QTL Mapping Of Seed Dormancy And Growth And Development Related Agronomic Traits In Brassica Campestris L.ssp.chinensis Var.

Brassica rapa(2n=20,AA)is a species of Brassica which is an important crop,including vegetables,oilseeds and forage crops.A variety of crops are widely grown as leafy vegetables in China,South Korea and Japan,and in India,China and Canada are used for the production of vegetable oils and in Europe as feed crops.Chinese cabbage,pakchoi and turnips belong to different morphological types of different subspecies.In this study,QTLs for seed dormancy and growth and development related agronomic traits were mappeded based on Chinese cabbage-caixin chromosome segment substitution lines(CSSLs).The main results are as follows:1.Based on the preliminarily constructed Chinese cabbage-caixin CSSLs,combined MAS technology to perfect CSSLs and obtain a set of CSSLs with 75 lines that are basically complete.Lines with single substitution fragment are 66,double substitution fragments are 9.The total insert segment length is 458.27 Mb,the target segment insert length is 208.46 Mb,the genome coverage rate is 81.02%,and the caixin genome recovery rate is 98.06%.2.The dormancy identification and QTL mapping of Chinese cabbage-caixin CSSLs population were performed.12 QTLs related to seed dormancy were detected in three biological replicates,respectively located at A01,A02,A03,A04,A05,A06,A09 and A10,and were respectively named q D-1-1,q D-1-2,q D-2-1,q D-3-1,q D-3-2,q D-3-3,q D-4-1,q D-5-1,q D-5-2,q D-6-1,q D-9-1 and q D-10-1.And with matching homologous genes on arabidopsis,27 dormancy related genes were obtained,which provides basis for fine mapping and gene cloning studies.3.In summer 2017 and autumn of 2017,QTL mapping of agronomic traits was performed using 75 Chinese cabbage-caixin CSSLs populations.One-way analysis of variance(ANOVA)was used to analyze the significant differences between the CSSLs and the recurrent parent ?49 caxin?.Finally,a total of 157 QTLs were detected on 10 linkage groups,which 11 QTLs controlling plant height,22 QTLs controlling the plant diameter,10 QTLs controlling days to bolting,11 QTLs controlling days to flowering,14 QTLs controlling leaf length,and 11 QTLs controlling the leaf width,8 QTLs with petiole length,11 QTLs controlling petiole width,15 QTLs controlling flowering stalk diameter,12 QTLs controlling wax on flower stalk,14 QTLs controlling leaf surface flatness,11 QTLs controlling leaf color and 7 QTLs controlling leaf division.Among them,there were 32 QTLs stably expressed in two replicates.