Genotype-Environment Interactions of Selected Rice Lines in Direct Water-Seeded Culture

Abstract

Five rice genotypes including 4 breeding lines (lines 36 and 42 from the cross of Aoinokaze//Lemont/Hinohikari and 53 and 76 from Yumehikari//Lemont/Hinohikari) and a reference cultivar, Hinohikari, were grown under various environmental conditions (year, location, plant density and nitrogen level) to determine the genotype-environment interactions for yield, yield components and yield adaptability in water direct-seeded culture. No genotype-year interactions were found in yield or yield components, i.e., the ranking of the genotypes did not change across the years. The interactions of genotype with plant density and nitrogen level were significant only in the percentage of filled grains, indicating that the ranking of rice genotypes for yield traits except the percentage of filled grains remained constant across plant densities and nitrogen levels. There were significant differences in the ranking in grain yield of genotypes between the plants cultivated in Fukuoka and Chikushino. However, line 42 was ranked the highest at both locations. The adaptability to environmental conditions evaluated by a regression method varied with the genotype and line 42 which showed high average yield and higher yield in high-yielding conditions was selected to be suitable for direct-seeded culture.