Performance of elite upland rice lines at low temperatures

Abstract

The objective of this work was to evaluate the phenotypic performance of elite upland rice lines subjected to different temperature conditions during the booting stage (R₂). Eight elite lines from an upland rice breeding program were evaluated under six temperatures: 12, 17, 20, 25, 29, and 32ºC. The experiment was conducted in a greenhouse and climatic chambers with photoperiod control. The experimental design was completely randomized, with three replicates. Number of days to flowering, plant height, number of panicles, and spikelet sterility were measured. The upland rice lines do not tolerate the low temperatures of 12 and 17ºC, which result in a low performance in yield components and a grain sterility of 100%. The lowest rates of spikelet sterilization occur at the temperatures of 25 and 29ºC. Cultivar BRSMG Caçula is a promising candidate to integrate the crop succession system.