Registration of two extra-soft soft red winter wheat germplasms carrying the puroindoline genes on chromosome 5A

Kernel hardness is a primary determinant of the milling and end use quality of wheat (Triticum aestivum L.) and is largely genetically controlled by the Pin genes on chromosome 5D in common wheat. Wheat carrying the wild-type alleles of the Pin genes exhibits softer kernel texture, higher break flour yield, finer flour particle, and lower damaged starch content than wheat carrying one or two mutant alleles of the Pin genes. The USDA-ARS developed and released two extra-soft soft red winter (SRW) wheat germplasms, SWQL11-146-4 (Reg. no. GP-1100, PI 706439) and SWQL11-156-5 (Reg. no. GP-1101, PI 706440), by introgression of the Pin genes on chromosome 5A (Pin 5A genes) from a ‘Chinese Spring’ translocation line to SRW wheat cultivars. SWQL11-146-4 and SWQL11-156-5 were derived from the crosses of OH04-264-58*2//T5A^mS-5AS∙5AL R#45/OH04-264-58/3/GA 991371-6E13 and Milton/T5A^mS-5AS∙5AL R#45//3*USG 3555, respectively, and were grown in four different environments and analyzed for grain and milling characteristics and agronomic performance. Kernel hardness values averaged across environments were 0.7–1.4 in extra-soft wheat germplasms, 15.3–17.4 in their sibling lines without the Pin 5A genes (wild types), and 18.7-21.3 in recurrent parents. The break flour yields of SWQL11-146-4 and SWQL11-156-5 were significantly higher than those of the corresponding wild types and parents. SWQL11-146-4 had a higher test weight and flour yield than its wild types and parent. The introgression of the Pin 5A genes induced insignificant changes in kernel diameter and weight, grain protein content, and agronomic performance (heading date, plant height, and grain yield). These two extra-soft wheat germplasms would be valuable genetic resources for improving the milling and end use quality of soft wheat.