Comparative genomic prediction of resistance to Fusarium wilt (Fusarium oxysporum f. sp. niveum race 2) in watermelon: parametric and nonparametric approaches.

Complex traits influenced by multiple genes pose challenges for marker-assisted selection (MAS) in breeding. Genomic selection (GS) is a promising strategy for achieving higher genetic gains in quantitative traits by stacking favorable alleles into elite cultivars. Resistance to Fusarium oxysporum f.

Mapping and validation of Fusarium wilt race 2 resistance QTL from Citrullus amarus line USVL246-FR2.

Fon race 2 resistant QTLs were identified on chromosomes 8 and 9. Families homozygous for resistance alleles at a haplotype of three KASP markers had 42% lower disease severity than those with susceptible alleles in an independent, interspecific validation population confirming their utility for introgression of Fusarium wilt resistance. Fusarium oxysporum f.

Genome-Wide Association Mapping and Genomic Prediction of Fusarium Wilt Race 2 Resistance in the USDA Collection.

Fusarium wilt caused by f. sp. () race 2 is a serious disease in watermelon and can reduce yields by 80%.

Genome-Wide Association Study of Resistance to in the USDA Collection of .

Pseudomonas leaf spot (PLS), caused by pv. , is an emerging disease of watermelon in the United States with the potential to severely reduce yield under humid conditions. The genetic basis of resistance to this disease is not known and no resistant germplasm is available.

QTL mapping of resistance to Pseudoperonospora cubensis clade 2, mating type A1, in Cucumis melo and dual-clade marker development.

This is the first identification of QTLs underlying resistance in Cucumis melo to an isolate of Pseudoperonospora cubensis identified as Clade 2/mating type A1. Pseudoperonospora cubensis, causal organism of cucurbit downy mildew (CDM), causes severe necrosis and defoliation on Cucumis melo (melon). A recombinant inbred line population (N = 169) was screened against an isolate of P.

First Report of Bacterial Leaf Spot on Spinach () Caused by sp. in South Carolina.

A large grower of Brassica leafy greens and spinach in South Carolina observed a severe outbreak of leaf spot on 150 hectares of spinach (Spinacia oleracea) in Orangeburg County, SC in 2013. The entire field was lost due to the outbreak. Symptoms appeared on 8-week old plants as tan to white necrotic spots with black centers, water-soaking and no discernable chlorotic borders.

Graph-based pangenomics maximizes genotyping density and reveals structural impacts on fungal resistance in melon.

The genomic sequences segregating in experimental populations are often highly divergent from the community reference and from one another. Such divergence is problematic under various short-read-based genotyping strategies. In addition, large structural differences are often invisible despite being strong candidates for causal variation.

Distinct Genomic Loci Underlie Quantitative Resistance to Galling and Reproduction in .

is a virulent species of root-knot nematode that threatens watermelon () production in the southeastern United States. There are no known sources of root-knot nematode resistance in cultivated . Specific genotypes of a wild watermelon relative, , are resistant against but the genetics that underly this resistance are still unknown and it is not clear that this same resistance will be effective against .

CuGenDBv2: an updated database for cucurbit genomics.

The Cucurbitaceae (cucurbit) family consists of about 1,000 species in 95 genera, including many economically important and popular fruit and vegetable crops. During the past several years, reference genomes have been generated for >20 cucurbit species, and variome and transcriptome profiling data have been rapidly accumulated for cucurbits. To efficiently mine, analyze and disseminate these large-scale datasets, we have developed an updated version of Cucurbit Genomics Database.

Genome-Wide Association Analysis of Resistance to in Citron Watermelon.

Cultivated sweet watermelon () is an important vegetable crop for millions of people around the world. There are limited sources of resistance to economically important diseases within . , whereas has a reservoir of traits that can be exploited to improve .

Broad Resistance to Post-Harvest Fruit Rot in USVL Watermelon Germplasm Lines to Isolates of Across the United States.

Watermelon is an important cucurbit vegetable crop grown in most of the United States. Phytophthora fruit rot of watermelon caused by has been a major factor, limiting production for the past 15 years in the southeastern United States. The U.

Quantitative Trait Loci Mapping of Resistance to Powdery Mildew Race 1 in a Recombinant Inbred Line Population of Melon.

Powdery mildew, caused by the fungus , is one of the most important diseases of melon. Although there are several pathogenic races of , race 1 is the predominant race in South Carolina and in other parts of the United States. We used a densely genotyped recombinant inbred line melon population for traditional quantitative trait loci (QTL) mapping, to identify two major ( and ) and two minor ( and ) QTLs (named according to race - chromosome number) associated with resistance to race 1.

QTL mapping of resistance to Pseudoperonospora cubensis clade 1, mating type A2, in Cucumis melo.

