Variation in seed dormancy of tetraploid wheat

Abstract

In western Canada, durum wheat cultivars, (Triticum durum) have low to moderate levels of seed dormancy and are susceptible to pre-harvest sprouting. The first objective of this research was to evaluate the dormancy level of Canadian durum wheat cultivars and to identify tetraploid wheat accessions with elevated levels of seed dormancy. Level of seed dormancy and length of after-ripening of 17 Canadian durum wheat cultivars and a collection of 78 tetraploid wheat germplasm were evaluated. The plants were grown under field conditions in 1995 and 1996, harvested at maturity (Zadok's Growth Stage 92), dried at room temperature for one week, and assessed for level of seed dormancy over seven weeks of after-ripening. The results indicated that the durum cultivars Kyle, Mindum, Pelissier, and Wascana exhibited moderate levels of seed dormancy at maturity while the remaining cultivars were non-dormant. Likewise, a rapid loss of dormancy (within 2-3 weeks of after-ripening) was characteristic of all durum cultivars. Seventy-eight accessions of 'T. turgidum', 'T. turanicum', 'T. carthlicum', 'T. polonicum', and 'T. durum' from the USDA germplasm collection were evaluated for seed dormancy with the idea of identifying potential breeding materials. At ZGS 92, eighteen accessions were classified as dormant. Accession 93-282 was the only highly dormant genotype

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