Studies On Physiological Characters Of Yellow-seeded Canola With High Oil Content

High-yield,high-oil and high-quality canola with reasonable fatty acid composition has always been the goal of canola variety breeding.The quality of canola is related to seed coat color.Compared with other canola,yellow-seeded canola has high-oil and highyield,and the feedability of its rapeseed meal are also high.In this study,the germplasm resources of yellow cultivar "Sichuan Yellow Seed" of Brassica juncea and its near isogenic lines,black cultivars of Brassica napus,and yellow and black near-isogenic lines of Hybrid Progenies from Brassica juncea and Brassica napus were used as materials.The plant growth and development and agronomic traits of different cultivars and different colors of rapeseed,such as 1000-grain weight,fresh siliques weight,fresh seed oil content,fatty acid content and plant hormone content of canola seeds of different varieties(lines)were analyzed to study the biological characteristics of Yellow-seeded Rapeseed with high oil content,and reveal the physiological rules of seed development,oil accumulation and regulation of Yellow-seeded canola.The main results are as follows:1.Yellow-seeded Brassica napus has slender plant stature,with smaller flowers and leaves than Brassica napus,and its silique shape remains basically unchanged in about 25 days.The fresh weight of siliques in Yellow-seeded Brassica napus is significantly higher than that of Brassica juncea,and their plant is stronger and yield is higher,so it is easier to cultivate than that of Brassica juncea.2.No pigments were produced in canola seeds at the early stage of development until the middle and late stages of development,that is,there was a small amount of pigments in the hilum part of Brassica napus at 20 days after pollination.Until 25 days after pollination,the whole seed coat of Brassica napus had pigments,while the black seed coat of Brassica juncea began to produce pigments 25 days after pollination.Proanthocyanidins are the key pigments affecting seed coat color.The content of proanthocyanidins in black-seeded rapeseed is about 30 times that in Yellow-seeded rapeseed,and the content of pigments in black-seeded rapeseed is higher than that in Yellow-seeded rapeseed.3.The oil content and 1000-grain weight of Sichuan yellow seed and its nearisogenic lines,black varieties of Brassica napus and yellow and black varieties ofBrassica juncea hybrids at different seed development stages were significantly different in different colors of canola seeds,and the Brassica napus was higher than that of Brassica juncea,and the yellow-seed rapeseed was higher than that of black-seed rapeseed.4.Oil content and unsaturated fatty acids accumulate gradually with the development of seeds.The content of most fatty acids in rapeseed does not change after about 40 days of seed maturity.The accumulation of most fatty acids in rapeseed is similar,but the change of linolenic acid is opposite according to seed coat color.The content of oleic acid and linoleic acid in yellow-seeded rapeseed is higher than that in black-seeded rapeseed,and the content of palmitic acid in black-seeded rapeseed is higher than that in Yellowseeded rapeseed.5.The content of plant hormones(ZR,IAA,ABA)in rapeseed seeds gradually accumulated with the development of seeds and reached the maximum at about 20 days after pollination,then began to decrease until about 40 days after pollination,and the variation law was similar.There were significant differences in the content of ZR,IAA and ABA.The contents of ZR,IAA and ABA in yellow-seeded rapeseed were higher than those in black-seeded rapeseed from 15 to 25 days after pollination.It indicated that higher concentrations of ZR,IAA and ABA in the early and middle stages of grain development were beneficial to the accumulation of oil and increase of canola yield.