Mapping of rice thermal properties and its relationship to the Alk and Waxy genes

Authors: McClung, Anna; Chen, Ming Hsuan; Bergman, Christine; Fjellstrom, Robert

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2003
Publication Date: 12/10/2003
Citation: McClung, A.M., Chen, M., Bergman, C.J., Fjellstrom, R.G. 2003. Mapping of rice thermal properties and its relationship to the alk and waxy genes. In: Proceedings of the Plant and Animal Genome Conference. p. 168.

Interpretive Summary:

Technical Abstract: Gelatinization temperature of rice flour is an important trait for determining cooking quality. The alkali spreading value (ASV) method is a simple technique for determining gelatinization temperature categories. ASV is believed to be controlled by either one or two genetic factors. This study was conducted to determine the inheritance of factors associated with ASV and to develop markers that are closely linked to this trait. We evaluated progeny from three genetic populations segregating for amylose content and/or ASV. Variation in ASV was mapped to regions containing the Alk and/or Waxy genes, encoding soluble starch synthase IIa and granule-bound starch synthase, respectively. In a genetic cross where both genes are segregating, our results indicated that ASV is primarily controlled by the Alk gene and secondarily controlled by the Waxy gene. In a cross where only Alk is segregating, Alk has a very large QTL effect on ASV. Whereas in a cross where only Waxy is segregating, the Waxy gene provides a large QTL effect on ASV and a small, but significant, QTL effect was associated with the locus encoding starch branching enzyme I. In addition to developing markers that can be used in narrow breeding crosses, we have also developed SNP markers for Alk and Waxy that are associated with changes in ASV across a wide array of international germplasm.