Yield stability of biofertilizer treatments to soybean in the rainy season based on the GGE biplot

Soybeans ( L.) play an essential role in meeting the nutritional needs of Indonesians. However, national soybean production cannot meet domestic needs. Increasing the planting frequency during the rainy season is an effort to increase the national soybean production. Planting soybeans in the rainy season will reduce the yield and growth of soybeans, so cultivation technology is needed to increase soybean yields in the rainy season, one of which is the use of biofertilizers and cultivars. This study aimed to analyze a suitable combination of cultivation and biofertilizer doses to increase soybean production during the rainy season. Selection of the right cultivar combination and biofertilizer dosage will increase yields. The research was conducted from 2021 to 2023 during the rainy season in Majalengka Regency, West Java Province, Indonesia. The cultivation technology that provides stable soybean yields was analyzed using a GGE biplot. The results of this research show that the appearance of soybean yields varies every year, and there is an interaction between the application of cultivation technology and the year of planting. Cultivation technologies that show a stable appearance are Anjasmoro variety + 20 kg h dose biofertilizer, Dega 1 variety + 0 kg h dose biofertilizer and Dega 1 variety + 10 kg h dose of biofertilizer. These results can be used as a reference for farmers planting soybeans during the rainy season.