Genetic dissection of seed yield and yield-related traits in grown with contrasting nitrogen supplies.

Unlabelled: Oilseed rape () is the main oil crop in China as well as in the world. Nitrogen (N) deficiency significantly reduces the seed yield of . However, a very few studies involved in the genetic mechanism of seed yield and SY-related traits of in response to N deficiency. In this study, plant height (PH), branch number per plant (BN), pod number per plant (PN), seed number per pod (SN), 1000-seed weight (SW), and seed yield per plant (SY) were investigated using a double haploid (TNDH) population derived from a cross between cultivars "Tapidor" and "Ningyou7" grown at an optimal N (ON) and a low N (LN) supplies in three-year field trials. Great variations of SY and related traits were observed in TNDH population under contrasting N supplies. A total of 106 and 110 significant quantitative trait loci (QTLs) were detected for six traits at ON and LN in three field trials, respectively. All of these significant QTLs for the same trait identified in two or three trials were integrated into 20 stable QTLs. A total of 50 consensus QTLs and 53 unique QTLs were obtained from 172 significant QTLs and 20 stable QTLs, including 35 ON-specific QTLs, 29 LN-specific QTLs and 39 constitutive QTLs detected at both ON and LN. was integrated from four QTLs for PN, PH, SN, SY at LN, was integrated from QTLs for BN, SY, PN at ON and LN. Both and were detected in three trials. In addition, a total of 194 epistatic interactions, inculding 15 pleiotropic epistatic interactions, were identified. Eight of the 15 pleiotropic epistatic interactions were detected to affect SY. This result may help to better understand the genetic mechanism of yield traits in response to low N and promote the breeding of N-efficient varieties.

Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01281-0.