Identification and characterization of a high kernel weight mutant induced by gamma radiation in wheat (Triticum aestivum L.)

Abstract

Background: Inducing mutations are considered to be an effective way to create novel genetic variations and hence novel agronomical traits in wheat. This study was conducted to assess the genetic differences between Shi4185 and its mutant line Fu4185, produced by gamma radiation with larger grain, and to identify quantitative trait loci (QTLs) for thousand kernel weight (TKW).

Results: Phenotypic analysis revealed that the TKW of Fu4185 was much higher than that of Shi4185 under five different environments. At the genomic level, 110 of 2019 (5.4%) simple sequence repeats (SSR) markers showed polymorphism between Shi4185 and Fu4185. Notably, 30% (33 out of 110) polymorphic SSR markers were located on the D-genome, which was higher than the percentage of polymorphisms among natural allohexaploid wheat genotypes, indicating that mutations induced by gamma radiation could be a potential resource to enrich the genetic diversity of wheat D-genome. Moreover, one QTL, QTkw.cau-5D, located on chromosome 5DL, with Fu4185 contributing favorable alleles, was detected under different environments, especially under high temperature conditions.

Conclusions: QTkw.cau-5D is an environmental stable QTL, which may be a desired target for genetic improvement of wheat kernel weight.

Fig. 1

Phenotypic comparison of Shi4185 and Fu4185 planted at BJ-2011. a Plants at the filling stage; b Spikes at the filling stage; c Kernels after harvest

Fig. 2

Sequence alignment of Xbarc239 of Shi4185 and Fu4185 with wheat chromosome survey sequence

Fig. 3

Locations of QTL for TKW in the F₂ and F_2:3 populations. QTLs with a LOD value more than 2.0 are shown on the right. The most likely intervals of the loci with LOD from top to 1.0 are shown in black

Fig. 4

Physical map of QTLs for TKW. The most likely intervals or associated markers of the QTL are shown in black