TITLE:
Physiological and Biochemical Basis of Water-Deficit Stress Tolerance in Pearl Millet Hybrid and Parents
AUTHORS:
T. Vijayalakshmi, Y. Varalaxmi, S. Jainender, S. K. Yadav, M. Vanaja, N. Jyothilakshmi, M. Maheswari
KEYWORDS:
Pearl Millet; Water Relations; Osmotic Adjustment; Membrane Stability Index; AntioxidativeEnzymes; Seed Yield
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.3 No.12,
December
26,
2012
ABSTRACT: The present investigation was aimed to understand the physiological and biochemical basis of water-deficit stress tolerance in pearl millet [Pennisetum glaucum (L.) R. Br.] hybrid ICMH 356 and its parents ICMR 356 (♂) and ICMB 88004 (♀) in response to and recovery from drought stress and also to comprehend crop adaptation under dryland conditions. A field experiment was conducted in a split plot design with moisture levels as the main plot and genotypes as the sub plots. A comparative analysis of hybrid and parents under well-watered and water-deficit stress conditions revealed that the hybrid was superior over the parents in terms of leaf water relations, excised leaf water retention capacity, accumulation of compatible solutes, photosynthesis, membrane stability index and antioxidative enzyme viz., superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) activities. ANOVA for these parameters was also found to be significant for genotypes, treatments and their interactions at 0.01% level. Maintenance of superiority in terms of these physiological and biochemical parameters coupled with better recovery ability upon stress relief are crucial physiological mechanisms contributing to water deficit stress tolerance in pearl millet. Simple correlation coefficient analysis revealed significant positive association of yield at 0.01% level with relative water content, leaf water potential, stomatal conductance, photosynthesis, proline, total soluble sugars, free amino acids, membrane stability index, leaf area index and total biomass, while a significant negative association with solute potential and malondialdehyde content, under water-deficit stress clearly indicated that such relationships can be positively attributed to drought tolerance.