Temperature Regime Impacts on Reproductive Performance in Various Chickpea (Cicer arietinum L.) Genotypes

Background: Early flowering stages with low temperatures (0 to 10oC) may also result in increased floral abortion, which lowers pod and seed set. Both the duration and rate of grain filling are sensitive to temperature changes and high temperatures may reduce productivity due to decreased flowering, pod formation and seed set, which could result in a loss of output. To mitigate the effects of high or low temperatures on chickpea productivity, it is crucial to investigate pollen traits, including pollen fertility, sterility, germination, tube length and diameter. Methods: The field experiments were conducted at Main Agricultural Research Station (MARS), University of Agricultural Sciences (UAS), Dharwad during rabi 2018-19 and 2019-20 using six chickpea genotypes with three replications. Sowing dates i.e., Early sown (40th Standard Meteorological Week i.e., 5th October), normal sown (45th Standard Meteorological Week i.e., 5th November) and late sown (49th Standard Meteorological Week i.e., 5th December) of rabi season during 2018-19 and 2019-20 were manipulated in order to create the effects of high temperature. Result: Early-sown chickpea genotypes (planted in October) experienced low-temperature stress, while late-sown genotypes (planted in December) were subjected to high-temperature stress. The late sowing period led to poor performance due to high-temperature exposure, negatively impacting flowering, pod formation and seed set, ultimately lowering the productivity of the chickpea crops. Among the genotypes, positive correlation was seen between maximum temperature and pollen tube length and sterile pollen diameter during 2018-19 (0.770**, 0.545*) and 2019-20 (0.548*, 0.542*) and the average of two years (0.543**, 0.633**), respectively in JAKI 9218 genotype. This relationship was consistent across both years of the study (2018-19 and 2019-20), indicating that increased temperatures may influence pollen fertility and sterility, thereby affecting chickpea productivity.