Adaptability of High-Yielding Rice Cultivars in Relation to Biomass Productivity under Moderately Water Stressed Upland Conditions

Abstract

Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant's ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.

The performance of agronomic traits, genetic variability, and correlation studies for yield and its components in some red rice (Oryza sativa) promising lines

“…In the country where rice consumption has increased, the high-yielding cultivar with broad adaptation capabilities to diverse environments needs to be developed (Hyoda et al 2015;Bailey-Serres et al 2019;Takai et al 2019). According to Akter et al (2014), the development of improved varieties can increase the productivity of red rice 3995 through plant breeding programs.…”