Discovery of novel genes for improving protein quantity and grain texture by marker-mediated genetic analysis

Abstract

A series of precise genetic stocks of wheat were investigated to discover new, novel loci controlling grain texture and protein quantity, and grain size and shape, which would be of use for directed plant breeding by marker-assisted selection.

Analysis of a population of Hobbit Sib (Avalon 5A) recombinant substitution lines revealed two year-on-year consistent loci associated with both protein content and texture, although these were not statistically significant.

Analysis of Hobbit Sib (Avalon 5D) recombinant substitution lines revealed strong consistent associations, as expected, between the hardness locus, Ha, and grain texture, and between a quantitative trait locus (QTL) on the long arm and grain protein content. Both associations were statistically significant.

Analysis of a population of Hobbit Sib x Avalon recombinant inbred lines (RILs) revealed year-on-year consistent statistically significant QTL for protein content on chromosomes 1A and 6B, and for texture on 5D (Ha). Single-year significant QTL were found for protein content on chromosomes 6A and 7A.

Analysis of neo-RILs from the cross Hope x Pastiche (both hard-grained) revealed year-on-year consistent associations between markers on chromosome 1B and protein content and markers on 6B and grain texture.

Analysis of the International Triticeae Mapping Initiative (ITMI) population for grain size and shape revealed a year-on-year consistent statistically significant QTL related to the ratio seed length / seed width on chromosome 2D.

Finally, a survey of hardness-conferring polymorphisms in puroindoline loci pina and pinb was conducted on a suite of commonly grown UK varieties. The allele pinb-D1b (Gly46 to Ser46) was by far the most common hardness-conferring allele detected in the hard wheats.