Effects of pre-anthesis moisture stress on floret sterility in some semi-dwarf and conventional height spring wheat cultivars

This study was conducted to investigate the response of some semi-dwarf Canada Prairie Spring wheat (Triticum aestivum) and conventional height (tall) cultivars of Canada Western Red Spring wheat to moisture stress at the booting stage. The effect on the frequency of sterile florets was determined in the two height groups. Drought tolerance was investigated using the electrolyte leakage test. The association of floret sterility with pollen viability under moisture stress conditions was also investigated. When fully watered, several of the semidwarf cultivars had a lower frequency of sterile florets compared with the tall cultivars. Moisture stress increased the frequency of sterile florets in both semi-dwarf and tall wheat cultivars. As moisture stress increased, the resulting sterility was significantly higher in semidwarf cultivars, relative to the tall cultivars (P less than or equal to 0.01). Comparisons between floret sterility and desiccation injury (estimated by electrolyte leakage tests) suggest that a high degree of floret sterility was not associated with lower levels of desiccation tolerance. Cultivar differences in pollen fertility and for electrolyte leakage in response to moisture stress were evident, but were distributed independently of height class.