Abstract Detail

Crops and Wild Relatives

Nicolao, Rodrigo [1], Castro Marques, Caroline [2], Heiden, Gustavo [3].

Breeding system of Solanum malmeanum: pathways to unlock the barriers of a wild relative to broaden the potato crop genetic basis.

Solanum malmeanum  is a South American wild potato which harbors agronomical traits desirable to broad the genetic basis of the potato crop. This species is in the  S. tuberosum  tertiary gene pool, assigned as 1EBN (Endosperm Balance Number). So, it is hypothesized as cross-incompatible 2EBN and 4EBN species, the later including the potato crop itself. For an efficient use of potato genetic resources conserved at genebanks, it is necessary to characterize the germplasm according to the breeding system behavior. Then, data on its mode of reproduction could help to find pathways to overcome reproductive isolation, allowing through hybridizations the introgression of desirable traits in potato breeding programs. To move genebank conserved genotypes towards pre-breeding pipelines, this study characterizes 10 accessions (BGB015, BGB017, BGB021, BGB080, BGB081, BGB084, BGB446, BGB447, BGB448, BGB471) of  S. malmeanum  from Embrapa Clima Temperado Potato Genebank to evaluate pollen production and test the occurrence of parthenocarpy, apomixis, autogamy, allogamy, and evaluate response to reciprocal crossings with 2x 1EBN  S. commersonii  (BGB001), 2x 2EBN  S. chacoense  (BGB444), and the cultivated crop 4x 4EBN  S. tuberosum  (cultivar BRSANA and advanced breeding line C1750-15-95). The eight  S. malmeanum  diploid accessions (BGB015, BGB017, BGB021, BGB080, BGB446, BGB447, BGB448, BGB471) produced pollen, menwhile the two triploid accessions (BGB081, BGB084) did not. One accession (BGB448) produces parthenocarpic fruits lacking seeds. Apomixis is absent in all evaluated accessions. The eight diploids (BGB015, BGB017, BGB021, BGB080, BGB446 BGB447, BGB448, BGB471) are allogamous, while the two triploids (BGB081, BGB084) did not produce fruits in any treatment and crosses and, hence, only reproduce clonally. There are no autogamous  S. malmeanum  accessions, however, one self-compatible accession (BGB447) was identified through a mediated self-pollination treatment. The diploid accessions easily hybridize with 2x (1EBN)  S. commersonii  and produces fruits with normal seed development and good germination rate. Germination was 33%, when  S. malmeanum  is crossed as a female parent with  S. commersonii, and 41% when crossed as male parent with  S. commersonii. When diploid  S. malmeanum  accessions were crossed with 2x (2EBN)  S. chacoense,  the  seeds were malformed and had a low germination percentage (13.6%), conversely reciprocal crosses totally failed. The direct crosses between  S. malmeanum  and  S. tuberosum  of 4EBN group confirmed the expected cross-incompatibility. However, the partially successful results when crossed with  S. chacoense  (2EBN) suggests that other ways of introgression through indirect crosses mediated by bridge species could lead to alternative pathways to unlock its reproductive barriers.

1 - Universidade Federal de Pelotas, Agronomia, Capão do Leão, Pelotas, Rio Grande do Sul, 96010140, Brasil
2 - Embrapa Clima Temperado, Rodovia BR 392, km 78, Pelotas, RS, 403, Brasil
3 - Embrapa Clima Temperado, Herbarium ECT, Rodovia BR 392, km 78, Caixa Postal 403, Pelotas, RS, 96010-971, Brasil

Keywords:
crossability
Endosperm Balance Number (EBN)  
mode of reproduction  
interspecific crosses  
Crop wild relatives
Solanaceae.

Presentation Type: Poster
Session: P1, Crops and Wild Relatives Posters
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: P1CW004
Abstract ID:615
Candidate for Awards:None