Preliminary Study On Screening And Application Of Early Brassica Napus L. In Guangxi

At present,given the fact that Brassica napus,introduced and planted after the late rice harvest in Guangxi Zhuang Autonomous Region,cannot be harvested when early rice needs to be raised/transplanted in the following spring and cannot produce direct economic benefits,farmers are less motivated to plant B.napus in the winter fallow fields.In order to make full use of the fallow fields in the Guangxi Zhuang Autonomous Region in winter,improve the multiple cropping index,increase the income of farmers,and lay the foundation for our country to expand the rape planting area in the south and partially solve the problem of the shortage of edible vegetable oil in China,the research group selected and cultivated a new batch of early-maturing B.napus which are suitable for the local climate and environment in Guangxi.In this study,the paper investigates the growth period,agronomic trait,yield and quality trait of these new early-maturing B.napus,and discloses the results of the preliminary study on the heterosis of the configured hybrid combinations and the performance of planting practices in different regions are preliminarily studied.The main results obtained are as follows:（1）In late August,2021,the primary flowering phases of B.napus cultivated by research group in Dinggu village base in Laibin City were reported to distribute among September 26^th and October 25^th,with the B.napus coded 21XZ8-205 enjoyed the earliest primary flowering phase.Generally,it takes 30 days for B.napus to grow from seeding to primary flowering,while the theoretically-shortest mature period is 90-100 days.Besides,there were also 2 varieties of B.napus that had primarily flowered during the National Day.All these are new varieties of early B.napus,which can be planted to forge the flower sea of B.napus during the National Day holiday,avoiding staging as other flower sea of B.napus in March and April in China.Such being the case,the new tourism resource can be forged to uphold rural revitalization.（2）From July to August 2021,a small amount of the above-mentioned early-maturing B.napus hybrid combinations were cultivated at the B.napus Summer Breeding Base in the mountainous area of Quanzhou city,and observed the performance of heterosis in November of the same year.It was found that the primary flowering phase,the highest plant height,effective length of main inflorescence,branch position,total number of branches and the number of effective siliques of 311-2×314-2 were higher than those of their early-maturing male parent 314-2,which was regarded as superparent advantage.Especially given that the hybrid combinations of 311-2×314-2 were 5days earlier than 314-2 from seeding to primary flowering,the number of effective siliques were more than that of 314-2,showcasing the huge potential for heterosis utilization of early B.napus.（3）The varieties-comparison experiment for eight varieties（strains）were carried out by performing three times of repetitive experiments with radom block-groups,including two strains of home-grown early B.napus（356-1 and 383-5）,one regular variety（Sunny 131）,two hybrid varieties（Liyouza 108 and Liyouza 168）and three hybrid combinations（No.1,No.3 and No.4）.According to the date of the primary flowering phase,it was determined that only two home-grown strains of early B.napus356-1 and 383-5 were suitable for planting in the winter fallow fields in Xiangzhou County.According to the investigation on ripeness of siliques on the actual harvest date of April 10^th（one day before the tilth of early rice）,the performance of both 356-1 and 383-5 were better than other six varieties（combinations）introduced from outside the region.It was worth mentioning that the growth stage of the two strains of early B.napus356-1 and 383-5 was earlier than the regular variety Sunny 131,which laid a material foundation for the innovative promotion of the early rice-late rice-rape triple-cropping rotation system in the south of China,but further improvements in yield,quality and oil content would be needed in the future.（4）Based on data obtained by further field investigation and research,it was found that the periods of winter fallow fields in Xixiangtang District of Nanning City,Mashan County of Nanning City,Xashi Town of Pingxiang City,Luobo Township of Guiping City,and Maping Town of Xiangzhou County was raging from 137 to 164 days.Among the early B.varieties（strains）cultivated in the experimental fields of Guangxi University,the period from seeding phase to the primary flowering phase was between 52 and 97 days.To data of March 28,2022,the siliques of new early B.napus strains bred by two research groups were mature,055-3 and 377-3,respectively,with a total growth period of 123 days.The primary flowering phase of 005 in the experimental greenhouse in Dinggu Village,Xiangzhou County in summer was about 35 days,and the primary flowering phase of the hybrid combination may be about 5days earlier than that of the parent.Through the research,it was found that hybridizing the home-grown early-maturing B.napus with other strains with good yield,quality,and oil content for heterosis is an effective way to promote the early rice-late rice-rape triple-cropping rotation system in the south of China.In addition,this study also tries to carry out the research of inter-cropping of B.napus with other economic crops in Guangxi,so as to provide a reference for subsequent large-scale promotion.