Location: Tropical Crops and Germplasm Research2011 Annual Report
1a. Objectives (from AD-416)
Evaluate tropical/sub-tropical fruit production systems and germplasm for broad agro-environmental adaptation, high yield and productivity, and ability to produce fruits of superior quality. Develop efficient and sustainable monitoring and/or control methods for key pests that limit tropical/subtropical fruit production and quality.
1b. Approach (from AD-416)
Field evaluations for yield and fruit quality traits of selected tropical fruit crop scion and/or rootstock germplasm will be conducted in various agro-environments. Nutrient requirements and utilization efficiency studies will be conducted to optimize nutrient applications. Control strategies for plant pathogens of tropical and subtropical fruit crops will be developed using systemic acquired resistance agents. Strategies to increase pollinators in Annonaceae will be developed. Field evaluation of biological agents for biocontrol of important insect pests of tropical and subtropical fruit crops will be conducted.
3. Progress Report
The following research was conducted: 1) an experiment to evaluate six lychee cultivars for yield and fruit quality traits at two locations in Puerto Rico continued; 2) an experiment to evaluate six atemoya clones for yield and fruit quality traits was completed; 3) an experiment to evaluate 12 dragon fruit (pitahaya) cultivars and lines continued; 4) an experiment to screen mamey sapote germplasm for acid soil tolerance was harvested and biomass production for each accession determined; 5) a greenhouse experiment was established to determine the effect of soil pH and various concentrations of iron on early growth of mangosteen trees; 6) an experiment to evaluate three longan cultivars as rootstocks and in combination with three scions continued with trees producing fruit for the first time; 7) an experiment to evaluate 16 sapodilla cultivars as rootstocks continued; 8) an experiment to study the performance of 12 cacao accessions propagated by grafting and somatic embryogenesis continued; 9) the first year of an experiment to evaluate cultivar FHIA-17, a Sigatoka-tolerant banana, for yield and fruit quality traits was completed. We established an experiment to evaluate nutrient uptake, yield and fruit quality traits of four mamey sapote cultivars grown at two locations in Puerto Rico; a similar experiment with carambola was completed and tissue is being processed for nutrient analyses. Establishment of commercial pheromone of Nitidulids in orchards of atemoya increased yields, and surveys of visitors to atemoya flowers identified pollinators not previously reported in the literature. The first year of a field experiment to determine the effect of induced systemic acquired resistance (SAR) agents on reducing the incidence of the papaya ringspot virus (PRSV) was completed. We gathered evidence showing that protein lures typically used for the detection and monitoring of fruit flies in the genus Anastrepha showed that lures that were a month old outperformed fresh lures, suggesting the lower doses of the lures are more attractive, or, conversely, that higher doses of the lures are repellent. We demonstrated that tall grass barriers, such as rows of sorghum, around an orchard impede migration of the May beetle into these orchards. We identified entomopathogenic nematodes that were effective in controlling the root weevil of Diaprepes abbreviatus but not against Phyllophoga vandinei. We surveyed populations of lychee scale in orchards. Parasitoids and predators were too low in number to successfully rear and assay their effectiveness in the laboratory. We demonstrated that abundance of winged aphids, the vector of papaya ringspot virus, is cyclical in Puerto Rico, with population peaks occurring more or less every two months. The results from these experiments help to fill knowledge gaps on cropping management and production systems for tropical/subtropical fruit crops.