2017 ASHS Annual Conference

Ten sweetpotato accessions/ cultivars were evaluated for yield, resistance to pests, and quality in field trials in Pepeekeo, Hawaii. Thirty cuttings of each accession/ cultivar were planted at a spacing of 0.3 m in a hill that was 1.5 x 9.1 m and blocked over time due to limited availability of space. In the first two field trials, local cultivars planted were Okinawan, Mokuau, and Kona B, as well as accessions 531094, 566613 (Beauregard), 573309, 573330, 595199 (Darby), 634398 (Pelican Processor), and 634399 (Picadito). Yields of ‘Mokuau’ and ‘Kona B’ were too low and they were replaced in the latter three field trials with two new cultivars from Louisiana State University Agricultural Center (Murasaki-29 and 0821P). Five trials were planted on May 2014, October 2014, February 2015, 15 July 2015, and January 2016. Plots were harvested from 4.5 to 6 months after planting. Storage roots were graded according to State of Hawaii standards, and categorized as Grade AA, A, B, and off-grade. Marketable yields combined storage roots in Grades AA, A, and B. In addition, injuries of storage roots in each category were estimated due to infestations of sweetpotato weevil [Cylas formicarius elegantulus (Coleoptera: Brentidae)]. Finally, sugar concentrations, anthocyanins, and β-carotene contents were measured in storage roots. Accessions/ cultivars differed significantly in marketable fresh weight yields, with 0821P having the greatest marketable yields. However, ‘0821P’ also had the greatest incidence of damage due to weevils, perhaps due to its growth habit of a tight cluster of storage roots located close to the soil surface. Accessions/ cultivars also differed significantly in sugar concentrations (fructose, glucose, sucrose, maltose, and total sugars). Concentration of sucrose was highest among mono- and di-saccharides analyzed, and ranged from 25 to 68 mg gfw^-1. ‘Beauregard’ had the highest sucrose concentration and total sugars. Purple-fleshed cultivars (Okinawan and 0821P) contained total monomeric anthocyanins that ranged from 34 to 37 mg 100 gdw^-1. Orange-fleshed cultivars (Beauregard and Darby) contained β-carotene that ranged from 5485 to 8302 ug 100 gfw^-1. Results from these field trials demonstrate healthful benefits of purple-fleshed and orange-fleshed sweetpotato cultivars, as well as provide yield information to growers interested in producing new cultivars.