Phenotypic Diversity and Associations of Some Potentially Drought‐responsive Characters in Durum Wheat

Abstract

Genetic improvement of crop plants for drought resistance is hindered by lack of information on variability and associations of drought‐response characters in breeding materials. We evaluated 3430 accessions in a world collection of durum wheat (Triticum turgidum L. var. durum) for 19 characters under severe moisture‐limiting field conditions at Swift Current, SK, Canada in 1984. Phenotypic diversity (H) and multicharacter associations were investigated in germplasm from nine durum wheat growing regions. The Middle East was one of the regions with a high level of diversity (H = 1.132). The rate of excised‐leaf water loss (RWL) was used as a possible indicator of drought resistance. Glaucousness, plant height, chlorotic leaf spots, days to flowering, and days to maturity were significantly associated with RWL in six to seven regions. The discrete multivariate log‐linear analysis involving these six characters revealed the first order (two‐character) and some second‐order (three‐character) associations. These five characters were chosen along with RWL as drought‐response characters that may be useful for establishing selection criteria for drought resistance. These results have important implications for developing durum wheat ideo‐types for high and stable production in drought‐prone environments.