UNIQUE SSR MARKERS FOR DROUGHT TOLERANCE IN NEWLY-DEVELOPED BREAD WHEAT MUTANTS

AL-NAGGAR A.M.M.¹, SOBIEH S.E.S.², ATTA M.M.M.³, AL-AZAB KH.F.^4
1Department of Agronomy, Faculty of Agriculture, Cairo University, Giza, Egypt.
²Plant Reseasrch Department, Nuclear Research Center, Atomic Energy Authority, Inshas, Egypt.
³Department of Agronomy, Faculty of Agriculture, Cairo University, Giza, Egypt.
⁴Plant Reseasrch Department, Nuclear Research Center, Atomic Energy Authority, Inshas, Egypt.

Received : 07-11-2013     Accepted : 09-12-2013     Published : 30-12-2013
Volume : 2     Issue : 1       Pages : 15 - 25
World Res J Agron 2.1 (2013):15-25

Drought tolerance is the ability of a variety to remain relatively more productive than others under limited water conditions. Irradiation of seeds of 7 bread wheat genotypes with gamma rays was used in this study to create genetic variability amenable for efficient selection of new putative drought tolerant mutants. The objectives were to evaluate morphological traits of the mutants under water stress (WS) and well watering (WW) conditions and to characterize the drought tolerant mutants and their parents on the DNA level. A total of 57 putative induced mutants were selected from M₂ populations, 23 of them were selected under WS and 34 under WW. Out of them, seven M₃ families (SF1 through SF7) outyielded significantly their parents by at least 15% under WS. The most superior M3 family was SF3 (56.34 and 65.62% superiority over its parent Giza-168 under WW and WS, respectively). Fifteen SSR primers were used for RCR amplification of the genomic DNA of the best 7 M₃ families (mutants) and their 4 parents. The genetic similarity (Gs) ranged from 33 to 88%. The mutants SF3 and SF4 exhibited very low Gs (42 and 40%, respectively), with their common parent (Giza-168), indicating the efficiency of gamma rays in creating new genetic variability. The total number of amplicons detected by SSR was 45, while the number of polymorphic amplicons was 43, with an average polymorphism of 86.67%. The SSR analysis identified 11 genotype specific unique markers for the drought tolerance mutants and parents (5 positive and 6 negative unique markers). Thus, these bands can be verified as markers associated with drought tolerance in bread wheat and could help in breeding programs aiming at improving wheat productivity under drought conditions.