Phenotypic Effects of the Flowering Gene Complex in Canadian Spring Wheat Germplasm

Abstract

Wheat (Triticum aestivum L.) has inherent genetic potential to synchronize its flowering and maturity to a broad growing period and is therefore one of the most widely adapted and grown food crops. Vernalization and photoperiod response genes are of primary importance to this adaptability. We screened 102 Canadian spring wheat cultivars and/or lines, developed between 1885 and 2008, from the Canada Western Red Spring (CWRS), Canada Prairie Spring Red (CPSR), and Canada Western Soft White Spring (CWSWS) classes and studied their phenotypic response both in the field and the greenhouse. Almost all the hard red cultivars possessed the Vrn‐A1a gene either alone or in combination with the dominant Vrn‐B1 while 74% of the higher yielding soft white lines possessed the Vrn‐B1 gene alone or in combination with other Vrn genes. The Vrn‐A1a alone or in combination with the Vrn‐B1 gene was the most potent gene conferring early maturity. Ppd‐D1a did not alter flowering and maturity in the hard red cultivars tested in the field but did in the greenhouse. Ppd‐D1a reduced days to flowering for soft white spring wheat but did not alter maturity. The photoperiod sensitive gene (Ppd‐D1b) is being replaced with the insensitive gene, Ppd‐D1a, in most modern Canadian germplasm, suggesting its adaptive advantages in the prairies. An overall analysis of the data for the hard red class revealed a declining trend of 0.04 d yr−1 in days to maturity in cultivars released from 1885 to 2008 and an increase of 8 kg ha−1 yr−1 in grain yield. The findings of this study may aid wheat breeders selecting parents with appropriate vernalization and photoperiod gene complexes.