Analyses Of Heterosis And Combining Ability In Major Yield & Quality Traits Under Different Environments In Brassica Napus L.

30 reciprocal crosses were made with 6 Brassica Napus L.lines different,based on the Griffing Model I design.Branch height,branch position,primary branch number,effective number of pod,number of grain per pod,1000 grain weight,yield per plant,oil content and protein content,etc nine yield and quality trait of a total of 36 accessions including the 6 parent lines were evaluated the main search result of heterosis combining ability and corresponding analysis under different environment showed as follow:1.The heterosis analysis result of yield trait indicated that there is significant heterosis in yield trait of Brassica Napus L.of single-plant yield and effective number of pod was bigger,but little mid-parent heterosis of number of grain per pod and 1000 grain weight in yield of single plant and three main factor of yield.There also were the similar results in over-parent heterosis.In other traits mid-parent heterosis of branch position was biggest,then height,last primary branch number and traits over-parent heterosis of height was biggest.Corresponding analysis of heterosis of Trait under two environment indicated that mid-parent and over-parent heterosis of the observed trait in two environment existed significant or extremely significant level. Correlated heterosis between effective number of pod and yield per plant was the largest.The analysis result of heterosis of oil content and protein content show that totally oil content exhibited some mid-parent and over-parent heterosis but not for protein content trait.The correlated analysis result indicated that there were significant correlations between heterosis of two different environments in oil content trait but little correlation in protein content.2.The analysis results of united variance of combining ability show that general combining ability,special combining ability,reciprocal effect,environment effect general combining ability by environment,special combining ability by environment of all trail excluding reciprocal effect environment effect reciprocal by environment effect of primary branch number were highly significant.The stability analysis of combining ability showed that stability coefficient of general combining ability of 1000 grain weight and yield per plant was great than 80%,only stability coefficient of general combining ability of number of grain per pod and protein content was less than 50%.Stability coefficient of special combining ability of 1000 grain weight and yield per plant was great than 80%,only stability coefficient of general combining ability of effective number of pod and 1000 grain weight was less than 50%.For stability coefficient of reciprocal effect,excluding primary branch number,yield per plant and oil content,existed great coefficient others less than 50%.3.Estimation of component of variance of combing united variance show thatσ~2 CGA of oil content and protein was great thanσ~2 SGA butσ~2 SGA of others was bigger thanσ~2 CGA.onlyσ~2 CGA×E of branch position,number of grain per pod,oil content was great thanσ~2 SGA×E not for other traits.4.Analysis result of genetic ability indicated that general ability of primary branch number was 70.02%general ability of single-plant yeild was 82.91%and others all over than 90%.Special genetic ability of 1000 grain weight,oil content, protein content were higher(＞70%) but others were less than 50%.5.Estimate value of combining ability showed that general combining ability (GCA)ofyield of S6R,ZY821 and 3063 under tow environment were higher.GCA of oil content of 3102 and 3063 under tow environment were higher.GCA of protein content of ZY821 and B25 under tow environment were higher.GCA of both yield and oil content of 3063 under tow environment were higher.Under Yaan environment, Special combining ability(SCA) of single-plant yield oil content protein content were highest in these combinations(3603×B25,3102×CG38,B25×ZY821) Under Anxian environment,reciprocal effect of single-plant yield oil content protein content were highest in these combinations(3603×B25,S6R×CG38,B25×CG38)6.Analysis result of correlation among traits indicated that the trait which has the highest correlation with single-plant yield was effective number of pod then height under two environments.There were extremely minus correlation between oil content and protein content under two environments.No significant correlation were found among other yield traits and oil content or protein content7.Corresponding analysis among combining ability and pro-type observed value of traits and heterosis showed that GCA was highly correlated with pro-type value of traits but SCA were highly correlated with heterosis.