This is the first identification of QTLs underlying resistance to Pseudoperonospora cubensis in Cucumis melo using a genetically characterized isolate. Pseudoperonospora cubensis, causal organism of cucurbit downy mildew (CDM), is one of the largest threats to cucurbit production in the eastern USA. Currently, no Cucumis melo (melon) cultivars have significant levels of resistance.

QTL Mapping and Marker Development for Tolerance to Sulfur Phytotoxicity in Melon ().

Elemental sulfur is an effective, inexpensive fungicide for many foliar pathogens, but severe phytotoxicity prohibits its use on many melon varieties. Sulfur phytotoxicity causes chlorosis and necrosis of leaf tissue, leading to plant death in the most sensitive lines, while other varieties have little to no damage. A high-density, genotyping-by-sequencing (GBS)-based genetic map of a recombinant inbred line (RIL) population segregating for sulfur tolerance was used for a quantitative trait loci (QTL) mapping study of sulfur phytotoxicity in melon.

QTL mapping of resistance to Fusarium oxysporum f. sp. niveum race 2 and Papaya ringspot virus in Citrullus amarus.

A Citrullus amarus mapping population segregating for resistance to Fusarium oxysporum f. sp. niveum race 2 and Papaya ringspot virus was used to identify novel QTL, important for the improvement in watermelon disease resistance.

Genome of 'Charleston Gray', the principal American watermelon cultivar, and genetic characterization of 1,365 accessions in the U.S. National Plant Germplasm System watermelon collection.

Years of selection for desirable fruit quality traits in dessert watermelon (Citrullus lanatus) has resulted in a narrow genetic base in modern cultivars. Development of novel genomic and genetic resources offers great potential to expand genetic diversity and improve important traits in watermelon. Here, we report a high-quality genome sequence of watermelon cultivar 'Charleston Gray', a principal American dessert watermelon, to complement the existing reference genome from '97103', an East Asian cultivar.

QTL Mapping Identifies Novel Source of Resistance to Fusarium Wilt Race 1 in .

Fusarium wilt race 1, caused by the soilborne fungus Schlechtend.: Fr. f.

Genome-Wide Association Study of Resistance to in the USDA Pepper () Collection.

Bacterial spot species cause significant disease outbreaks on tomato and pepper in tropical and subtropical regions throughout the world. Host resistance has been one of the key components of integrated disease management approaches to mitigate plant pathogens. Although a number of resistance genes have been identified in pepper against bacterial spot xanthomonads, emergence of bacterial spot pathogen variants capable of overcoming these sources and changing pathogen distributions reinforce the importance of identifying novel candidates to incorporate into breeding programs.

QTL mapping of resistance to bacterial fruit blotch in Citrullus amarus.

Six QTLs were associated with affected leaf area in response to inoculation with Acidovorax citrulli in a recombinant inbred line population of Citrullus amarus. Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits, has the potential to devastate production of watermelon and other cucurbits. Despite decades of research on host-plant resistance to A.

Genetic Diversity and Population Structure of the USDA Sweetpotato () Germplasm Collections Using GBSpoly.

Sweetpotato () plays a critical role in food security and is the most important root crop worldwide following potatoes and cassava. In the United States (US), it is valued at over $700 million USD. There are two sweetpotato germplasm collections (Plant Genetic Resources Conservation Unit and US Vegetable Laboratory) maintained by the USDA, ARS for sweetpotato crop improvement.

Construction of a genome-anchored, high-density genetic map for melon (Cucumis melo L.) and identification of Fusarium oxysporum f. sp. melonis race 1 resistance QTL.

Four QTLs and an epistatic interaction were associated with disease severity in response to inoculation with Fusarium oxysporum f. sp. melonis race 1 in a recombinant inbred line population of melon.

Quantitative trait loci mapping of heat tolerance in broccoli (Brassica oleracea var. italica) using genotyping-by-sequencing.

Five quantitative trait loci and one epistatic interaction were associated with heat tolerance in a doubled haploid population of broccoli evaluated in three summer field trials. Predicted rising global temperatures due to climate change have generated a demand for crops that are resistant to yield and quality losses from heat stress. Broccoli (Brassica oleracea var.

Mapping Resistance to Alternaria cucumerina in Cucumis melo.

Infection with Alternaria cucumerina causes Alternaria leaf blight (ALB), a disease characterized by lesion formation on leaves, leading to substantial yield and quality losses in Cucumis melo (melon). Although fungicides are effective against ALB, reduction in the frequency of application would be economically and environmentally beneficial. Resistant melon lines have been identified but the genetic basis of this resistance has not been determined.

A GBS-SNP-based linkage map and quantitative trait loci (QTL) associated with resistance to Fusarium oxysporum f. sp. niveum race 2 identified in Citrullus lanatus var. citroides.

A major QTL for resistance to Fusarium oxysporum f. sp. niveum race 2 was mapped to a narrow 1.