Mapping And Analysis Of QTLs Associated With P Nutrition Efficient In Brassica Napus Using Molecular Markers

Rapeseed is one of the major oilseed crops in China, contributes to about 50% of the vegetable oil consumption, planting area and gross product is the first in the world. Brassica napus was sensitive to phosphorus deficiency and had a wild genetic diversity. It was necessary and practicable to genetic improve phosphorus deficiency in Brassica napus. 256 Brassica napus cultivars were collected and screened for P sensitive difference by Laboratory of Microelement in HuaZhong Agricultural University with pot cultures. A representative P efficient cultivar's "97081" and a representative inefficient cultivar's "97009" were found, and then confirmed further by field experiment. A framework genetic map was constructed from a F23 population derived from a cross between the P efficient cultivar's "97081" and the inefficient cultivar's "97009" with molecule markers of SSR, AFLP and so on in the this study. The main results are as follows:1. A total of 202 SSR and AFLP multipoly markers were used to construct a sparse genetic linkage map with 23 linkage groups covering approximatelyl950.7 cM with an average spacing of 9.66 cM. At the same time, the lower frequency partial separation was observed, the ratio 15.5%, the main region of partial separation occurred on the linkage LG2 and LG13, the universality of partial separation was further discussed.2. 45 trait relative markers were screened by chi-square test in single factor method in the P<0.01 level totally. Among them, at most 27 markers were discovered under the P deficiency condition, accounted for 5.0 %-10.9% of the total variation, cluster on LG11andLG12.3. By the method of Composite Interval mapping, the six traits were QTL mapping, including yield, plant height, branch number, first branch height, upper dry weight and thousand seed weight under normal P and deficiency P condition. 28 QTLs were detected, The phenotypic variance explained by those QTLs ranged from 7.7%-59.2%; QTLs of different trait including the P efficiency gene QTL dsy2, dsy3were overlapped in the Confidence Interval of LG3, LG11 and LG12 linkage. dsy1, dsy2, dsy3 and pecl were conformed the P efficiency gene . the variation explained by each component were 39.4%, 37.5%, 19.4% and 41.4%. respective dsy1, dsy2 and peciwere the object of further QTL research.