Phenotypic Diversity And Heterosis Utilization Of New Type Brassica Napus In Tibet

The narrow genetic background is the main limiting factor in the breeding of Brassica napus in China.It is an important way to synthesize a new type of Brassica napus by distant hybridization.This research is based on a new type of Brassica napus,which was created by the research group through sexual cross,multiple generations self cross and directional breeding between the local varieties of Brassica juncea and the No.55 representative new type Brassica napus in Tibet were selected for field direct seeding experiment to carry out phenotypic diversity and heterosis utilization research,and to evaluate phenotypic characteristics,diversity level and Heterosis potential of new type Brassica napus in order to enrich the genetic basis of the new type Brassica napus in Tibet and provide new ideas and methods for breeding of the new type Brassica napus.The main experiments and results of this study are as follows:1 In this study,23 quality characters and 23 quantitative characters of 55inbred lines of Tibet new type Brassica napus were investigated.23 quality traits are mainly related to the botanical characteristics of stems,leaves,flowers,pods and other organs,among which 9 phenotypic traits,such as cotyledon shape,heart leaf color,leaf margin shape,leaf tip shape,stem diameter,leaf shape,corolla size,petal shape,petal bearing state,Podocarpus bearing state,have higher diversity index than 1,and the other phenotypic traits have lower diversity index;23 The diversity index ranged from 2.63 to 2.92,which showed high diversity.Based on 46 characters,55 new type Brassica napus in Tibet were divided into four groups with different phenotypes,among which group 1included 27 lines,which had short growth period,relatively short plant,poor yield and quality characters;group 2 included 19 lines,which had short flowering period,medium plant characters,medium yield and quality characters;group 3 included 8 lines The fourth group contains only one strain XZ47,which has a long growth period,a large plant and vigorous nutrition growth,and the yield and quality characters are better than other groups.2 Twenty five phenotypic characters,including eight yield characters,seven quality characters and ten agronomic characters,of 55 new type Brassica napus in Tibet were identified.The average growth period of the new type of Brassica napus in Tibet is 119.13 days,with a range of 102-125 days.The whole shows the characteristics of precocity;The average plant height was 148.83cm,with a range of 120.64cm-188.36cm,.The average diameter of stem is 14.06mm,the range is 10.10 mm to 22.25 mm,The average number of effective branches is7.77 with a range of 4.67-12.33,The average number of secondary effective branches was 10.31 with a range of 3.34-18.67,The main inflorescence was60.07cm in length and 57.32 in pods,which laid a nutritional foundation for the later yield formation.The yield components are 29.8g per plant,27.07 grains per pod,457.10 effective pods per plant,and 3.86g per 1000 grains.The yield characters have obvious advantages,which is 1515.68kg/hm~2of field yield.The range is 668.70kg/hm~2-2664.80kg/hm~2,It is further indicated that the new type of Brassica napus in Tibet has high yield utilization potential.However,the average oil content,erucic acid content and glucosinolates content of the three main quality traits were 44.55%,12.09%and 63.23μmol/g respectively,which had not reached the double low standard and needed further improvement.In order to make a comprehensive evaluation of 55 new type Brassica napus lines in Tibet,the principal component analysis method was used and the comprehensive scores were taken as the evaluation basis:XZ47、XZ49、XZ27、XZ46、XZ24、XZ35、XZ34、XZ26、XZ17、XZ23、XZ37、XZ51、XZ12、XZ30、XZ36、XZ41、XZ16、XZ25、XZ11、XZ33、XZ45、XZ52、XZ19、XZ2、XZ5、XZ6、XZ22、XZ50、XZ53、XZ31、XZ44、XZ54、XZ29、XZ21、XZ43、XZ20、XZ3、XZ4、XZ38、XZ14、XZ39、XZ48、XZ32、XZ7、XZ9、XZ15、XZ55、XZ13、XZ40、XZ8、XZ28、XZ18、XZ42、XZ1、XZ10.According to the correlation analysis of yield per unit and agronomic characters,the most significant or significant positive correlation characters with yield per unit are as follows:yield per plant>height per plant>number of effective pods per plant>number of effective pods per main inflorescence>stem diameter>number of effective branches per time>bud stage stage>number of birth and development days>height of effective branches per time In order to increase production,the number of effective pods per plant and the yield per plant were increased.3 In order to investigate the application potential of Heterosis in new type of Brassica napus.In the experiment,50-1a was used as the female parent,55 new type Brassica napus and 60 common type Brassica napus were used as the male parent,and the yield and agronomic characters of the two populations were compared.The results showed that the hybrid F1 plants of the new type of Brassica napus were strong,with more branches and flourishing growth;the hybrid F1 plants of the common type of Brassica napus were higher,with longer main inflorescence but less branches,with better heterosis in different plant types of the two groups.The comparison of yield characters showed that the new type of Brassica napus was superior to the conventional type of Brassica napus hybrids in plot yield,yield per plant,number of effective pods per plant,1000 grain weight and other characters,and had obvious yield advantage,which indicated that the new type of Brassica napus had strong utilization potential in yield.