Quality and endosperm storage protein variation in Argentinean bread wheat. I. Allelic diversity and discrimination between cultivars

LERNER, SE; KOLMAN, MA; ROGERS, WJ

JOURNAL OF CEREAL SCIENCE (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2009 vol. 49 p. 337 - 345

0733-5210

Abstract Genetic variability for the high molecular weight and low molecular weight glutenin subunits (HMW-GS and LMW-GS, respectively), plus the Chinese Spring-Cheyenne gliadin difference CSS-CNN, was analysed in a collection of Argentinean bread wheat cultivars. For the HMW-GS, three, five and two alleles were observed at the Glu-A1, Glu-B1 and Glu-D1 loci, respectively, in fourteen allelic combinations. Over 90% of these combinations were considered to be associated with good quality, based upon the Glu-1 score of Payne. For the LMW-GS, eight, seven and four alleles were observed at the Glu-A3, Glu-B3 and Glu-D3 loci, respectively, in fifty-one allelic combinations. Regarding quality, the alleles carried by Glu-D3 were mainly those previously shown to be associated with good quality, whereas this was not the case for the remaining two loci, which included at high frequency some alleles previously associated with poor quality, including the Glu-B3j allele carried by the translocation 1BL.1RS. The CSS gliadin variant, associated with poor quality, was also present at high frequency. Relatively few cultivars carried combinations for all the loci studied that would be expected to be associated with high quality. Mean genetic variation indices (H) for the six glutenin loci was 0.564, similar to values observed in other collections. The values for the Glu-A3 loci was higher than those for the Glu-1 loci, particularly for Glu-A3 and Glu-B3, comparable to mean values observed for the loci routinely used for varietal discrimination, for example the gliadin loci. The polymorphism information content (PIC) of these loci was also high (approximately 0.75) and comparable to values obtained for wheat by microsatellite analysis. Application of unweighted pair-group method using arithmetic averages (UPGMA) of the six loci plus the CSS-CNN difference showed that the 119 cultivars fell into 89 distinct combinations, the majority of which consisted of one cultivar, but with others containing a few (up to seven) cultivars. Hence, although the discriminating power of these storage protein variants was high, they would have to combined with other methods of analysis in order to discriminate all cultivars. Additional sub-grouping of the cultivars was also observed. The reasonably high genetic variability present in these cultivars as a whole and in each set originating from different breeding companies, implies that there remains scope for varietal quality improvement within this germplasm pool.