Analysis of grain yield stability in rainfed lowland rice lines using Ammi biplots

Development of cultivars with high and stable performance across environments is one of the keys to a sustainable rice production. Thus, evaluation of genotypes for adaptability and stability has become an essential part of breeding programs. The current study was conducted to evaluate the grain yield stability of rainfed lowland rice lines and to identify genotypes with high and stable yield. Sixty rainfed lowland rice lines were planted during 2017 wet season in Cagayan, Laguna, Camarines Sur, and Iloilo, following an augmented row column design with two replications in each location. Grain yield differed significantly (P0.01) as affected by varying genotypes, environments, and genotype x environment (GxE) interaction. Highest mean grain yield across the four locations was observed in G60 (GSR IR2-DQ3-D1-S1) with 3.8 t/ha. Based on AMMI 1, genotypes G60, G56 (IR107891-B-B-954-3-1), G15(PR39288-B-4-2-2-1-3-1), G40 (GSR IR2-DQ41-L3-R1), G58 (GSR IR2-DQ25-S2-Y1), G9 (BRGYT 4), G46 (IR 106317-16-2-2-1), and G38 (GSR IR2-DQ30-L1-Y1) have the higher mean yield than the average yield across locations. In terms of growing environment, highest grain yield for each genotype was observed in Iloilo. From the AMMI 2 biplot, Camarines Sur and Cagayan had stronger interactive forces than Laguna and Iloilo. Genotypes G10 (PR39920-B-15-1-15-1), G11 (PR41561-B-8-Sal717-1-3), G15, G16 (PR40872-B-2-3-2-1-2-1), G32 (IR15L1504), G46, G56, and G60, are not sensitive to environmental interaction; while entries G21 (PR43482-13-1-1-3), G51 (PR42167-B-B-27-1-3-1), and G5 (Raeline 7) have high interaction with the environment. The most stable genotypes across environments are G22(IR15L1656), G30 (IR107891-B-B-1253-1-1), G37 (GSR IR2-DQ2-S1-S1), G56, and G58. Overall, G60 is considered as the best genotype among the rainfed rice lines evaluated due to its high yield, high adaptability, and non-sensitivity to environmental interactions.