Analysis of genotype by environment interaction in irrigated lowland rice (Oryza sativa L.) varieties under diverse agroclimatic environments
2017
Makahiya, H.A.F. | Perdiguerra, K.N.C. | Marajas, I.R.M. | Edaño, Ma.L.S. | Hernandez, J.E. | Sta. Cruz, P.C.
Determining the factor involved in yield variability due to genotype by environment (G x E) can be helpful when looking for sites with contrasting environments for effective multi-environment trials. In rice multi-environment trials however, limited information is available on the agroclimatic factors that can describe the yield variation due to G x E. Field experiments were conducted for two cropping seasons each in selected major rice growing areas in the Philippines. Rice varieties tested were NSIC Rc222, PSB Rc18 and Mestiso 19. Agroclimatic parameters such as the cumulative daily rainfall, solar radiation, minimum and maximum temperatures, and indigenous nitrogen supply in each environment were determined. Grain yield and agronomic parameters were obtained. Environment accounted for the largest variability in grain yield of the three rice varieties. Environmental differences can greatly contribute to the varying yield performance of genotypes across cropping seasons and locations, as shown by the G x E effect being more than twice that of genotype effect. Among agroclimatic factors, only cumulative daily rainfall had significant positive correlation with IPCA1 environmental scores but not on environmental mean yield. Interaction between genotype and cumulative rainfall accounted for 54.6% of the total yield variation due to G x E. The differences in rainfall patterns among the environments contributed to a considerable proportion of yield variation due to G x E. The use of environmental variables to interpret the large variation due to G x E is important, such as identifying the traits that respond to rainfall variability. Aside from rainfall, the cumulative solar radiation during the reproductive and grain filling stages could have favourable contribution on good yield performance. It will be helpful in developing varieties that have stable productivity across environments with high rainfall variations.
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