Abstract Detail

Crops and Wild Relatives

Nicolao, Rodrigo [1], Campos, Aryane [2], Marcal, Saulo [2], Castro Marques, Caroline [3], Heiden, Gustavo [3].

DNA content and estimated ploidy of wild potatoes (Solanum chacoense, Solanaceae) from Embrapa Potato Genebank.

Solanum chacoense (potato secondary genepool) is an important source of genes for introgression of desirable traits in the allotetraploid potato crop (S. tuberosum) or for breeding at diploid level. This species has already contributed with quality traits such as resistance to cold-induced sweetening and increasing of dry matter content in tubers. It also has potential applications to the development of cultivars resistant to pests that affect the potato crop, as Colorado potato beetle (Leptinotarsa decemlineata), potato tuberworm (Phthorimaea operculella), and potato leafhopper (Empoasca fabae). Embrapa Clima Temperado, a base of the Brazilian Agricultural Research Corporation in Pelotas, Rio Grande do Sul, Brazil, hosts the national potato genebank and leads the institutional potato breeding program. Flow cytometry allows screening a large number of samples to estimate the DNA content and to characterize genetic variation of germplasm collections with applied uses for information-based decisions in plant breeding. Hence, we used flow cytometry to determine the DNA content (pg/2C) and estimate the ploidy level of 31 Embrapa Potato Genebank accessions of Solanum chacoense. Young fresh leaves were collected and had 30 mg samples fragmented in 700 μL WPB buffer solution. The solution was filtered through a nylon screen (50 μm), added with 25 μL of extraction buffer with 1 mg/mL of propidium iodide and 5 μL of RNase, followed by 1 hour in dark at room temperature. For each sample, 10.000 nuclei were analyzed using logarithmic scale, in flow cytometer CytoFLEX LX (Beckman Coulter). For each accession, three samples were read and the 2C content was calculated using the average peak of 3 replicates per sample and the internal standard (Pisum sativum leaves = 9.09 pg/2C). Only measures with coefficients of variation lower than 5% were considered. We inferred two levels of ploidy based on the analyzed accessions. DNA content (2C) varied between 1.65 and 2.56 pg in diploid accessions and between 2.89 and 2.98 in triploids. Inferred diploids (2x) are BGB083 (1.99 pg), BGB094 (2.05 pg), BGB095 (2.02 pg), BGB096 (1.99 pg), BGB097 (2.05 pg), BGB099 (2.08 pg), BGB100 (1.98 pg), BGB101 (1.90 pg), BGB103 (2.56 pg), BGB104 (2.07 pg), BGB105 (2.05 pg), BGB106 (2.17 pg), BGB108 (1.99 pg), BGB110 (2.14 pg), BGB111 (1.97 pg), BGB112 (2.01 pg), BGB113 (1.97 pg), BGB444 (2.07 pg), BGB462 (2.10 pg), BGB464 (2.04 pg), BGB466 (2.25 pg), BGB468 (1.99 pg), BGB469 (1.65 pg), BGB472 (2.06 pg), BGB488 (1.98 pg) and BGB489 (1.94 pg). Meanwhile, inferred triploids (3x) are BGB086 (2.98 pg), BGB463 (2.97 pg), BGB470 (2.89 pg) and BGB474 (2.92 pg). When comparing the flow cytometry data inferred ploidy with previously obtained morphological data we confirmed a correlation of morphological characters linked to ploidy and the results obtained, corroborating that accessions with overall smaller leaves, star-shaped corollas and bigger fruit are diploids and accessions with larger leaves, rotate corollas and smaller fruit or unable to set fruit are triploids. Next steps will compare these results with other techniques to estimate ploidy indirectly or directly, such as evaluation of leaf stomata density and size, or classic cytogenetics.

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

Wild relatives

Presentation Type: Poster
Number: PCW009
Abstract ID:827
Candidate for Awards:None

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