In Vitro Selection of Mungbean Genotypes for Drought Tolerance by Polyethylene Glycol Induced Water Defi cit

Abstract

Drought stress is a major constraint affecting growth and yield of several economic crops including mungbean [Vigna radiata (L.) Wilczek]. In vitro selection for drought tolerance is an alternative method for early determination of drought tolerant plants. The objective of this study was to perform in vitro selection of mungbean genotypes under water stress induced by polyethylene glycol (PEG) 6000. Seeds of 18 genotypes were germinated in Murashige and Skoog (MS) liquid medium supplemented with different concentrations of PEG 6000 (0, 8, 12 and 16%). Germination percentage, promptness index, root length tolerance index, seed vigor index, seedling length tolerance index, seedling fresh weight tolerance index and seedling dry weight tolerance index were measured. The results showed reduced germination and growth in all genotypes with increasing PEG concentrations. Various genotypes responded differentially at 16% PEG. Interestingly, K-851, EG-MG-13, VI000411 A-G, and CES 44 showed a higher germination percentage, root length, seedling length and seed fresh weight than other genotypes, demonstrating their drought tolerance potential. However, their water stress responses need to be confi rmed under greenhouse and/or fi eld conditions before they can be used as parents in breeding programs to improve drought tolerance.