The development of a new bread wheat genotype carrying two loci for endosperm softness

The technological purpose of grain and flour wheat is largely determined by the grains endosperm structure. Its variability among wheat varieties depends mainly on the multiple allelism for a single Ha locus on chromosome 5D leading to a continuous variation of the trait. The grain endosperm can vary from hard and vitreous suitable for yeast baking to soft and floury favorable for confectionery and technical purposes. Furthermore, these traits, especially vitreousness, are strongly influenced by the growth conditions. Earlier, the Ha-Sp locus was introgessed into chromosome 5A of the bread wheat line 84/98w from Aegilops speltoides Tausch., which reduces endosperm hardness and vitreousness, like the dominant allele of the Ha locus. This paper is the first to describe the obtaining and testing of the supersoft lines combining in their genotype the homoeoallelic loci Ha-Sp of the line 84/98w and Ha of the soft grain cultivar Chinese Spring. The lines were isolated from 6–8 generations of self-pollinated F2 hybrids. They consistently exhibit a greater grain softness than the parental forms under both greenhouse and field conditions. These lines can be used in the breeding of wheat cultivars, the flour of which will not require chemical baking powder in the confectionery industry. It is also possible to use them for technical purposes for the production of bioethanol. In addition, these lines may serve as a genetic model for the study of the functional activity of homoeoallelic genes in the complex polyploid genomes of plants