Evaluation of chickpea (Cicer arietinum L.) genotypes for heat tolerance: a physiological assessment

A field experiment was carried out in factorial randomized block design to evaluate 56 chickpea (Cicer arietinum L.) genotypes for high temperature tolerance. High temperature was imposed by delaying sowing dates i.e. normal (9th November) and late sowing (19th December). 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 °C). Chickpea genotypes were assessed based on various physiological tests. A significant genotypic variability was recorded in relative water content, membrane stability index, canopy temperature depression (CTD), photosynthetic pigments, photosynthetic rate (PN), canopy photosynthesis, growth, and yield based indices. In general, late sown high temperature stress condition significantly reduced all the physiological, growth and yield parameters except CTD. For each trait promising genotypes under late sown (high temperature) condition were identified. Furthermore, photosynthetic pigment profile under late sown high temperature condition at podding stage was analyzed using thin layer chromatography and that also revealed the genotypic variations. Tolerant genotypes in general maintained darker bands and also showed more number of photosynthetic pigments than relatively sensitive ones. In addition to this, total carotenoids content, under late sown condition at podding stage exhibited significant positive association with heat tolerance index (HTI), CTD, rate of photosynthesis and total chlorophyll content. That in turn indicated that higher level of total carotenoids played important role to maintain heat tolerance under late sown high temperature condition by protecting the photosynthetic machinery. In general, genotypes identified for high temperature tolerance based on HTI, heat susceptibility index (HSI) and heat yield stability index (HYSI), also had better physiological performance as evident from higher values of almost all physiological parameters recorded during the present study. Further, on the basis of all over performance, eight genotypes Pusa 1103, Pusa 1003, KWR 108, BGM 408, BG 240, PG 95333, JG 14, BG 1077 proved to be high temperature tolerant (HSI ≤ 0.9, HTI ≥ 0.59 and HYSI ≥ 50%). © 2017, Indian Society for Plant Physiology.