Study On Heredity Of Quantitative Characters And Breeding Of New Variety In Seedless Watermelon

12seedless watermelon high-generations inbred divides into2groups,6paternal and6maternal.The species of12seedless watermelon of36combinations and13quantitative traits, do the combiningability analysis, heritability analysis,genetic principal component analysis and genetic distance analysis.Screen out the better, in conclusion, confirm the new seedless watermelon combination—M5×A1.Primary research results as following:1、Tested on12parents,analysis of variance of the13agronomic traits of36combinations showthat the difference is not obvious between groups,but quite clear between crosses of13agronomic traits.2、Tested on heritability analysis of12seedless watermelon of13agronomic traits show that thethick of pathway,the length of burl,the weight per fruit,lengthways span,transverse span,the index offruit,the content of side soluble solids,the content of centeal soluble solids,organic acid,vitamin C, tothese10traits, their parents fit for heterosis breeding from the breeding point of wiew.In addition,thelength of tendril and pulp thickness,to these2traits,the proportion of general combining ability varianceand specific combining ability variance are about50%,it should consider the two kinds of combiningability to choice parents.3、From the measuring13traits,group heritability analysis of each agronomic trait show thatbroad-sense heritability is always90%above, narrow-sense heritability is always below50%,except thenarrow-sense heritability of the main stem.4、According to the comprehensive evaluation of each parent, the general combinging ability of the6male parental lines was A1>A2>A6>A5>A4>A3.The general combinging ability of the6femaleparental lines was M5>M4>M6>M2>M1and M3.5、Tested on genetic principal component analysis of13agronomic traits show that first, fifth andseventh principal components are moderate,that is,the index of fruit and lengthways span,the content ofside soluble solids and the content of center soluble solids,pulp thickness are moderate.The third,forthand sixth principal components are too small,that is,the length of burl,transveres span,the content ofcenter soluble solids and the content of vitamin C are too small.The second principal component is toolarge,that is, the index of fruit and the weight per fruit is too large.6、Tested on genetic distance analysis of36combinations show that the value of combinationM1×A6is maximum,it is1.2526,the value of combination M2×A6is minimum,it is0.5402.Fromheterosis we can see that different seedless watermelon parents performance different advantages,different advantages are expressed by different seedless watermelon parents,it is difficult to filter outdifferent traits parents of heterosis. The way of breeding pairs should change gemination hybridizationto the complex hybridization. 7、Tested on linear regression analysis of genetic distance and heterosis show that the relationshipof genetic distance and the value of pro-parent heterosis of central sugars,organic acid,vitamin C haslinear regression.Correlation coefficient,regression coefficient,regression equation has reached asignificant level.8、Tested on non linear regression analysis of genetic distance and heterosis show that therelationship of genetic distance and the weight per fruit,fringe sugars,lycopene is consistent with theDensity model, the coefficient of determination, regression equation is significant.9、Tested on the relationship of genetic distance and heterosis show that the relationship of geneticdistance and heterosis may be linear,may be nonlinear.This is depending on the range of geneticdistance.