Genome-Wide Association Mapping of Oil Content and Seed-Related Traits in Shea Tree (<i>Vitellaria paradoxa</i> subsp. <i>nilotica</i>) Populations
Juventine Boaz Odoi,
Emmanuel Amponsah Adjei,
Michael Teye Barnor,
Richard Edema,
Samson Gwali,
Agyemang Danquah,
Thomas Lapaka Odong,
Prasad Hendre
Affiliations
Juventine Boaz Odoi
National Forestry Resources Research Institute (NaFORRI), Agricultural Research Organization (NARO), Kampala P.O. Box 1752, Uganda
Emmanuel Amponsah Adjei
School of Agricultural Sciences (SAS), College of Agricultural and Environmental Sciences (CAES), Makerere University, Kampala P.O. Box 7062, Uganda
Michael Teye Barnor
Cocoa Research Institute of Ghana (CRIG), Bole P.O. Box BL 41, Ghana
Richard Edema
School of Agricultural Sciences (SAS), College of Agricultural and Environmental Sciences (CAES), Makerere University, Kampala P.O. Box 7062, Uganda
Samson Gwali
National Forestry Resources Research Institute (NaFORRI), Agricultural Research Organization (NARO), Kampala P.O. Box 1752, Uganda
Agyemang Danquah
West Africa Center for Crop Improvement (WACCI), College of Basic and Applied Sciences, University of Ghana, Accra P.O. Box LG 25, Ghana
Thomas Lapaka Odong
School of Agricultural Sciences (SAS), College of Agricultural and Environmental Sciences (CAES), Makerere University, Kampala P.O. Box 7062, Uganda
Prasad Hendre
Center for International Research in Forestry—International Center for Research in Agroforestry (CIFOR—ICRAF), United Nations Avenue, Girigiri, P.O. Box 30677, Nairobi 00100, Kenya
Shea tree (Vitellaria paradoxa) is an important fruit tree crop because of its oil used for cooking and the industrial manufacture of cosmetics. Despite its essential benefits, quantitative trait loci linked to the economic traits have not yet been studied. In this study, we performed association mapping on a panel of 374 shea tree accessions using 7530 Single-Nucleotide Polymorphisms (SNPs) markers for oil yield and seed-related traits. Twenty-three SNP markers significantly (−log10 (p) = 4.87) associated with kernel oil content, kernel length, width, and weight were identified. The kernel oil content and kernel width had the most significant marker–trait associations (MTAs) on chromosomes 1 and 8, respectively. Sixteen candidate genes identified were linked to early induction of flower buds and somatic embryos, seed growth and development, substrate binding, transport, lipid biosynthesis, metabolic processes during seed germination, and disease resistance and abiotic stress adaptation. The presence of these genes suggests their role in promoting bioactive functions that condition high oil synthesis in shea seeds. This study provides insights into the important marker-linked seed traits and the genes controlling them, useful for molecular breeding for improving oil yield in the species.
