Screening Soybean Genotypes for High-Temperature Tolerance by Maximin-Minimax Method Based on Yield Potential and Loss

Abstract

Temperature rise between 2.6 and 4.8 °C will impact the productivity of soybean at the turn of the twenty-first century. To predict differences in soybean genotypes to high temperatures, twelve soybean genotypes were grown in greenhouses maintained at a mean temperature of 26, 29, 32, and 35 °C, respectively, with one set in natural conditions. The leaf area, total biomass, photosynthesis, Fv/Fm, pollen germination, and reproductive efficiency were significantly high under natural conditions, and a further increase in temperature to 26, 29, 32, and 35 °C resulted in a decline in these parameters. The average seed yield of 12 soybean genotypes was 13.2 g/plant under ambient temperature and there was mild reduction of 8% and 14% when genotypes were grown at 26 and 29 °C, respectively. Severe decline by 51% and 65% in yield was observed at 32 and 35 °C, respectively. The total stress response index in twelve genotypes ranged from −1068 (JS 95-60) to −333 (EC 538828). NRC7 and EC 538828 performed comparatively better than other genotypes. Screening for high-temperature tolerance in soybean is very constrained in breeding programs. This genetic variability among soybean genotypes to elevated temperature reveals that heat tolerance can be improved through plant breeding programs. Additionally, it emphasizes the significance of identifying efficient selection strategies in improving the productivity of soybean in future climate scenarios.

Keywords

• maximin-minimax
• photosynthesis
• reproductive efficiency
• soybean
• temperature
• yield