Wheat kernel dimensions: how do they contribute to kernel weight at an individual QTL level?
Kernel dimensions (KD) contribute greatly to thousand-kernel weight (TKW) in wheat. In the present study, quantitative trait loci (QTL) for TKW, kernel length (KL), kernel width (KW) and kernel diameter ratio (KDR) were detected by both conditional and unconditional QTL mapping methods. Two related F(8:9) recombinant inbred line (RIL) populations, comprising 485 and 229 lines, respectively, were used in this study, and the trait phenotypes were evaluated in four environments. Unconditional QTL mapping analysis detected 77 additive QTL for four traits in two populations. Of these, 24 QTL were verified in at least three trials, and five of them were major QTL, thus being of great value for marker assisted selection in breeding programmes. Conditional QTL mapping analysis, compared with unconditional QTL mapping analysis, resulted in reduction in the number of QTL for TKW due to the elimination of TKW variations caused by its conditional traits; based on which we first dissected genetic control system involved in the synthetic process between TKW and KD at an individual QTL level. Results indicated that, at the QTL level, KW had the strongest influence on TKW, followed by KL, and KDR had the lowest level contribution to TKW. In addition, the present study proved that it is not all-inclusive to determine genetic relationships of a pairwise QTL for two related/causal traits based on whether they were co-located. Thus, conditional QTL mapping method should be used to evaluate possible genetic relationships of two related/causal traits.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Taian Subcenter of National Wheat Improvement Center, College of Agronomy, Shandong Agricultural University, Taian 271018, People's Republic of China.
Fa
F
Cui
Anming
A
Ding
Jun
J
Li
Chunhua
C
Zhao
Xingfeng
X
Li
Deshun
D
Feng
Xiuqin
X
Wang
Lin
L
Wang
Jurong
J
Gao
Honggang
H
Wang
D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D004777:Environment; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D007178:Inbreeding; D010641:Phenotype; D040641:Quantitative Trait Loci; D012639:Seeds / Q000235:genetics / Q000254:growth & development*; D014908:Triticum / Q000235:genetics* / Q000254:growth & development
D005819:Genetic Markers