Submitted to: Starch/Starke
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/26/2013
Publication Date: 6/18/2013
Publication URL: l;lk
Citation: Asante, M.D., Offei, S.K., Gracen, V., Adu-Dapaah, H., Danquah, E.Y., McClung, A.M., Bryant, R.J. 2013. Starch physicochemical properties of rice accessions and their association with molecular markers. Starch/Starke. 65:1-7. Interpretive Summary: Rice is an important cereal grain that feeds half of the world’s population. It is also being rapidly adopted as a staple food in Africa. Most of this increasing demand is being filled by imports because of current low production levels in Africa and poor grain quality standards. Traits that impact rice grain cooking quality include apparent amylose content (AAC), gelatinization temperature (GT), and starch pasting viscosity (RVA). Previous research has identified genetic markers that are linked to these traits and can be used in breeding programs to improve rice grain quality. This study was conducted to determine if rice cultivars that are being grown in West Africa differ for grain quality traits and if genetic markers hold promise as a breeding tool for rice grain quality. A set of 65 diverse cultivars from West Africa and 23 USA commercial cultivars were evaluated for AAC, GT, and RVA traits along with the genetic markers that are linked to these traits. Wider diversity was found among the West African material than USA cultivars. This is likely due to the long history of selecting for cooking quality in USA rice breeding programs that has eliminated some undesirable quality traits. In addition, the correlation of the genetic markers with cooking quality traits was greater within USA cultivars that the West African material. However, even within the diverse West African cultivars, the genetic markers were related to cooking quality traits indicating that the markers could be used to enhance breeding efforts to improve rice cooking quality in breeding programs in Africa.
Technical Abstract: The grain quality of rice has recently attracted a lot of attention around the world, including Africa. Rice germplasm in African gene banks has not been adequately characterized for its cooking and eating qualities which are mainly controlled by starch physicochemical properties. The aim of this study was to characterize two groups of rice germplasm from Africa and the U.S. for starch properties including gelatinization temperature (GT), apparent amylose content (AAC), and paste viscosity (RVA), and to determine molecular marker associations with these traits. Wide diversity was found for all traits studied. Variation in these traits was significantly associated with molecular markers for the alk and waxy genes which encodes soluble SS II (SSIIa) and granule bound synthase (GBSS) enzymes, respectively. Based on four previously reported waxy SNP haplotypes, 93.1 and 75.9% of the variation in AAC was explained for the U.S. and African germplasm, respectively. The classification of the genotypes by their SNP haplotypes helped to clarify the relationship between AAC and peak viscosity. The characterization of individual lines using physicochemical properties and functional markers, and the determination of marker-trait associations will facilitate the breeding of rice for grain quality in Africa and elsewhere.