Sweetpotato (Ipomoea batatas var. batatas) cultivar trials on Hawaii Island

Authors: MIYASAKA, SUSAN - University Of Hawaii; Wall, Marisa; LABONTE, DON - Louisiana State University; CLARK, CHRISTOPHER - Louisiana State University; ARAKAKI, ALTON - University Of Hawaii

Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2019
Publication Date: 12/1/2019
Citation: Miyasaka, S., Wall, M.M., Labonte, D., Clark, C., Arakaki, A. 2019. Sweetpotato (Ipomoea batatas var. batatas) cultivar trials on Hawaii Island. HortTechnology. 29(6): 967-975. https://doi.org/10.21273/horttech04387-19.
DOI: https://doi.org/10.21273/horttech04387-19

Interpretive Summary: In a series of field trials, sweetpotato cultivars and advanced accessions were grown on Hawaii Island and evaluated for yield, resistance to insect pests, consumer acceptance, and quality. The overall goal was to identify alternative cultivars for commercial production, as well as superior sources of germplasm for breeding high yielding, nutritious sweetpotatoes with tolerance to insect pests under tropical conditions. Cultivar LA 08-21p had the greatest marketable yield that was almost six times greater than the commercial cultivar Okinawan, both purple-fleshed cultivars with anthocyanins. However, LA 08-21p also had the highest incidence of sweetpotato weevil damage. Beauregard had the highest sugar and ß-carotene concentrations, although Okinawan was rated highest for sweetness and overall acceptance by a sensory panel. 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.

Technical Abstract: Ten sweetpotato accessions/ cultivars were evaluated for yield, resistance to pests, and quality in five field trials replicated over time during 2014 to 2016 in Pepeekeo, Hawaii. One block each was planted on May 2014, October 2014, February 2015, July 2015, and January 2016. Plots were harvested at 4.5 to 6 months after planting. 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. In the first two field trials, local cultivars/ landraces 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 low and they were replaced in the latter three field trials with two new cultivars from Louisiana State University Agricultural Center (Murasaki-29 and LA 08-21p). At harvest, 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 ß-carotene contents were measured in storage roots. Accessions/ cultivars/ landraces differed significantly in marketable fresh weight yields, with LA 08-21p having the greatest marketable yields. However, LA 08-21p also had the greatest incidence of damage due to sweetpotato weevil, perhaps due to its growth habit of a tight cluster of storage roots located close to the soil surface. Accessions/ cultivars/ landraces 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 LA 08-21p) contained total monomeric anthocyanins that ranged from 34 to 37 mg'100 gdw-1. Orange-fleshed cultivars (Beauregard and Darby) contained ß-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.