Tolerance of lowland rice (Oryza sativa) genotypes to heat stress at anthesis

Abstract

Global warming is occurring all over the world and climate changes are likely to affect agriculture by raising the frequency of weather events with very high and very low temperatures, which will increase the risks for food production. This study aimed to evaluate the effect of heat stress at anthesis on the agronomic performance of modern Brazilian lowland rice genotypes. The varieties SCS124 Sardo, SCS122 Miura, SCS121 CL, SCS116 Satoru, SCSBRS Tio Taka, Epagri 109 and the inbreeds SC 491 ME, SC 676, SC 792, SC 806, SC 817, SC 849 were tested. At anthesis, plants which received heat stress treatment were transferred to a growth chamber for four days at temperatures of 38ºC (day) and 30ºC (night). After that, they were returned to a greenhouse, remaining there until harvest, under temperatures of about 25ºC. Spikelet sterility ranged from 4.0 to 84.1%. Yield varied from 10.2 to 101.2g pl-1. Heat stress increased spikelet sterility and decreased grain production. The inbreeds SC 817 and SC 806 showed the lowest percentage of spikelet sterility and the highest yield under thermic stress and are thus promising genotypes to generate tolerant cultivars to high temperatures at anthesis.

Keywords

• Oryza sativa
• estresse por calor
• esterilidade
• produtividade