Effect of high temperature at reproductive stage on seed set and seed quality of rice

Abstract

The increasing in air temperature, due to global warming, has direct impact on rice production. High temperature reduces pollen viability and seed set. Therefore, the objective of this experiment was to study the effect of high temperature at reproductive stage on seed set and seed quality of rice. The pot experiment was arranged in split-plot in CRD with 2 replications. Ambient and high temperatures (40±5°C) were main plots and 14 rice varieties were sub-plots. All rice varieties were planted in pots and sit in the field outside the greenhouse. At the reproductive stage (R2), 10 pots from each variety were tested in greenhouse under high temperature until harvest (R9) and compared with ambient temperature (field) condition. The results showed that high temperature significantly decreased number of panicle/plant, panicle weight/plant, good seed weight/panicle, seed set, 100-seed weight and yield/plant. Under high temperature, N22, Chainat 1 and RD49 had highly significant seed set (>75%). RD29, RD31, RD41, RD47, RD55, RD61, RD63, SuphanBuri 60 and Phitsanulok 2 had moderately seed set (50-74 %), while, PathumThani 1, Sin Lek and RD15 gave low seed set (<50 %). In addition, high temperature also affected seed vigor as determined by AA but no effect on seed germination of all rice varieties but RD15 and Sin Lek. Suphan Buri 60, RD41 and RD29 showed higher than 80% vigor as determined by AA.