Analysis Of Combining Ability Of Purple Heading Chinese Cabbage And Dominant Combination Sel Ection

Selection of superior combination is an important part in breeding,and the determination of heterosis is the main method to select the dominant combination.Compared with other methods of heterosis prediction,using combining ability to predict heterosis is simple and feasible.In this study,15 their parents,12 reciprocal crosses hybrid F1 of purple heading Chinese cabbage and 3 orthogonal combination were used as materials.Analyze combining ability and determine heterosis about15 main horticultural traits such as the plant gross weight,the net weight and purple leaf number and so on.The main results were as follows:1 The results of heterosis determination,heterosis of yield traits were that the advantages of both the plant gross weight and the net weight of leaf heading in hybrid F1 were almost positive for all.There were significant differences between orthogonal crosses and reciprocal crosses in yield.The heterosis betweem same reciprocal crosses hybrid F1 were different among differant hybrid F1.The heterosis difference were greater than 10% in about 3/4 hybrid F1 combination,so the seeds of hybrid F1 should be only collected as two parents respectively,which were suitable for seed production of male sterile.Heterosis of purple traits were that 2 combinations of purple leaf number had positive heterosis.The other were the negative heterosis.Which illustrate that the purple leaf number in different combinations showed over dominance,dominance and partial dominance.The size of the purple head all showed negative heterosis obviously.The results showed that the purple head size was partial dominance.The heterosis difference were greater than 10% in about 1/4 hybrid F1 combination,and all of them were stronger in orthogonal dominance.Therefore,purple traits may be closely related to cytoplasm.2 The results of combining ability analysis,combining ability of yield traits were that the GCA of parent 13S156,14S460 and 15S448 showed higher positive effect on the gross weight and net weight per plant.The SCA of hybrid combination BA,AC,AD,AI showed higher positive effect on the gross weight and net weight per plant.Combining ability of purple traits were that the GCA of parent 12S165,15S1063,15S1080 and 15S491 showed higher positive effect on the number of purple leaf traits.The SCA of BD,AI,AJ showed higher positive effect on the number of purple leaf traits.3 For heterosis of yield traits,better combinations were BA,AD,FA,AH,HA.For heterosis of purple traits,better combinations were BD,AJ,JA,AI.The yield and purple traits were combined as the main breeding objective,and comprehensively consider disease resistance and maturity,the excellent combinations were BA,AD,FA,AJ.4 The results of correlation analysis of different horticultural characteristies,the correlation between the yield of purple heading Chinese cabbage and the net weight per plant,the weight per plant,the plant width,the thickness of leaf rib,the width of the largest outer leaf,and the width of leaf rib was significant,but the correlation between the yield of purple heading Chinese cabbage and the length of the largest outer leaf was not significant.The correlation between the number of purple leaf and plant width,the weight per plant,the width of the largest outer leaf,the width of leaf rib,the thickness of leaf rib,the net weight per plant,and width of plant head was extremely significant,but the correlation between the number of purple leaf and plant height,the length of the largest outer leaf,the number of outer leaf,leaf rib length,height of plant head,number of head leaves,and Shortening stem length was not significant.