Effects of Temperature and Photoperiod on Spring Wheat Pollen Viability1

Abstract

Seven cultivars of spring wheat (Triticum aestivum L. em Thell.) including the cultivars ‘Chris,’ ‘Crim,’ their male‐sterile counter‐parts, the restorer ‘Dirk’ and the Fl′s of the male‐steriles ✕ Dirk were subjected to the nine combinations of 12‐, 14‐, and 16‐hour photoperiods and 24 C ‐ 7 C, 30‐13, .and 35‐18 day‐night temperature regimes. Pollen viability was based on stainable grains and seeds per spike were counted. The r value between pollen stainability and seed counts was 0.87.Temperature had the greatest effect on pollen viability iu the experiment. In general, high temperatures reduced pollen viability. Photoperiod had minor effects with longer periods slightly reducing viability. Chris and Crim had the highest viabilities. The pollen viability of Dirk tended to drop sharply with high temperatures. The Fl′s were intermediate. Male‐sterile Chris had consistently low pollen viability. Male‐sterile Crim had quite viable pollen at low temperatures and short to medium daylengths, but low viabilities at other environments. Genotype ✕ environment interactions occurred only at the 14‐hour photoperiod where viabilities of Chris, Crim, and male‐sterile Crim were not reduced at high temperatures.