Evaluation of Genotype * Environment Interaction in Rice by Statistical Model

Abstract

Regional Adaptability Test (RAT) was conducted to select promising breeding lines of rice for cultivation in specific regions. Analysis of genotype (G) and genotype by environment (G ´ E) interaction observed in RAT was carried out to test their adaptability for the distribution of elite breeding lines / varieties to various locations. Paddy rice yield data of RAT for ordinary transplanting in central plain areas from 1997 - 1999 were studied. Data showed that genotype variability (49%) was the highest and environmental variability (30%) was slightly higher than that of G ´ E interaction (21%) in rice paddy yield. The major determinants of productivity, among geological and meteorological factors, were sunshine hours, precipitation in mid September, and mean cloud amount. IPCA (Interaction Principal Component Analysis) 1 was correlated positively and significantly with precipitation but correlated negatively but significantly with sunshine hours and mean cloud amount in early July. However, this study failed to establish significant correlation between IPCA2 and environmental variables measured at each of the sites. This low level of IPCA2 correlation further suggests that other dimensions of the environment should be explored and examined. Three elite lines, Suweon 437, Suweon 433 and Suweon 442 were adaptable to Suwon and Yeoju, but Suweon 438 was found to be suitable for Hwaseong, Yeoncheon and Chuncheon. Hwaseonbyeo, Ilpumbyeo and Suweon 434 were adaptable in Suwon and Cheongju. The analysis further implied that Suweon 434 was adaptable to central plain areas. The statistical parameters from the regression model were compared with IPCAs from the AMMI (Additive Main effects and Multiplicative Interaction) model and were useful for understanding varietal adaptability.