Evaluation of purple-fleshed sweetpotato genotypes for root yield, quality and pest resistance

Abstract

Production of purple-fleshed sweetpotatoes, source of anthocyanins, pigments with high antioxidant activities, is expected to be extended during the upcoming years, as there is a strong trend to market products promising improved health. This study aimed to evaluate yield, postharvest quality and pest resistance of roots of purple-fleshed sweetpotatoes. Six genotypes (BGBD 0005, BGBD 0080, BGBD 1261, BGBD 1399, BGBD 1402 and BGBD 1405) and the cultivars Beauregard and Brazlândia Roxa as controls were evaluated during two seasons 2018 (Experiment 1) and 2019 (Experiment 2), in Brasília-DF, Brazil. The experiments were conducted in a complete randomized blocks design with four replications, with experimental plots consisting of two rows of six plants. Roots were harvested about 140 days after planting and evaluated for yield, appearance, insect damage and quality characteristics as soluble solids, dry matter and color. All genotypes showed roots with good resistance to soil insects. The highest commercial production of genotypes BGBD 1261, BGBD 0005, and BGBD 1405 associated to quality traits (dry matter content and soluble solids) and pest resistance, showed their potential for being released as cultivars or to be used in breeding programs.

Performance of sweet potato genotypes in Brazilian regions

“…Clones 8 and 33 showed the largest roots in both years. The average root length for Beauregard, 15.2 cm, is similar to results of a previous study 15.1 cm (Melo et al, 2020). In our study, this trait was negatively correlated with CY (correlation of -0.75) (Table 6).…”

“…The average CY for this first set of experiments was 23.60 t ha -1 (Table 3), similar to those obtained in other studies with improved materials (Andrade Junior, 2009;Melo et al, 2020) and well above the average Brazilian yield of 14.07 t ha -1 (IBGE, 2021).…”

“…Studies on cultivar Beauregard conducted in North Carolina and Tennessee (the United States) showed total yields ranging from 25.5 to 34.9 t ha -1 in the former and 40 t ha -1 in the latter obtained at 132 and 126 days after planting, respectively (Nwosisi et al, 2017;Schultheis et al, 1999). Similar results were found in Brazil where commercial root yield ranged from 28.18 to 35.68 t ha -1 for the Beauregard cultivar (Melo et al, 2020). These values were lower than the average (61.4 t ha -1 ) of the four present studies (Table 4), showing that yield potential for Beauregard in some Brazilian regions can be even greater than that described in the literature.…”

“…These values are in accordance with the ideal size for the market, which ranges from 200 to 400 g (Miranda, 1989). Melo et al (2020) found a commercial root weight average of 321.5 g for Beauregard in Brasilia-DF, Brazil. As cultural and climatic conditions in Brazil vary greatly across its territory, the ideal harvest time for sweet potato and therefore the ideal root size may also vary according to preferences of consumers in local markets (Melo et al, 2020).…”

“…Therefore, this association does not seem to be a rule, but dependant on the genotypes evaluated, possibly with DIAM more important than COMP to CY. In general, consumers prefer fusiform shapes of 1/3 diameter/length (Melo et al, 2020). Thus, the best expected length is on average 15.3 cm for the average diameter of 5.1 cm.…”