| Chinese cabbage(Brassica rapa ssp.chinensis)is a cruciferous Brassica leaves with vegetables.Chinese cabbage is one of the largest vegetable crops in China,occupying an important position in the national diet.Its cultivated area and consumption are the first in all kinds of vegetables in China.Heterosis is a widespread genetic phenomenon,referring to the genetic structure of the two groups produced by the hybrid F1 in the production potential,viability,reproductive capacity and adaptability is superior to parents or more than two parents.It has been successfully used in many kinds of plants and animals,as the heterosis is a quantitative genetic phenomenon,often involving complex genetic network regulation,and by environmental factors,the genetic mechanism of heterosis has not been fully understood.Based on the classical theory and hypothesis of heterosis genetic basis,this paper makes a systematic study on the heterosis mechanism of Mosaic cabbage(Brassica juncea).By analyzing the field traits and photosynthesis and the relative activity of some oxidases,the heredity of heterosis of Chinese cabbage was elucidated,which laid an important foundation for further analysis of the heterosis mechanism and application of Chinese cabbage.Below are key research findings:1)Field performance measurements revealed that the hybrid generation of the split-leaf cabbage hybrid was superior to the parent and had a high uniformity,with traits such as leaf number,root length,leaf length,leaf width,aboveground fresh weight,and underground fresh weight.The parental probabilities were all greater than zero,the heterosis index was >1,and the positive advantage was obvious.2)The photosynthetic index determination found that the heterozygous superiority of the net photosynthetic rate,transpiration rate,stomatal conductance and water use efficiency of the hybrid generation materials was greater than zero,indicating that the heterogenous material had stronger photosynthetic and carbohydrate than the parent material.Accumulation and water use efficiency are high,which is the physiological basis of the yield advantage of the hybrid generation material.3)The relative activities of antioxidant enzymes were measured.It was found that SOD activity,POD activity and CAT activity of hybrid generation materials were higher than those of the parent materials,indicating a positive advantage,indicating that the hybrid generation may have strong resistance to stress,strong growth potential,and yield advantages.The guarantee.4)Trait correlation analysis found that the yield and number of leaves of Chinese cabbage,maximum leaf length,fresh weight of above ground,maximum root length,plant width,Sod,Cat,Pod correlation,and the underground part of the fresh weight correlation,However,the correlation with the maximum leaf width was not significant.5)Four hybrid generations of materials 15HF4,15HF5,15HF8,15HF9 can be used as demonstrations for the promotion of new varieties. |
