Preliminary Study On Heterosis And Heredity Of Quantitative Characters In Chinese Pumpkin

Thirty six hybrids derived from12inbred lines using NC II design were used toresearch heterosis analysis, analysis of variance, heritability analysis, combining abilityanalysis, principal component analysis, correlation analysis and regression analysis of12quantitative traits in Chinese pumpkin. The main results can be concluded as follows:1.The Chinese pumpkin heterosis universal existence. The length of main vine, singlefruit weight, number of fruit per plant, soluble solid content, polysaccharide content, fruitdiameter and Vitamin C content had significant positive heterosis. Dry matter content hadthe same level between positive heterosis and negative one. The length of burl, β-carotenecontent, fruit length, flesh thickness showed negative heterosis.2.36combinations of which12quantitative characters were used to research analysisof variance. The result showed that variance is not so sisnificant, between the various thecombinations of12traits were shown a very significant difference.3.The length of main vine, soluble solid content, dry matter content had higher narrowsense heritability, and they should be selected in early generations.The length of burl,single fruit weight, polysaccharide content, β-carotene content, Vitamin Ccontent, fruitlength, fruit diameter had lower narrow sense heritability, and they should be selected inmiddle or later generations.4.General combining ability variance for the length of main vine, soluble solid contentand dry matter content were greater than specific combining ability variance. The varianceof general combining ability for the length of burl, single fruit weight, polysaccharidecontent, β-carotene content, Vitamin C content, fruit length and fruit diameter were higherthan that of specific combining ability variance. Number of fruit per plant and fleshthickness of two traits in general combining ability and the combination of specificcombining ability were equally important.5.The general combining ability sequence of female parent was Q1﹥Q3﹥Q4﹥Q6﹥Q2﹥Q5, and that of male parents was B1﹥B3﹥B5﹥B4﹥B2﹥B6. There was noinevitable corresponding relation between parents’ general combining ability and its hybridcombination of specific combining ability.6.The result of principal component analysis showed that the first principalcomponent had the maximum contribution. The first, three, four and seven principalcomponent should be suitable to medium. The two and five principal components can beappropriately large. The six principal components should be small to medium. 7.The Chinese pumpkin were sisnificantly categorized into4groups, and thecomprehensive qualities of group4were the best.8.The result of correlation analysis indicated that the relationship between the lengthof main vine and flesh thickness, dry matter content, β-carotene content was sisnificantcorrelation. The length of burl presented a sisnificant correlation with single fruit weight,number of fruit per plant, flesh thickness. There was high sisnificant or sisnificantcorrelation between single fruit weight and flesh thickness, fruit length, number of fruit perplant, soluble solid content. Sisnificant correlation was found to exist between number offruit per plant and fruit length. The correlation coefficients of fruit diameter and fleshthickness, fruit length was at the sisnificant level. Soluble solid content had very sisnificantor sisnificant correlation with dry matter content, β-carotene content, fruit length. Drymatter content showed a sisnificant or highly sisnificant correlation with polysaccharidecontent, β-carotene content, number of fruit per plant, fruit length. β-carotene content wasof positive correlation with Vitamin C content. So regression equations were constructed.