Technological properties of grain and flour in bread wheat (Triticum aestivum L.) genotypes carrying two loci that determine the endosperm structure

Background.The end-use of the bread wheat grain depends on the endosperm properties determined by the alleles of the Pinaand Pinbgenes at the Halocus on chromosome 5D. The mealy (soft) endosperm is generated by the biosynthesis of puroindolines – complete proteins encoded by these genes. When milled, such grain breaks down into small starch granules covered with proteins. Mutations that disrupt the synthesis or structure of puroindolines determine the hardness and vitreousness of the grain. Earlier, we discovered a new locus for grain softness, Ha-Sp, introgressed from the diploid species Aegilops speltoidesTausch, which also determines the formation of the soft endosperm structure. By combining two active loci in one genotype, we produced a supersoft grain line (SSL). The aim of the present work was to verify the interaction of the two loci Haand HaSpin other wheat genotypes and evaluate the technological properties of grain and flour in comparison with the existing SSL line.Materials and methods.The F3–F8 hybrids from crosses of the soft-grain spring cultivars ‘Golubka’ and ‘Lutescens 62’, carriers of the Halocus, with the introgressive line 84/98w, carrier of the Ha-Splocus, were used in the work. Grain from three field seasons was studied according to milling parameters and physical properties of flour and dough.Results.At the early stages of selection (F3:4), the families with milling parameters typical of bread wheat were identified, as well as supersoft-grain families with a small flour particle size (9–10 μm) and low endosperm vitreousness (29–49%). Targeted selection made it possible to obtain lines similar to the SSL line in terms of milling performance and flour strength.Conclusion.For the first time, a set of supersoft-grain lines with special properties of grain and flour was obtained on the genetic basis of three spring cultivars. They may be in demand for a wide range of end-uses, including both food and nonfood production purposes.

Sequence Diversity and Identification of Novel Puroindoline and Grain Softness Protein Alleles in Elymus, Agropyron and Related Species

The puroindoline proteins, PINA and PINB, which are encoded by the Pina and Pinb genes located at the Ha locus on chromosome 5D of bread wheat, are considered to be the most important determinants of grain hardness. However, the recent identification of Pinb-2 genes on group 7 chromosomes has stressed the importance of considering the effects of related genes and proteins. Several species related to wheat (two diploid Agropyron spp., four tetraploid Elymus spp. and five hexaploid Elymus and Agropyron spp.) were therefore analyzed to identify novel variation in Pina, Pinb and Pinb-2 genes which could be exploited for the improvement of cultivated wheat. A novel sequence for the Pina gene was detected in Elymus burchan-buddae, Elymus dahuricus subsp. excelsus and Elymus nutans and novel PINB sequences in Elymus burchan-buddae, Elymus dahuricus subsp. excelsus, and Elymus nutans. A novel PINB-2 variant was also detected in Agropyron repens and Elymus repens. The encoded proteins detected all showed changes in the tryptophan-rich domain as well as changes in and/or deletions of basic and hydrophobic residues. In addition, two new AGP sequences were identified in Elymus nutans and Elymus wawawaiensis. The data presented therefore highlight the sequence diversity in this important gene family and the potential to exploit this diversity to modify grain texture and end-use quality in wheat.