Drought is the water deficit that impairs plants growth, development and yield compared with the normal water supply required for optimum growth. The drought which is an abiotic factor is one of the most common stresses that greatly hampered plants growth and development compared to other types of plant stresses. Plants tolerance to drought stress is a relevant issue that requires new improvement techniques like biotechnology to enhance stress-tolerant. The most common factors that influence plants tolerance to drought stress includes; the physiology of the plant, the extent of the plant stress, the growth stage, gene expression, the specie of the plant, etc.. Recent advances in plant biotechnology has seen remarkable progress in molecular markers selection processes and in developing transgenic plants with increased drought stress tolerant. These approaches have facilitated our understanding of underlying processes in plant responses to drought induced stress. Through plant genetic engineering and molecular marker techniques, drought stress induced genes have been identified and cloned. It therefore means that the applications of biotechnological and molecular approaches such as genomics, proteomics, and transcriptomic that can enhance a better understanding of plant water use efficiency and tolerance to improve yield under drought stress is very promising.
Citation: Chalachew Mesfin (2022) The Application of Molecular Plant Biotechnology for Improvement of Drought Tolerance, European Journal of Botany, Plant Sciences and Phytology, Vol.7, No.1, pp.28-61
Drought is increasingly becoming a common natural phenomenon that adversely affects maize productivity in Lesotho necessitating mitigation strategies. Irrigation may be a viable option but water is becoming scarce, hence choice of drought tolerant cultivars maybe the best alternative. The study was conducted in Lesotho with the aim of (1) verifying the differences among maize cultivars in response to induced water deficit stress, (2) evaluating maize cultivars against different concentration levels of Polyethylene glycol which induces drought stress in germinating seed and seedling growth and (3) identifying cultivars of maize tolerant to drought stress. Complete Randomized Design with three replications and 22 treatments were employed in the laboratory experiment. Twenty-two different accessions of maize were collected from Department of Agricultural Research in Maseru, Lesotho, were evaluated for their genetic potential to drought tolerance at seedling stage. Water stress was induced by non-ionic water soluble polymer polyethylene glycol (PEG) of molecular weight 6000 using the procedure which was described by Michel and Kaufiman (1973). After ten days, data were collected on plumule length, radicle length, coleoptile length, radicle fresh weight, plumule fresh weight, coleoptile fresh weight, radicle dry weight, plumule dry weight and coleoptile dry weight. Analysis of variance was performed using Genstat recovery Version 14 to establish the difference among treatments. The results showed significant differences (P<0.05 and P<0.01) among the accessions, PEG-6000 concentrations and their interactions for evaluated seedling traits suggesting a great amount of variability for drought tolerance in maize cultivars. It was further revealed that as concentration of PEG is increased, values of the parameters measured decreased. The maize cultivars which outperformed the others in terms of drought tolerance were CAP 9019, SNK 2778, DKC 78-27, PAN3MO1 and Natal.
Drought is increasingly becoming a serious challenge reducing common bean productivity in Lesotho. A study was conducted in Lesotho with the object of (1) verifying the differences among common bean cultivars in response to induced water deficit stress, (2) evaluating common bean cultivars against different concentration levels of Polyethylene glycol which induces drought stress in germinating seed and seedling growth and (3) identifying cultivars of common beans tolerant to drought stress and rank top performing accordingly. Complete Randomized Design with three replications and 28 treatments were employed in the laboratory experiment. Treatments were seeds of common bean cultivars obtained from Department of Agricultural Research in Maseru, Lesotho and four different concentrations of PEG-6000. Parameters measured were germination percentage, germination stress index, plumule length, radicle length, plumule fresh and dry weight and radicle fresh and dry weight. Significant differences (P<0.01) among cultivars of common beans in relation to induced procedure of determining drought tolerance as described by Michel and Kaufiman (1973) was followed. Data generated from the experiment were subjected to ANOVA using Genstat Version 14. Mean separation was done using LSD. The results revealed that gifferences exit among bean cultivars.Different concentrations of PEG created highly significant (P<0.01) different environments for common bean cultivars. Interactions of common beans and PEG concentration created highly significant different (P<0.01) environments in which seed germinated and seedlings grew. Kranskop and Small white haricots cultivars obtained highest values in five drought stress indices out of eight measured, followed by CAP 2000, Mkuzi, Nordak, RS7 and DBS 840 cultivars with highest values in four drought stress indices, lastly followed by PAN 148, PAN 9213 and DBS 310 in three drought stress indices.