DSSAT model simulates soybean ideotype to cope with projected changes in future climate of north interior Karnataka, India

Abstract

Among oil seed crops soybean is an important crop of India grown during kharif season. Grain yield of soybean under projected climate of 2020-2050 in rainfed conditions may decline due to increase in temperature and change in rainfall pattern. Hence, new type of cultivars may be required to suit to projected climate of coming decades and still continue to yield more. Crop simulation models have potential usage to evaluate genetic improvement of current cultivars and propose plant ideotypes for future projected climate. This study was carried out to come up with an ideotype for soybean variety JS-335 and to suggest breeders in their quest to identify potential traits for projected climate. Already calibrated select set of genetic coefficients (GC) which govern the main plant functions of variety JS-335 were modified in different combinations and were run under projected climate (2020-2050) in rainfed conditions to simulate yield output. The simulated yield with a combination of changed GCs surpassing the yield levels of current climate (1988-2018) under projected climate was identified. The study showed increasing thermal requirement (GC) of crop i) between plant emergence and flower appearance (EM-FL), ii) from first seed to physiological maturity (SDPM) and iii) the maximum ratio of seed to pod at maturity by 5, 10 and 15% simulated the best yields under projected climate on black clay soils resulting in an increment of 20 to 57%, and on red loamy soils an increment of 0.3 to 22%, respectively, compared to the yield under projected climate (2020-2050) in rainfed conditions on respective soils.