Effects of Rht dwarfing alleles on wheat seed vigour after controlled deterioration

Abstract

Reduced height (Rht) alleles, commonly known as the ‘Green Revolution’ genes, have facilitated wheat breeding programs and achieved globally a more than 10% wheat yield increase. However, studies in barley indicate that shorter plant habits are associated with reduced seed vigour and longevity. Therefore, wheat seeds of six near-isogenic lines (NIL) carrying the dwarfing alleles Rht-B1b, Rht-D1b, Rht-B1c, Rht-B1b+-D1b, Rht-B1c+-D1b and the wild-type allele Rht-B1a+-D1a, each in four background cultivars, were stressed by controlled deterioration. Seed vigour expressed as root and shoot lengths, time to 50% (T50) and time between 16 and 84% (T16-84) germination showed significant changes after treatment. However, after controlled deterioration only a combination of Rht alleles highly affected T16-84 and T50, which followed the general pattern Rht-B1c+-D1b followed by > Rht-B1c > Rht-B1b+-D1b > Rht-B1b > Rht D1b = Rht-B1a+-D1a (wild type). Interestingly, only under control conditions seed vigour correlated positively with thousand-kernel weight, which decreased with severity of Rht type. Further, the seed length was not affected by the different NIL. In conclusion, NIL carrying combinations of Rht alleles tend to influence seed vigour, which could influence seed longevity. Therefore, plant breeders but especially genebank managers should consider that the genetic background of genotypes may affect seed deterioration processes, which could be an economically important aspect in future.