Agronomic and Yield Performances of Three Rice Cultivars (Oryza sativa L.) under Water Regimes in Dry Season

Abstract

Rice (Oryza sativa. L) is widely cultivated in Cambodia, but it consumes considerably more water than any other crops. In the context of water scarcity due to global climate change, rice cultivation in Cambodia has been worsened by the effect of drought. Development of a cultivation technique to minimize yield loss under drought stress or/and limited water resource in rice production is of great strategic value. Therefore, the present study aims to investigate growth and yield performances of three rice genotypes, namely CAR 14, CAR 15 and CAR 16 under different water regimes including drought (at flowering stage), alternative wet and dry (AWD), and flooded conditions. The experiment was conducted from January to October 2019, at the Tonle Bati Agricultural Development Center, located in Bati District, Takeo Province, Cambodia. The soil is clay loam and is classified as Toul Samrong (Soil Classification for Rice Production in Cambodia). Two-way ANOVA was utilized to determine interaction between the genotypes and the water regimes. As a result, the genotype-water regime interaction was detected for grain yield. Water regimes affected grain filling percentage and yield, whereas rice genotypes affected plant height, 50% flowering days, 100% flowering days, number of unfertile grains, grain yield, and 1000 grain weight. Nevertheless, plant density, panicle length, and straw biomass were not affected by either of the factors. In any water regimes, CAR16 grew the tallest at 94.4 cm and blossomed 2 to 4 days later than any other cultivars. In contrast, CAR 15 had the highest yield, observed in permanent flooding and in AWD. Although 27% of irrigation water was saved in AWD, permanent flooding produced more yield. In short, drought conditions affected total yield. Despite that, Car 15 was observed to be more suitable for any water regimes.