Studies On Hereditary Characteristics Of Early-maturing Varieties In Rapeseed (Brassica Napus L.)

Early muturity oilseed cultivation has adjusted the season contradiction between double cropping rice in the area of rice-rice-rape.In order to understand genetic basis about early maturity in Brassica Napus. In this paper, we have analysed its growing period, agronomic traits, quality traits and yield respectively.Also designed the staging sowing test of different sources of early maturing variety.In addittion. the F2population was abatined from F1crossing between earlyxmid-late mature seed material.After genome scanning. SSR marker based genetic linkage map have been constructed.The main results are as follows:1、The whole growth period of early varieties have last as long as180days. Generally.active accumulated temperature of early varieties is1500degrees Celsius.With the delaying of sowing date, the whole growth period was gradually shorten.Whille Sowing earlier, it is prone to early flowering phenomenon and affect the yield.However.it would not appeare early flowering when the early maturity variety was sowed after the mid of October..We concluded that seeding period of early-mature winter rapeseed should be the mid of October.With the delaying of sowing date, the flowering period was gradually shorten.Based on the analysis between different growth period and mature period.we have obsearved that the correlation coefficient between final flowering and maturity is maximum. Thus, it coulde be selected as the time final flowering of early maturity varieties time as a basis.2、With the delaying of sowing date, plant height gradually reduced.In addition,nodes on main stem and branch number was gradually decreased.The number of pods per plant, grain number and grain weight per fruit affects the yield of rape directly. With the delaying of sowing date, the number of pod and weight per plant were reduced. However, sowing on October25th most early variety the characters have obvious advantages. Delaying of sowing date, the numeber of silique per plant have little change.Therefore, sowing the early varieties of oilseed rape in the mid or late of October can be in favor of seed yield formation.3、The oil content had no significant difference in sowing period. Sowing in the middle of November.the oil content in the seed will decrease.it showed that the sowing date hnve little effect on oil content.However, other characters in different sowing period of have been found some differences.4、In this study, the F2population was used for genetic map construction. A total amount of1008primer paires have been detected the polymorphism between parents and F1hybid.Consequently, there are224pairs of primers amplified products between the parents and the ratio of polymorphism is22.2%.Finally, there are22markers can be allocated in7different linkage groups, while the total length of the genetic map is229.6cM. average each linkage group32.8cM. the average spacing of10.45cM markers.