Integrated Fruit and Vegetable Research, GA

NON-TECHNICAL SUMMARY: One of the major production challenges for pepper, tomato, squash and other vine crop growers is a disease caused by Phytophthora capscici for which there is no control. This disease affects over half of the Georgia vegetable farm gate value. Part of this grant will fund research aimed at developing breeding lines resistant to P. capscici, particularly in pepper and squash by screening for resistant varieties and making crosses with identified germplasm. Traditional breeding and screening methods will be used to develop lines of these crops that are resistant to P. capscici. These lines will then be used by commercial seed companies to produce resistant varieties. Over half the costs of producing vegetables occurs during the period from harvest to market. The post harvest handling producedures used in these crops can have a dramatic impact on marketability, quality, shelf-life and thus net profit. Another objective is to evaluate new packing line procedures and field procedures that affect quality, marketability and shelf-life of vegetables. Several traditional studies willb e conducted to develop or refine post-harvest procedures that result in less post-harvest losses and longer shelf-life for products. <P>APPROACH: P. Capscici: Pepper plants from resistant lines will be grown along with susceptible check plants at locations which have previously suffered damage from P. capsici. The experiments will be conducted in a randomized complete block design. Percentage of P. capsici infested plants will be assessed at several points during the growing season. Fruit will be harvested and the productivity of the different lines will be determined statistically. Recommendations can then be made to growers as to the best cultivars to use according to the amount of P. capsici pressure at the growing location. Resistance to the foliar blight, stem blight, and root rot disease will be evaluated separately since they are under independent genetic control. Resistance to foliar blight will be screened for by innoculating seedling leaves with zoospores and incubating in a dew chamber for several days. Stem inoculation will be achieved by accepted methods whereby cotton yarn is tied around the stem and inoculated with zoospores. Root rot resistance will be assessed where seedling roots are inoculated with zoospores and then flooded for two days. Germplasm to be screened will include previously identified resistant and susceptible selections as controls. New selections will primarily include material from the USDA Capsicum germplasm collection. Once new sources of resistance have been found, they will be transferred into commercially acceptable bell pepper lines. The first step will be to transfer the resistance genes into adapted bell pepper germplasm. This has been done in the past by the traditional breeding processes of recurrent selection. This process begins by conducting crosses between resistant and susceptible lines to determine the genetic inheritance of newly discovered resistance sources. Once the genetic inheritance is known, this information will be used to determine the most efficient method of introducing the resistance into elite germplasm. Post Harvest: Studies will be initiated to study packing line arrangements, sizes and components that result in the highest quality and least loss of product. Drop studies on packing lines, size and color sorting equipment, and sanitation steps will be evaluated using accepted post harvest and engineering techniques. Field Production Impacts on Quality and Storage. Experiments will include various levels of fertility and water management as they relate to storage life and quality. Replicated field studies will include the various nutrient and water management treatments which will be harvested and placed under various storage conditions to evaluate shelf life and quality. Time and motion studies for various harvest and packing house operations will be conducted to determine the amount of labor required for various operations on certain vegetable crops. This will allow producers to more accurately predict their labor requirements. The procedures employed by Darrell Mundy (Rhea, et al, 2001) will be the model for these studies.