Adaptability of a U.S. purple-fleshed sweetpotato breeding population in Uganda

Purple-fleshed sweetpotato varieties are important for their nutraceutical value due primarily to their high anthocyanin content. These varieties also often have high dry matter content preferred by consumers and processors in sub-Saharan Africa. However, improved purple-fleshed sweetpotatoes are not available in Uganda. This study was conducted to evaluate the adaptability of purple-fleshed sweetpotato genotypes for storage root yield, dry matter and anthocyanin content in Uganda. A bi-parental population of 159 clones from the cross NCP06-020 NC09-188 introduced to Uganda from North Carolina State University was evaluated with three local checks in two sites and two seasons in Uganda. The trials were planted in two locations using alpha lattice design with two replicates and five sweetpotato vine cuttings per genotype. Storage roots and vines were harvested after five months and the agronomic characteristics were recorded. Dry matter and anthocyanin content of storage roots were analysed after harvesting. The mean storage root yield of clones across the two locations was 37.8 t/ha and 24.2 t/ha in the first season (2015A) and second season (2015B); respectively, with an overall mean of 31.0 t/ha. Storage root dry matter content ranged from 21.5 to 33.7% across locations and seasons with an overall mean of 29.1%. Storage root anthocyanin content across the two locations ranged from 0 to 12.6 mg/100g FW with the overall mean of 3.9 mg/100g FW. A total of ten genotypes showed significantly stable performance (P <= 0.001) across two locations and two seasons. Highly significant difference between genotypes for dry matter content, anthocyanin content and total storage root yields revealed significant genetic variability among the tested genotypes, which can be exploited for future crop improvement.