Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 3, 2005
Publication Date: January 30, 2006
Citation: Pedersen, J.F., Graybosch, R.A., Bean, S., Park, S.H., Tilley, M. 2006. Multiple waxy alleles in sorghum and their relation to granule-bound starch synthase and amylopectin physico-chemical properties. Meeting Abstract. Proc. 5th Australian Sorghum Conference. Technical Abstract: Grain of eight waxy (endosperm contains <2% amylose) sorghum lines, BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369, three wild-type checks, BWheatland, RTx430, BN122, and F2 families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase (GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. Two distinctly different naturally occurring waxy alleles were identified: one with no GBSS (wxa) and one with apparently inactive GBSS present (wxb). The two alleles are located in close proximity on the waxy locus, the wxb allele is dominant to the wxa allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content. Following discovery of the wxa and wxb alleles, the accessions identified as waxy in the U.S. photoperiod insensitive sorghum collection were screened for presence of amylose and GBSS, and physico-chemical properties of the amylopectin from these accessions were evaluated using a differential scanning calorimeter. Both wxa and wxb genotypes were identified in the collection. Amylopectin from waxy accessions generally had higher onset and peak melting temperatures than amylopectin from wild type accessions.