Genetic Analysis Of Important Agronomic Traits Using Three RIL Populations In Upland Cotton

In this study,Lumianyan 28,which has been widely grown in commercial production in recent years,was used as the parent to hybridize with three high-quality American cotton materials Acala 73002,73003and 73009,respectively,to produce three F₂ populations.Each F₂ population was self-pollinated for four generations,resulting in three stable recombinant inbred populations?RILs?,which are Lumianyan28×73002 RILs,Lumianyan 28×73003 RILs,and Lumianyan 28×73009 RILs.The three RIL populations were grown in two locations in the Yellow River Valley—Anyang,Henan Province?E1?and Xingtai,Hebei Province?E2?,and two locations in the Northwest Inland Cotton Region—Alaer,southern Xinjiang Province?E3?and Shihezi,northern Xinjiang Province?E4?,in 2017.Correlations,variances,heritabilities and principal component analysis were estimated for five yield and its component traits,include boll weight,lint percentage,yield per plant,boll number,yield per plant,yield per unit area;five fiber quality traits,include upper half mean length,breaking strength,micronaire,uniformity index;four plant achitecture traits,include plant height,height of the first fruiting branch,the number of fruiting branches,mean inter-node length.Finally,a total of 14 RIL lines were selected from the three RIL populations,which meet the criteria of high-quality cotton in the four environments with extensive adaptability.This study will provide a good reference for breeding for new cotton cultivars with high fiber quality.The main results are as follows:1.Consistent correlations in the same directions were detected for correlations of 11 traits detected in the three RIL populations across the four locations.The following traits were positively correlated:boll weight and yield per plant,boll number and yield per plant,boll number and yield per unit area,yield per plant and yield per unit area,upper half mean length and breaking strength,plant height and height of the first fruiting branch,plant height and the number of fruiting branches,and plant height and mean inter-node length.The following traits were negatively correlated:lint percentage and breaking strength,upper half mean length and micronaire,and breaking strength and micronaire.2.The heritability estimates for boll weight,lint percentage,upper half mean length,breaking strength and micronaire were high?about 80%?;the heritability estimates for plant height,height of the first fruiting branch,and uniformity index ranged 40⁶0%;the heritability estimates for yield per unit area,the number of fruiting branches,and mean inter-node length ranged 20⁴0%;and the heritability estimates for boll number and yield per plant were low?about 20%?.3.The three RIL populations and their component population were analyzed by principal component analysis,respectively,principal components which the characteristic value greater than 1 were extracted,including 4 principal components in Lumianyan 28×73002 RIL population,which cumulative contribution rate was 68.789%;4 principal components in Lumianyan 28×73003 RIL population,which cumulative contribution rate was 69.765%;5 principal components in Lumianyan 28×73009 RIL population,which cumulative contribution rate was 78.226%;4 principal components in component population,which cumulative contribution rate was 69.206%.All these principal components contains most of the information about the yield,fiber quality and plant type traits of the corresponding population.4.According to the criteria of high-quality cotton,14 strains with grade A or above in four environments were selected from the three RIL populations,namely No.67 and 74 from the Lumianyan28×73002 RIL population;No.17,36,40,41,50,55,62,109,and 115 from the Lumianyan 28×73003RIL population;and No.20,41,and 92 from the Lumianyan 28×73009 RIL population.Among them,No.67 of Lumianyan 28×73002 RIL population,No.41 of Lumianyan 28×73003 RIL population and No.92 of Lumianyan 28×73009 RIL population reached 30mm or above in the upper half mean length,and30cN·tex^-1 or above in breaking strength,their micronaire in E3 and E4 were between 3.80⁴.35.