Abstract Detail

Crops and Wild Relatives

Nicolao, Rodrigo [1], Marques Castro, Caroline [2], Heiden, Gustavo [2].

Tuber glycoalkaloid content of wild accessions from Embrapa Potato Genebank.

Wild potatoes (Solanum sect. Petota, Solanaceae) are a valuable reservoir of novel traits for breeding. However, wild genotypes can also present undesirable traits such as high glycoalkaloid content in tubers. Thus, evaluation of accessions conserved at genebanks for content measurement of these compounds are priority steps to support information-based decisions in pre-breeding efforts for introgression of target traits in potato (S. tuberosum). Embrapa Clima Temperado, a base of the Brazilian Agricultural Research Corporation in Pelotas, Rio Grande do Sul, Brazil, hosts the national potato genebank. We evaluated the total glycoalkaloids content (mg/100 g) of 48 accessions from S. chacoense (13), S. commersonii (25), S. malmeanum (10) and S. tuberosum commercial cultivars (02) as controls. Plants grown between March and July 2020 (autumn/winter) in greenhouse had their tubers harvested and processed as longitudinal sections of whole tubers without peeling. Samples were ground and dissolved in chloroform/methanol (2:1 v/v), followed by a liquid-liquid extraction with 0.8% Na2SO4. The phase containing water and total glycoalkaloids was placed in a water bath at 70°C until complete evaporation. The extract was resuspended in 10 mL of 5% acetic acid, and the pH adjusted to 10 with NH4OH. After heating at 70°C for 30 minutes, the samples were centrifuged for 20 minutes at 9,000 rpm. The precipitate was dried in a water bath at 70°C and redissolved in 1 mL of H3PO4 (0.5mol/L). 10 mL of Clarke's reagent was added and after 30 minutes the colorimetric determination of total glycoalkaloids was performed in a spectrophotometer at 600 nm. The calibration curve was performed with the α-solanine standard at concentrations from 50 μg/mL to 1,000 μg/mL. The measured tuber glycoalkaloid contents in S. chacoense accessions were 0.32 (BGB464), 0.46 (BGB472), 0.59 (BGB467), 0.87 (BGB488), 1.03 (BGB469), 1.54 (BGB489), 1.94 (BGB086), 12.11 (BGB444), 17.41 (BGB463), 17.60 (BGB468), 20.00 (BGB466), 26.08 (BGB451), 34.42 (BGB462). For S. commersonii accessions, the lowest value was 0.88 (BGB450), followed by 0.92 (BGB042), 1.03 (BGB040), 1.17 (BGB067), 1.26 (BGB077), 1.30 (BGB003), 1.35 (BGB461), 1.37 (BGB068), 1.73 (BGB033), 2.25 (BGB460), 2.55 (BGB009), 3.13 (BGB459), 3.32 (BGB053), 3.90 (BGB012), 4.61 (BGB037), 5.09 (BGB085), 5.59 (BGB455), 7.00 (BGB059), 7.92 (BGB055), 11.56 (BGB453), 12.32 (BGB008), 12.43 (BGB014), 16.14 (BGB001), 16.21 (BGB045), 17.76 (BGB029). In S. malmeanum, the lowest value was 0.21 (BGB471), followed by 0.85 (BGB443), 2.93 (BGB080), 4.27 (BGB448), 4.32 (BGB081), 4.70 (BGB015), 11.58 (BGB447), 16.04 (BGB084), 19.09 (BGB021), 19.28 (BGB017). The S. tuberosum commercial cultivars content was 0.39 (Ana) and 0.63 (Bel). The maximum amount of glycoalkaloids content in commercial potato tubers allowed by international legislation is 20 mg/100g. All accessions of S. commersonii and S. malmeanum and 11 accessions of S. chacoense are within the safety limits, so glycoalkaloid content in these accessions is not a significant constraint for their use in pre-breeding. However, two S. chacoense accessions have levels of glycoalkaloids exceeding the food standards and their use in pre-breeding should consider this constraint and target the decrease of tubers glycoalkaloid contents to avoid dragging this undesirable trait when other quality traits are targeted.

1 - Universidade Federal de Pelotas, Agronomy/Plant Breeding, Capão do Leão, RS, 96160-000
2 - EMPBRAPA Clima Temperado (Brazil)

Wild relatives

Presentation Type: Poster
Number: PCW008
Abstract ID:786
Candidate for Awards:None

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