Studies on morpho-phenological traits and heat unit accumulation in chickpea genotypes under different temperature regimes

Field experiment was carried out in factorial randomized block design to evaluate chickpea (Cicer arietinum L.) genotypes for high temperature tolerance. High temperature was imposed by delaying sowing dates i.e., normal sown (D1 temperature regimes at 41st SMW) and delayed sowing (D2 and D3 temperature regimes at 43rd and 46th SMW). Under late sown condition, high temperature was experienced by crop starting from flowering stage to crop maturity (during this period maximum temperature ranged from 25 to 40 oC ranged from 25 to 40 oC). Chickpea genotypes were evaluated for various morpho-phenological and heat unit’s accumulation under different dates of sowing. A significant genotypic variability was recorded in plant height, number of branches, phenological stages and thermal indices viz., growing degree days (GDD), phenol-thermal index (PTI) and heat use efficiency (HUE). In general, delayed sown condition significantly reduces all the morphological parameter and reduced phenological stages which varies the thermal indices. The genotypes performed better in D2 temperature regime with respect to morpho-phenological traits which showed higher plant height, number of primary branches and number of secondary branches which also took more number of days and accumulates optimum heat units for days to flowering, days to fifty per cent flowering, days to pod initiation and days to maturity and also showed decreasing trend in phenol-thermal index (PTI) with higher heat use efficiency (HUE) and yield was recorded in D2 temperature regime. Hence, by considering all these parameters that all chickpea genotypes sown during 43rd SMW showed better performance by delaying 15 days than the normal date of sowing and also the genotypes JG-14, J-11 and Anigeri-1 showed lessr yield reduction in delayed sown condition than Jaki-9218 and KAK-2.