Identification and Characterization of Mutant Lines for Resistance Towards Moisture Stress in Wheat (T. Aestivum L.)

Abstract

Wheat (Triticum aestivum L.) is family member of Poaceae and agronomically important family of plant kingdom. Aim of current study was to develop drought tolerant lines via chemical mutagens i.e. EMS and SA. Mutation breeding is a long-known that evolve new varieties with improved economic traits in a relatively short time span. EMS has the potential of altering loci or a candidate gene of specific interest without inducing any large deletions. SA generates chromosomal abnormalities at a relatively low rate. Two wheat genotype HD-3226 and HI-1620 was selected for mutagenesis. Screening through PEG is very effective method for studying water stress‘s effect on the seed germination and seedling growth characters. At seedling stage, EMS showed not much effect on germination of seeds in both varieties but in case of sodium azide, germination was delayed 4-6 days in both varieties of wheat after screening through 15% PEG. In M2 generation, plant height, tiller number, grain yield, leaf length and width significantly increased under water stress condition. Total twenty four mutants were selected on morphological parameters from M2 generation. In M3 gen. mutant- EMS-1% HD-3226 15% PEG, P-19 (57.72g) showed highest 1000 grain weight (g) while SA- 0.08% HI-1620 15% PEG, P-1 (59.12g) showed highest 1000 grain weight as comparison to wild type. ISSR markers were used for confirmation of variation in selected mutant plant of both genotype and UBC-810, UB- 814, UBC-815, UBC-840, UBC-845, UBC-848, UBC-852, UBC-853, UBC-855 and UBC-881 determined high rate of variation in mutant plants. The PIC values varies from 0.21 (UBC-853) to 0.81 (UBC-881) with average of 0.47 (EMS) and 0.39 (SA) while 0.00 (UBC-823) to 0.89 (UBC-848) with average of 0.35 (EMS) and 0.42 (SA) in HD-3226 genotype and HI-1620 genotype, respectively. Transcription factors (TFs) plays important role in gene regulation under water stress conditions. TaAREB3 is a new member of AREB transcription factor family it‘s isolated from wheat. DREBs are important plant transcription factors (TFs) that regulate expression of many stress-inducible genes. TaDREB2A gene was up-regulated in all four mutants of wheat under water stress condition as compared to control-WT while TaAREB3 gene showed similar expression in both control-WT and water stressed four mutants of wheat thus results indicate that TaDREB2A gene is responsible for moisture stress tolerance in selected mutant plants. The current study may be helpful for development of high yielding wheat genotypes.