Comparison of Methods of Pollen Selection for Heat Tolerance and Their Effect in Segregating Population of Maize (Zea mays)

Abstract

The reproductive stage in many crops including Maize (Zea mays L.) is most sensitive to heat stress. Due to limitations in sporophytic selection, an alternative pollen selection approach opens a way for breeders to develop heat stress resilient lines. In present study, the efficiency of different methods of pollen selection for heat stress tolerance was evaluated. The effect of selection in F1 generation in terms of the frequency of heat-tolerant plants in F2 generation was assessed. The heat susceptible line BTM4 was crossed to heat-tolerant BTM6, and the true F1 plants were identified using two SSR markers. Three different methods of pollen selection for heat tolerance, viz. incubating the freshly dehisced pollen grains of F1 plants at 36 °C for 3 h in growth chamber (GRC), dry bath (DB) before selfing and growing F1 plants in summer at ARS, Bheemarayanagudi (BGD). Thus, selected F2 from different treatments was produced. The control F2 was also produced without heat treatment of pollen grains. The control and selected F2 population were compared for heat tolerance by selfing the F2 plants with heat-stressed pollen grains. The selected F2 (GRC) showed superiority over other methods for seed yield traits and its component traits and also positive effect of pollen selection for heat tolerance.