Recipient Organization
UNIV OF THE VIRGIN ISLANDS
(N/A)
ST. CROIX,VI 00850
Performing Department
Agricultural Experiment Station
Non Technical Summary
A recently concluded Specialty Block Grant supported work at the University of the Virgin Islands to evaluate twenty-five Pitaya varieties for production potential in the US Virgin Islands. Six varieties have been selected based on production, flavor and color. These include three pink, two red and one white fleshed varieties. Trellis system were also evaluated in the US Virgin Islands to support Pitaya growth. However, the plants grown in the calcareous soils on campus appeared nutrient deficient for iron after two years, even when supplemental chelated iron was applied. Containerized Pitaya production has been observed in southern Florida and Louisiana, where flooding and extended ground supersaturation occurs. We wish to expand on this large container cultivation to examine its potential in the USVI to overcome the nutrient stress observed from growth in calcareous USVI soils. This proposal will expand on the results from the previous projects and utilize the six best varieties in container growing systems. We also will evaluate night interuption to expand the fruiting season by incorporation a two hour lighted break of the night. These systems would be applicable throughout the USVI, Caribbean and Guam where calcareous soils occur. The overall objective is to enhance Pitaya production through the use of containerized growth and night interruption and compare it to in-gound standard cultivation system.
Animal Health Component
80%
Research Effort Categories
Basic
0%
Applied
80%
Developmental
20%
Goals / Objectives
Evaluate Pitaya production potential in 25 gallon versus 45 gallon container as an alternative to in-ground production in high pH calcareous soils;Determine density planting each container can productively supportInvestigate night interuption to extend the Pitaya production season
Project Methods
1 Evaluate production potential in 25 and 45 gallon containers versus in ground growth in calcareous soils. These two container sizes are readily available in the USVI. A four-foot post will be centered in the container and a 1:1:1 mixture of soil, compost and peat based growing medium added to each container. This incorporates the local soil into a modified growing mixture with greater nutrient holding capacity. This utilizes locally available substrates for the growing/potting mix. Drip irrigation will be applied to each contain using spaghetti tubing. Larger containers will have two emitters and smaller container one. This will allow equalized proportions of water to each container based on volume. Fertigation will be utilized through the drip irrigation system. Rebar will be attached to the top of the post and ¾"pvc run from both sides of the post to support the developing branched stems. The pvc will run between containers connecting to the rebar as a trellis.2 To evaluate planting density in each size container, one or two rooted Pitaya cuttings will be planted in the container and trained to grow up to the supporting post. This will determine the number of plants each container can support and develop productive marketable sized fruit. It also will determine the influence of the container size on pitaya growth, flowering and production. Each post will be wrapped with burlap for the aerial roots to adhere to as they climb. Data will be collected on length of time to reach the top of the post, number of branches and floral induction, number of harvests/year, fruit number, fruit size and weight.3 To evaluate extending the pitaya production season a night break will be used as described by Jiang et al (2016). A string of LED lights will be placed in the trellis system. A two-hour break during the dark period, as outlined by Jiang et al (2016), This night interruption should be perceived by the Pitaya plant as two short nights. The break in the night darkness will occur from 10 pm to midnight, starting March 1st and continue to May 1st. This night interruption will also be employed in the fall starting September 1st to November 1st. After May 1st, the day-length naturally promotes floral development in Pitaya. Data will be collected on bud initiation, number of buds and floral development. Production of the night interrupted plants will be compared with control plants.Jiang, Y L, Y.Y. Liao, M T Lin, W J Yang. 2016. Bud development in response to night-breaking treatment in the noninductive period in red Pitaya (Hylocereus sp). HortSci. 51(6):690-696.