PREVELANCE OF HIGHER GLUTENIN VARIATION IN SYNTHETIC WHEAT GERMPLASM

Genetic improvement in bread wheat (Triticum aestivum L., AABBDD, 2n=6x=42) for various economically important characters has remained a challenge for breeders. The present study investigated diversity of the high molecular weight (HMW) as well as low molecular weight (LMW) glutenin subunits in 84 wheat genotypes including Pakistani land races, cultivars and Aegilops tauschii derived primary synthetic hexaploid wheats (SHWs). For HMW-GS, 15 x-type and 9 y-type subunits were observed in all three groups. Nei’s diversity index was highest for Glu-D^t1 locus in synthetics hexaploid wheats and revealed that the D genome from Ae. tauschii carried maximum diversity for HMW-GS. Of the 33 different combinations, the highest combinations observed in SHWs were ‘null, 6+8, 2.1+10.5’ followed by ‘null, 6+8, 1.5+10’ and ‘2*, 6+8, 2+12’, while, the Pakistani cultivars and land races harbored ‘null, 20, 12+2’ and ‘1, 7+8, 2+12’ alleles. For LMW-GS, six alleles were found at Glu-A3 locus and nine were found at Glu-B3 locus. Predominant alleles were Glu-A3c, Glu-A3d and Glu-A3b, which were observed in 41 (50.61%), 19 (23.45%) and 12 (14.81%) genotypes, respectively. At Glu-B3 locus, at the most prevalent alleles were Glu-B3h (18.51%), and Glu-B3i (17. 28%). High number of HMW-GS (Glu-D^t1 locus) and LMW-GS combinations reported here highlights the potential use of SHWs for transferring allelic variation from this synthetic stock to bread wheat for broadening genetic base of quality traits. Furthermore, Ae. tauschii derived primary SHWs also encoded both x and y-type alleles and offers possibility of these SHWs for the introduction of novel glutenin variability into elite bread wheat cultivars for different end use products.