Location: Vegetable Research
Project Number: 6080-22000-027-000-D
Project Type: In-House Appropriated
Start Date: Sep 30, 2015
End Date: Aug 31, 2020
Objective:
1. Identify and characterize host plant resistance genes and develop germplasm lines of sweetpotato and watermelon that are resistant or tolerant to economically important insect pests of important vegetable crops, and develop germplasm lines adapted to low input, sustainable production systems [NP304, Component 3, Problem Statement 3A2].
1.A. Characterize watermelon germplasm lines with resistance to the sweetpotato whitefly and incorporate resistance factors into advanced watermelon breeding lines.
1.B. Identify and characterize resistance genes and genotypes of sweetpotato with resistance to soil insect pests, elucidate mechanisms of pest resistance, and develop germplasm clones that are resistant to soil insect pests and have good horticultural characteristics.
1.C. Identify sweetpotato clones tolerant of weed interference and/or whitefly-transmitted viruses that are superior to conventional cultivars for organic and sustainable production.
2. Develop methods to improve control of insect pests, especially whiteflies, in vegetable production systems, and identify the effects of biotic and abiotic factors on populations of pests and their biological control agents, and on whitefly:host plant:virus interactions. This objective will be enhanced by developing and applying novel genomics-based technologies to manage whiteflies and whitefly-transmitted viruses in vegetable crops.
2.A. Determine the effect of biotic and abiotic factors on populations of biological control agents of whiteflies in vegetable production systems.
2.B. Determine the impact of factors associated with climate change on whitefly:host plant:virus interactions and whitefly endosymbionts.
2.C. Investigate sustainable management approaches for pests in vegetable crops, including detection of pest populations such as pickleworms.
Approach:
Conduct laboratory, greenhouse and field experiments to identify sources of resistance and evaluate genetic populations to determine resistance against the sweetpotato whitefly in watermelon and against soil insect pests, weeds and whitefly-transmitted virus in sweetpotato. Assay chemical and physical mechanisms of resistance to pests using gas chromatography-mass spectrometry (GC-MS), portable “electronic nose,” Y-tube olfactometers, and other assays. Use PCR-markers and other genomic technologies, such as genotype by sequencing, to identify sequences linked to the studied characters and to locate controlling genes on linkage maps. Cross appropriate germplasm to facilitate the incorporation of resistance into advanced breeding lines or new cultivars. Assess the competitive advantage against weeds of sweetpotato genotypes with more vigorous growth habits in comparison to less competitive conventional cultivars, identify competitive genotypes with good horticultural quality, and evaluate them as a component in integrated management systems for conventional and organic growers. Use a recurrent mass selection breeding approach to generate sweetpotato clones with high levels of resistance and good horticultural characteristics. Continue ongoing searches for new resistances or tolerances among watermelon and sweetpotato accessions from the U.S. Plant Introduction System and other collections. Make improved germplasm available for use by the vegetable industry. Investigate the influence of climate and biotic factors on insect populations by using environmental chambers and field cages. Assess the behavior and ecology of pickleworms and other pests for their control by the development of new formulations and ratios of the pheromone components and testing them in flight tunnel and field environments. Study the epidemiology of whitefly-transmitted Sweet potato leaf curl virus in sweetpotato using biological assays and molecular detection techniques, including real-time (RT)-PCR and quantitative (q)PCR.
