*Corresponding author’s present address: Department of Basic Science, GBPUA&T, Hill Campus, Ranichauri, Tehri Garhwal-249 199, E-mail: panks_kr@yahoo.co.in Indian J. Plant Physiol. , Vol. 11, No. 2, (N.S.) pp. 166-171 (April-June, 2006) Indian J. Plant Physiol., Vol. 11, No. 2, (N.S.) pp. 166-171 (April-June, 2006) BIOCHEMICAL AND PHENOLOGICAL EVALUATION OF CHICKPEA GENOTYPES DIFFERING IN DROUGHT TOLERANCE PANKAJ KUMAR*, P.S. DESHMUKH, R.K. SAIRAM, S.R. KUSHWAHA AND TEJ PAL SINGH Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi-110 012 Received on 10 March, 2005, Revised on 9 June, 2006 SUMMARY Field experiment was conducted to study the mechanism of moisture stress tolerance during flowering and grain filling stages in chickpea genotypes, and its impact on seed yield. Eight chickpea genotypes (four tolerant and four susceptible) of different adaptations were taken for the study. Soil moisture extraction pattern showed that chickpea crop drew soil moisture from deeper root zone upto 90-cm depth. Greater accumulation of solutes like sugar, soluble proteins and proline content was observed under moisture stress condition at 105 DAS. However, at the later stage of crop growth (125 DAS) under rainfed condition, the soluble protein and soluble sugar contents decreased below the irrigated- control plants, while proline content was slightly higher than control plants. Under rainfed condition greater accumulation of solutes occurred at comparatively higher osmotic potential at 105 DAS than at 125 DAS, when plants showed much lower osmotic potential. Susceptible chickpea genotypes showed reduced grain filling duration (11-14 days) and greater reduction in seed yield as compared to tolerant genotypes. Thus, it can be concluded that chickpea genotypes have osmoregulation as mechanism of drought tolerance at lower osmotic potential. Key words: Chickpea, drought, osmotic potential, proline, seed yield, soluble proteins. INTRODUCTION India is one of the major pulses growing countries in the world, accounting for roughly one third of the total world area under pulses and one fourth of the total world production (Anonymous 1999). Among the pulses, chickpea (Cicer arietinum) is the most important crop representing about 27 per cent of the land area under pulse, which contributes 33 per cent of the total pulse production in India (Anonymous 2000). Chickpea is grown across a wide range of environments in India and other countries (Siddique et al. 2000) and cultivated as a rainfed crop on residual soil moisture (Saxena et al. 1990 and Leoport et al. 1999). The chickpea crop experiences moisture stress during flowering and grain filling stages under Northern Indian conditions. Osmotic adjustment is considered as an important physiological mechanism of drought adaptation in many plants (Subbarao et al. 2000) and particularly in chickpea cultivars at lower osmotic potential (Chopra et al. 1995, Leoport et al. 1998). Osmotic adjustment requires regulation of intracellular levels of several compounds, collectively known as osmolytes (Janardhan and Bhojraja 1999). Leoport et al. (1999) observed considerable genetic variation from 0 to –1.3 MPa in osmotic adjustment among chickpea genotypes. Besides causing the accumulation of specified compounds, water stress 166