The future of US vegetable production depends on the continued genetic improvement and development of new superior cultivars. Extensive use of pesticides, water and energy are becoming prohibitively costly, both to producer and to the ecosystems. Increased yield potential and improved quality are imperative for US growers to compete in the world market. Strategies such as the application of DNA markers to breeding and selection programs and the introduction of novel genes into elite cultivars through genetic engineering and mutation analysis are needed to accelerate development of new superior vegetable cultivars. Initial focus is on genetic improvement of pepper and watermelon using DNA marker technology and genetic engineering.
Peppers*: The genus Capsicum is a diverse group of nightshade plants whose fruit is commonly known as a pepper. There are 27 described species; some of which are used as spices, and medicinesFive species are domesticated, with C. annuum (jalapenos and bell peppers), C. chinense (habaneros) and C. frutenscens (Tabasco) being the most commercially signifi cant. Known as the annuum-chinense-frutescens complex, these Capsicum species have signifi cant variation for important traits including fruit traits, pest resistance, and tolerance to environmental adversities such as heat, cold and drought. DNA-based genetic markers are playing a critical, and increasing, role in the development of superior cultivars that combine the favorable qualities conditioned by this diverse elite germplasm. Wild Capsicum germplasm also harbors many valuable traits however, the transfer of genes from wild to cultivated species is time consuming and not always successful. Current research mainly focuses on the DNA markers that assess the introgression of favorable genes into cultivated peppers and will greatly accelerate these efforts.
Watermelon*: Cousin to the cucumber, watermelon (Citrullus Lanatus) has been cultivated for thousands of years and has been improved by domestication and formal plant breeding. Being the most-consumed melon in the U.S with a total production value of $284 million there is increasing demand for product quality, disease resistance and other agriculturally important traits. Current research is focused on application of DNA marker technology for genetic improvement of these traits in watermelon.
Sweet Potato*: In the United States, the sweet potato an important, fundamental food in the American diet; and has rooted cultural signifi cance. With 13 states involved in commercial production, annual crop value is nearly $250 million. The research proposed focus to build extensive genomic infrastructure for this important crop. The sweet potato is one of the neglected crop genomes in terms of allocation of public funding and other resources. The current project is a multiinstitutional consortium to address all the problems faced by the conventional breeder to improve sweet potato traits such as quality and disease resistance.
Cucurbit: Cucurbit species include a variety of high value crops (e.g., melons, pumpkin, squash, watermelon, and cucumber) that play an important role both in local diets and as export crops in the U.S. This research is to development comparative genetic maps and DNA marker resources for melon, pumpkin, squash, cucumber and watermelon; with special reference to fruit quality genes, disease resistance gene analog primers, and cloned, nutraceutically important genes from other crop species. This project is a collaborative effort with Texas A&M University.
* Funding for these projects is provided by USDA CSREES
Research Scientists:
Dr. Padma Nimmakayala
766-3258
Dr. Umesh Ready
766-3066
