Response of accessions within tomato wild species, Solanum pimpinellifolium to late blight

Abstract

Late blight (LB), caused by the oomycete Phytophthora infestans, is one of the most devastating diseases of the cultivated tomato (Solanum lycopersicum) worldwide. Most commercial cultivars of tomato are susceptible to LB. Previously, three major LB resistance genes (Ph-1, Ph-2, Ph-3) were identified and incorporated into a few commercial cultivars of tomato. Reduced effectiveness and potential breakdown of the resistance genes has necessitated identification, characterization and utilization of new sources of resistance. We evaluated the response of 67 accessions of the wild tomato species, S. pimpinellifolium to LB, under multiple field and greenhouse (GH) conditions and compared them with six control genotypes. Sixteen accessions were identified with strong LB resistance in both field and GH experiments. However, 12 accessions exhibited resistance similar to a control line which was homozygous for Ph-2 + Ph-3. Genotyping accessions with molecular markers for Ph-2 and Ph-3 were not conclusive, indicating that resistance in these accessions could be due to these or other resistance genes. Strong correlations were observed between field and GH disease response and between foliar and stem infection.

Genetic analysis of late blight resistance in Solanum pimpinellifolium accession PI 270441: Heritability and response to selection

“…Twelve accessions were identified that exhibited strong LB resistance in field, glasshouse and detached‐leaflet experiments. One S. pimpinellifolium accession, PI 270441, showed LB resistance similar to a commercial cultivar containing Ph‐2 + Ph‐3 resistance genes combined (Foolad, Sullenberger, & Ashrafi, ; Foolad, Sullenberger, Ohlson, & Gugino, ). This accession was also shown to be highly resistant against P. infestans clonal lineages US‐13 (one isolate), US‐14 (six isolates) and US‐23 (one isolate) (Foolad et al., ).…”

“…One S. pimpinellifolium accession, PI 270441, showed LB resistance similar to a commercial cultivar containing Ph‐2 + Ph‐3 resistance genes combined (Foolad, Sullenberger, & Ashrafi, ; Foolad, Sullenberger, Ohlson, & Gugino, ). This accession was also shown to be highly resistant against P. infestans clonal lineages US‐13 (one isolate), US‐14 (six isolates) and US‐23 (one isolate) (Foolad et al., ). In the present study, the genetic basis of LB resistance in PI 270441 was examined by assessing the h 2 of resistance, determining response to selection for resistance, and estimating the number of loci contributing to the resistance.…”

Requeima do tomateiro: Severidade e perdas em diferentes cultivares em sistema orgânico de produção

“…Segundo Batista et al (2006) a utilização de cultivares resistentes é o método ideal de controle desta doença. Entretanto, apesar da existência de genes de resistência, a maioria das cultivares de tomateiro é suscetível a requeima (FOOLAD et al, 2014;NOWICKI et al, 2013). Diante disso, estudos de caracterização e avaliação de cultivares de tomateiro sob manejo orgânico em condições de ambiente favorável à requeima são necessários visando a identificação daquelas mais adaptadas às especificidades deste sistema.…”

Potencial de hibridação entre acessos de tomateiro para pré-melhoramento quanto à resistência à requeima

“…de Bary, agente etiológico da requeima, é um dos patógenos mais destrutivos do tomateiro (Solanum lycopersicum L.) cultivado, o que resulta em perdas significativas na cultura (Nowicki et al, 2012). Atualmente, a maioria das cultivares de tomateiro é suscetível à requeima, e o manejo da doença é realizado principalmente por meio da aplicação de fungicidas (Foolad et al, 2014).…”

“…Spooner (Abreu et al, 2008) e Solanum pimpinellifolium (Foolad et al, 2014). Contudo, quando as fontes são da mesma espécie que se deseja melhorar, há maior facilidade de cruzamentos para transferência de genes (Abreu et al, 2008) e recuperação mais rápida das características agronômicas desejadas (Adalid et al, 2012).…”