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United States Department of Agriculture

Agricultural Research Service


Location: Tropical Crops and Germplasm Research

2012 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 12 dragon fruit (pitahaya) cultivars and lines continued; 3) an experiment to screen mamey sapote germplasm for acid soil tolerance was harvested and biomass production for each accession determined; second year planting was established; 4) a greenhouse experiment to determine the effect of soil pH and various concentrations of iron on early growth of mangosteen trees was completed; 5) an experiment to evaluate three longan cultivars as rootstocks and in combination with three scions continued; 6) an experiment to evaluate 16 sapodilla cultivars as rootstocks continued; 7) an experiment to study the performance of 12 cacao accessions propagated by grafting and somatic embryogenesis continued; 8) the second year of an experiment to evaluate cultivar FHIA-17, a Sigatoka-tolerant banana, for yield and fruit quality traits was completed; 9) an experiment to evaluate cultivar FHIA-21, a Sigatoka-tolerant plantain, for yield and fruit quality traits was established at two locations; 10) trials of commercial pheromones of Nitidulids in orchards of atemoya demonstrated that at least two potential pollinators of atemoya are attracted in a dose dependant manner when lures are used in combination; 12) continued to demonstrate that tall grass barriers, such as rows of sorghum, around an orchard impede migration of the May beetle into these orchards; 13) conducted an analysis of arthropods intercepted by regulatory agencies over three years (2006-2009), indicating where these interceptions most frequently occur, origin of the interceptions, and identity of the arthropods; 14) assessed that the establishment of a fruit fly-free zone is feasible in Puerto Rico, based on the fact that natural areas appear to be significant barriers to the dispersal of fruit flies. An experiment to evaluate nutrient uptake, yield and fruit quality traits of four mamey sapote cultivars grown at two locations in Puerto Rico was established; a similar experiment with four rambutan cultivars was also established. The second 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 and results are being analyzed. Continued to assay lures used to monitor and detect economically important fruit fly species. Current trapping methods leave a lot to be desired with respect to efficiency. Nevertheless, better options do not exist. Our work highlights methods that optimize the efficiency of the traps, including trap placement and bait dosage. These methods have been communicated to regulatory agencies charged with monitoring/detecting invasive fruit fly species. The results from these experiments help to fill the knowledge gaps on cropping management systems for tropical/subtropical fruit crops.

4. Accomplishments
1. The demand for tropical fruits has increased significantly during the last decade as consumers seek healthy and more diverse food products. There is a lack of formal experimentation to determine yield performance and fruit quality traits of mamey sapote (Pouteria sapota) cultivars. Six mamey sapote cultivars (Copan, Magana, Mayapan, Pace, Pantin, Tazumal) grown on Ultisol and Oxisol soils were evaluated for 5 years at Corozal and Isabela, PR, respectively. There was a significant difference in the number and weight of fruit per hectare between locations, averaging 25,929 fruit/ha and 16,527 kg/ha at Corozal and 17,887 fruit/ha and 11,920 kg/ha at Isabela. ‘Tazumal’ had the highest 5-year mean number and weight of fruit per hectare, but fruit of this cultivar was very small and contained several seeds, which could reduce its marketability. At Corozal, cultivars Tazumal and Magana had significantly higher fruit yield per hectare than the rest of the cultivars, whereas ‘Magana’, ‘Tazumal’, and ‘Pantin’ had the highest fruit yield at Isabela. At both locations, ‘Pantin’ had relatively high yield, above-average soluble solids concentration values, and adequate fruit size and weight for domestic and export markets (650–900 g), making this cultivar suitable for planting at various agroenvironments typical of the humid tropics. This study provides for the first time valuable information to growers and Extension specialists on yield, fruit quality traits and adaptability of rambutan cultivars grown in various agroenvironments.

Review Publications
Jenkins, D.A., Kendra, P.E., Epsky, N.D., Montgomery, W.S., Heath, R.R., Jenkins, D.M., Goenaga, R.J. 2012. Antennal responses of West Indian and Caribbean fruit flies (Diptera: Tephritidae) to ammonium bicarbonate and putrescine lures. Florida Entomologist. 95(1):28-34.

Goenaga, R.J., Jenkins, D.A. 2012. Yield and Fruit Quality Traits of Mamey Sapote Cultivars Grown at two Locations in Puerto Rico. HortTechnology. 22:263-267.

Osuna-Garcia, J.A., Doyon, G., Salazar-Garcia, S., Goenaga, R.J., Gonzalez-Duran, I. 2012. Relationship between skin color and some fruit quality characteristics of 'Hass' avocado for the export market. Journal of Agriculture of the University of Puerto Rico. 95(1-2):15-23.

Garcia, J., Jenkins, D.A., Chavarria, J.A., Shapiro Ilan, D.I., Goenaga, R.J. 2011. Interactions of a Rhabditis sp. on the virulence of Heterorhabditis and Steinernema in Puerto Rico. Florida Entomologist. 94(3):704-705.

Last Modified: 06/24/2017
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