varieties at different developmental stages were analyzed.The results showed that the leaf SPAD values of hybrids and its parents showed a gradually decreasing trend after transplanting,reached the lowest point at the panicle initiation stage(43 or 50 DAT),and rapidly decreased at the initial heading stage(60 DAT).There were significant differences in leaf SPAD values between different varieties and the same variety at different developmental stages.Especially,from the filling and fruiting stage to the wax ripening stage,the leaf SPAD values of'Rongfeng A','Wufeng A','Huazhan','Guanghui 308'and their corresponding hybrids decreased rapidly,while that of'Minghui 63','Gui99'and their corresponding hybrids still maintained relatively higher level,which displayed the same trend with the dynamic changes in GCA of their parents'leaf SPAD values.Except for the early tilling stage in which the special combining ability(SCA)of the leaf SPAD value reached 70.76％,the GCA played a dominant role in the leaf SPAD value at all other developmental stages.The heritabilities of leaf SPAD value of hybrids in reproductive growth stage(21.90％-63.89％)were significantly higher than those in vegetative growth stage(8.02％-14.79％).The leaf SPAD value of hybrids was mainly attributed to additive effect,as well as dominant or/and epistatic effects at the same time.The dominant or/and epistatic effects increased from the initial heading stage to the flowering stage,reaching 18.37％and 22.02％,respectively.At the early and middle stages of development,the leaf SPAD value was less affected by environmental conditions,while at the later stage,it was more affected by environmental conditions.
维普
万方数据