RESEARCH ARTICLE Starch physicochemical properties of rice accessions and their association with molecular markers Maxwell Darko Asante 1,2 , Samuel Kwame Offei 1 , Vernon Gracen 1,3 , Hans Adu-Dapaah 2 , Eric Yirenkyi Danquah 1 , Rolfe Bryant 4 and Anna McClung 4 1 West African Centre for Crop Improvement, College of Agriculture and Consumer Sciences, University of Ghana, Legon, Ghana 2 Council for Scientific Industrial Research-Crops Research Institute, Kumasi, Ghana 3 Department of Plant breeding and Genetics, Cornell University, Ithaca, NY, USA 4 Dale Bumpers National Rice Research Center, Stuttgart, AR, USA 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. Received: March 1, 2013 Revised: March 25, 2013 Accepted: March 26, 2013 Keywords: alk gene / Cooking and eating quality / Rice / Starch properties / waxy gene : Additional supporting information may be found in the online version of this article at the publisher’s web-site. 1 Introduction Rice is the fastest growing food source in Africa [1]. In West Africa, the demand for rice is increasing at a rate of 6% per annum, the highest in the world [1]. Most of this demand is met by imports. Imported rice has taken over the markets in West Africa because of low production levels and failure of the rice industry to meet the grain quality standards demanded by consumers [1–3]. Rice cooking quality is mainly controlled by its starch properties. Starch has diverse characteristics including apparent amylose content (AAC), gelatinization temperature (GT), pasting viscosity [4]. Different products require rice with specific starch properties. A wide range of variation in rice starch characteristics is therefore required to meet the varied needs of processors and consumers. The genetic diversity of starch physicochemical properties of 56 waxy rices have been studied [5]. The authors found wide diversity in all the parameters studied which included retro-gradation properties tested by differential scanning colorimetry (DSC), pasting viscosity tested by rapid visco- analyzer (RVA), and flour swelling volume. They concluded that screening for waxy rice with desirable starch properties for specific food uses can be accomplished by using paste Correspondence: Dr. Maxwell Darko Asante, Council for Scientific Industrial Research-Crops Research Institute, P. O. Box 3785, Kumasi, Ghana E-mail: mdasante@gmail.com Fax: þ233-3320 60396 Abbreviations: AAC, apparent amylose content; CPV, cool paste viscosity; GBSS, granule bound synthase; GT, gelatinization temperature; HPV, hot paste viscosity; PV, peak viscosity DOI 10.1002/star.201300058 Starch/Stärke 2013, 65,1–7 1 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.starch-journal.com