Adaptability of garlic (Allium sativllffl) genotypes to alkali stress

Abstract

A study was conducted during winter season of 1998-2000 to evaluate 17 diverse genotypes and land races ofgarlic

(Alltul1'l sativum L.) for their adaptability and growth performance under alkalinity stress (pH 9.22, 9.56 and 9.81) besides a non-stress control. Plant dry weight ofdifferent genotypes ranged fron1 137 mg ('Lucknow B') to 371 mg ('Local Red") at 30 days after sowing under the control conditions. An10ngst all the genotypes, ~Local Red' recorded a maximun1 concentration of8.2 n1g Na/g dry weight at pH 9.56, whereas 'HG l' the minin1un1 of4.3 n1g Nalg. In general, under alkali stress garlic yield declined by 430/0 at pH 9.22 and 71% at pH 9.56. Besides" 'Local Red' also recorded the nlininlunl percentage reduction in bulb weight at pH 9.22 (12%) and at pH 9.56 (320/0) compared with the control. Significant positive correlation (r=0.84) was recorded between seedling dry weight and final bulb yield, and bulb yield with potassiUln accunlulation in leaves (FO.83). Fifty per cent reduction (Cso) in bulb yield was noticed at pI-I 9.19, whereas threshold level (C\) was C0I11puted to be at pH 8.30. However for better perfonning 'Local Red' the threshold value was observed at pH 8.53 aild 50% reduction in bulb yield was at pH 9.65. Detailed ionic analysis of the 2 genotypes with maXill1Um ('Local Red') and n1ininlunl ('Lucknow B') bulb weights at pH 9.56 showed better partitioning of the accumulated toxic ions in 'Local Red' genotype wit~ higher accumulation in roots than 'Lucknow B'. Better performance of 'Local Red' was also associated with higher Inaintenance ofK in their plant parts under increasing alkali stress. Lower Na:K and Na:Ca ratios in consunlable part ofthe bulb in 'Local Red' were also recorded supporting its higher tolerance under stress than 'Lucknow B'.