| Rapeseed is an important oil crop in China.The continuous improvement of its yield and quality is related to the security of grain and oil in China.Therefore,it is urgent to carry out the collection,conservation,identification and evaluation of rapeseed germplasm resources to explore and utilize a batch of excellent germplasm to broaden the genetic background of rapeseed and improve the yield and quality of rapeseed.In this study,300 core collections of oilseed rape germplasm were used as experimental materials,and 24 agronomic traits were identified during the whole growth period under field conditions.Statistical analysis,difference analysis,correlation analysis,principal component analysis,and cluster analysis were conducted for each trait.The interactions between various agronomic traits were analyzed,their genetic diversities were evaluated,and a series of specific germplasm resources were selected.Key results were as follows:1.Statistical analysis of 300 core collections of oilseed rape germplasm at seedling stage showed that 29.00% germplasms are elliptical leaves and 71.00% are oval leaves.The shapes of leaf margin are wavy in 5.70% of the materials and serrate in 28.30%,and whole in 66.00%.The leaf color of 3.70%,85.30% and 11.00% of the materials are light green,green and thick green,respectively.The growth habits of 48.3% of the material at the seedling stage are upright,6.70% are semi-upright,and 45.00% are creeping.2.The statistical analysis of the growth period characters of 300 core collections of oilseed rape germplasm showed that: During two years,the average growth period of 300 core collections of oilseed rape germplasm is 250 days,while the growth period of Y296 is extremely short at about 120 days.Materials such as Y002,Y153,and Y163 were in the middle,at about 250 days.Materials such as Y130,Y118,and Y011 are relatively late,around 270 days.3.Statistical analysis of yield related agronomical traits of 300 core collections of oilseed rape germplasm showed that: The average number of the whole plant effective siliques of 300 core collections of oilseed rape germplasm is 280 in two years.The numbers of the whole plant effective siliques of Y140,Y160,and Y224 materials are less,about 140.Y187,Y108,and Y196 materials are in the middle,about 315.Y277,Y268,and Y225 materials are more,about 530.The average number of grains per silique of 300 core collections of oilseed rape germplasm is about 25.Materials such as Y237,Y021,and Y046 have fewer grains per fruit,around 12 grains.Materials such as Y104,Y001,and Y039 are in the middle,around 25 grains.Materials such as Y136,Y005,and Y008 have more grains,around 40 grains.The average number of 1000-seed weight of 300 core collections of oilseed rape germplasm is about 4.2 g,Materials such as Y041,Y277,and Y187 have a smaller 1000 grain weight,around 2.4 g,while materials such as Y033,Y150,and Y141 are in the middle,around 4.3 g,and materials such as Y058,Y144,Y059,and Y100 are larger,around 6.2 g.4.Statistical analysis of agronomical traits related to the quality of 300 core collections of oilseed rape germplasm showed that: The average protein content of 300 core collections of oilseed rape germplasm is about 28.00% in two years.The materials of Y056,Y032,and Y220 are less,about 24.00%,Y258,Y102,Y072 are in the middle,about 28.00%,while Y265,Y205,Y204 and other materials are more,about 34.00%.The average oil content of 300 core collections of oilseed rape germplasm is about37.00%,Materials include Y184,Y133,and Y227 have less oil content,about 28.00%,Y066,Y106,and Y187 are in the middle,about 37.00%,while Y199,Y122,and Y240 are more,about 44.00%.5.Differential analysis of 20 numerical agronomic traits in 300 core collections of oilseed rape germplasm showed that: The 300 accessions of core rape germplasm have great differences in agronomic traits.The order of coefficient of variation are as follows:height of the starting effective branching site,number of effective siliques in whole plant,oleic acid content,silique density of main inflorescence,main inflorescence length,number of effective primary branches,grains per silique,gamma linolenic acid content,thousand seed weight,length of silique,palmitic acid content,plant height,linolenic acid content,oil content,initial flowering stage,full-blooming stage,squaring stage,bolting stage,ending flowering stage,protein content,coefficient of variation are48.34%,31.66%,31.59%,29.52%,26.49%,25.76%,24.08%,18.60%,18.38%,15.78%,14.63%,13.63%,11.33%,9.14%,8.07%,7.67%,7.08%,7.08%,6.19%,6.00%.The results showed that 300 core collections of oilseed rape germplasm have rich variation types,indicating that these materials can provide a material basis for the rape breeding with different breeding objectives.6.Through statistical analysis and comparison of phenotypes,ten excellent germplasm materials,including Y006,Y008,Y091,Y093,Y096,Y106,Y112,Y180,Y193,Y256,Y261,Y266,and Y296,were selected for subsequent rape germplasm innovation.7.Genome-wide association analysis were carried out on 300 core collections of oilseed rape germplasm.Fifteen candidate genes related to rapeseed 1000-seed weight traits,such as Bna A09g19730 D,Bna A09g19740 D,and Bna A09g19770 D,were screened,as well as 16 candidate genes related to rapeseed oil content traits,such as Bna A02g09070 D,Bna A02g09100 D,and Bna A02g09120 D,providing a reference for subsequent research on rapeseed functional genomics and molecular breeding.In this study,the extreme traits and ten materials with excellent comprehensive traits were selected through phenotypic identification and germplasm evaluation of 300 core collections of oilseed rape germplasm.Based on these,several candidate genes related to 1000-seed weight and oil content were screened using genome-wide association analysis,laying a foundation for subsequent functional genome research and molecular breeding of rapeseed. |
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