Elevated temperature modulates rice pollen structure: a study from foothill of Himalayan agro-ecosystem in India

Rice cultivation is practiced in various agro-climatic zones ranging from tropical to temperate. Anthesis is a critical stage for deciding productivity which is controlled by numerous biotic and abiotic stresses. Elevated temperature is one of the key abiotic stresses that adversely modulate the pollen formation and structure, i.e., infertility, results in productivity decline. The present study was conducted to investigate the effects of elevated temperature on morphological changes in pollen grains of rice grown in temperature gradient tunnel (TGT) constructed in filed condition. The ambient and TGT temperature varied from 31.84 °C_(max) to 20.56 °C_(min) and 41.91 °C_(max) to 22.37 °C_(min), respectively, during study period. The scanning electron and light microscopic study showed extreme morphological abnormalities viz. shape and size in pollen grains of rice exposed to elevated temperature as compared to ambient. These abnormalities induced by elevated temperature may drastically decline grain filling potential which ultimately reduces grain yield in future climate change. This study will enlighten rice researchers for further screening of rice genotypes thermotolerant to foothills of Himalayan agro-ecosystem.