The adaptation of four rice (Oryza sativa L.) varieties/lines at the vegetative stage in drought conditions

Abstract

This study was conducted to investigate the biochemical adaptation of four rice varieties/lines under to vegetative stage drought stress. Experiment units were arranged in a two-factor randomized complete block design: the first factor was four rice varieties/lines (CTUS4, Nang niu, IR64, LH01), and the other was irrigation conditions (irrigated, drought stress), with three replications. The IR64 was used as a drought-sensitive control. The results show that, there was a high accumulation of chlorophyll, total sugar, and proline in leaves of the four rice varieties/lines to adapt to the drought conditions. Chlorophyll a
content increased by 1.1-1.6 times, chlorophyll b content increased by 1.2-1.5 times, total chlorophyll content increased by 1.3-1.4 times, total sugar content increased by 1.2-3 times, and proline content increased by 2.2-9.5 times. The CTUS4 and LH01 had the lowest total sugar and proline accumulation. Total sugar and proline had a high genotypic coefficient of variation (GCV) and a high heritability (h2 ), which shows that the selection for such characters could be fairly easy due to a high additive
effect for drought tolerance.