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GLYCINEBETAINE ACCUMULATION AND ITS RELATION TO YIELD AND YIELD COMPONENTS IN COTTON GENOTYPES GROWN UNDER WATER DEFICIT CONDITION

M. KASHIF SHAHZAD SARWAR¹, IHSAN ULLAH¹, MEHBOOB-UR-RAHMAN¹, M.YASIN ASHRAF² AND YUSUF ZAFAR¹

Abstract: An experiment was conducted to investigate the genotypic variability and relationship between accumulation of glycinebetaine and productivity traits under field induced water stress at the flowering and boll maturation stage. Twenty cultivars/genotypes were evaluated for seed cotton yield (SCY), number of bolls per plant (BN), boll weight (BW) and glycinebetaine (GB) content under well watered (W₁) and water limited regimes (W₂) during the cropping season 2006. Glycinebetaine level in 20 genotypes / cultivars under water stress conditions ranged from 9 to 21 µmol g^-1 FW while in well watered conditions, this ranged from 0.5 to 1.5 µmol g^-1 FW. Genotypes BH-160, FH-87, MNH-552, CIM-1100, FH-901 and NIAB-Karishma had the higher concentration of GB during water stress as compared to other genotypes, whereas RH-510, NIBGE-160 and FH-1000 had relatively lower concentration of GB. Genotypes with low accumulation and better yielder under water stress may be attributed to their long root system and short life cycle of these genotypes. GB was positively and significantly correlated with seed cotton yield and boll number, while a positive and non-significant correlation was also recorded for GB with the boll weight (BW) under stress condition. Highly significant correlation was observed between BN and SCY. Significant differences in reduction of SCY, BN and BW were observed in W2. Genotypes with high GB level showed a significant increase in SCY, BN and BW under water-limited regime (W₂). Results indicated that selection for higher glycinebetaine has the potential to speed up breeding for drought tolerance in cotton.

¹Plant Genomics & Molecular Breeding Lab, National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, Pakistan
²Plant Stress Physiology Lab, Nuclear Institute for Agriculture & Biology (NIAB), P.O. Box 128, Jhang Road, Faisalabad, Pakistan.
Corresponding Author: M. Kashif Shahzad Sarwar; dhelvi_jat@yahoo.com