Recipient Organization
COLLEGE OF MICRONESIA
PO BOX 1179
KOLONIA POHNPEI,FM 96941
Performing Department
COLLEGE ADMINISTRATION
Non Technical Summary
Project SummarySweet potato (Ipomoea Lam var. batatas) is underutilized crop in the Marshall Islands and other parts of the world. Its potential benefit to food security is very obvious especially to small and vulnerable communities like the Marshall Islands (RMI). Sweet potato is an easy to grow crop that can withstand extreme weather and soil conditions. It requires only minimal management effort and seldom being attack by pest and diseases. Aside from its tubers being utilized as food source, the young leaves can also be utilized as green vegetable to make soup, or fried like tempura and even used as salad. Lots of health benefits associated with sweet potato like lowering blood sugar and high blood pressure so it is very beneficial to prevent or reverse the effect on non-communicable diseases (NCDs). It is a good source of vitamin A, phosphorous, calcium and fair amount of iron, thiamin and some other nutrients and dietary fibers that are very important in maintaining good health. Most varieties of sweet potatoes are ready for harvest in about 4-6 months. Depending on the planting schedule, number of plants, and water availability, sweet potatoes can be available throughout all the seasons of the year. Hence, sweet potato will be well suited as alternative crop for breadfruits, cooking bananas and some taro varieties. The project aims to investigate and compare the growth performance of two locally available varieties of sweet potatoes. In addition with the two varieties, a third important variety of sweet potato will be introduced for field trial. This sweet potato will be sourced from a salt tolerant breeding line (new mutant variety) developed by the International Atomic Energy Agency-Secretariat of the South Pacific (IAEA-SPC) for the people of the Marshall Islands to utilize. The growth performance of three sweet potato varieties will be investigated using different soil amendments, compost formulations and fertilizer recommended rates. The experimental design to be used will be the Randomized Complete Block Design. Growth performance parameters (yield, biological efficiency conversion, pests and diseases incidence) and salt tolerance (percent mortality, growth reduction) will be measured, compared and analyzed using Analysis of Variance (ANOVA) and treatment means will be evaluated using Duncan's Multiple Range Test (DMRT) at 5% level of significance. The result of this study will be disseminated in different forms of extension materials and conducted activities that will promote sweet potatoes production for food security in the RMI region.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
GoalTo determine the production capability of sweet potato for food securityObjectivesTo collect and propagate three sweet potato varieties in preparation for experimentationTo compare the growth performance and pests/diseases responses of three different varieties (two local varieties, one exotic mutant variety from IAEA-SPC, Fiji) on different locations, seasons, soil condition and amendmentsTo do screening test for drought and salt tolerance of new mutant variety of sweet potato together with the two local varieties for reference.
Project Methods
Methodology and Research DesignObjective 1. To collect and propagate three sweet potato varieties in preparation for experimentationAll the varieties to be used in this experimentation will be assessed carefully to ensure a disease free propagules. There are two common varieties of sweet potatoes in the RMI region namely: white-fleshed and purple-fleshed varieties. White-fleshed sweet potato has green leaves and purple fleshed ones have green and purple leaves (top young leaves). Both are commonly grown in the both in main and outer islands of RMI region. The third variety will be sourced from a salt tolerant breeding line (new mutant variety) developed by the International Atomic Energy Agency-Secretariat of the South Pacific (IAEA-SPC) for the people of the Marshall Islands to utilize. The seedlings will be propagated at the Agricultural Experimental Station of the College of the Marshall Islands Cooperative Research and Extension (CMI-CRE) facility, Arrak Campus, Majuro Atoll. The propagules to be used as starter will be the sprouts from roots of previous crop or vine tip cuttings from healthy plants of 25 cm long. The vine cuttings can stored in a cool shaded place, soaked in water for days prior to planting. This process will induce rooting. There will be 200 seedlings for each variety to start on the first year. The seedlings will be planted in a one-liter containers and will be transferred into a two-liter containers after before transplanting in the field. This will take for about 3-4 weeks each time. The transplanted sweet potato plants will stay in the demonstration garden for about 4-6 months before harvest. Harvested tubers and cuttings will be used again to produce more seedlings and repeat the process. All necessary daily chores like watering, weeding, fertilization, sanitation, checking for incidence of pest and diseases will be done accordingly. Experimentation and distribution to stakeholders will be done on year two.Objective 2. To compare the growth performance, and pests/diseases responses of three varieties will be compared and tested using different soil and compost formulations in four different locations on Majuro and other participating Islands.Compost preparation and fertilizer application. Compost preparation could take for 4-10 weeks with the help of starters. Starters could be anything like old compost and copra cake added with small amount of sugar or coconut water. For green manure plants, Gliricidia leaves and stems, (size of about one inch in diameter) will be chopped using a machete or shredder machine and set aside. The same procedure will be used for Vigna marina. On the other hand, seaweeds debris will be collected along the shoreline of Majuro and set aside. Coconut husk will be chopped into smaller pieces and chipped. The compost materials will be mixed in the same proportion (1:1:1:1:1). Wire mesh bins with a height of three feet and two feet in diameter will be set up in preparation for the composting process. Wire mesh would allow proper aeration without the need of turning or remixing it repeatedly. For treatments with NPK (16-16-16), the full recommended rate (RR) would be 20 g per plant and 10g for ½ RR (Comia, 2011). Fertilizer will be applied as basal on the 14th after transplanting. The remaining amount of fertilizer will be applied every 30 days and skip for month before harvest.Experimental Design. The experimental design to be used for this project will be Randomized Complete Block Design (RCBD) with three replications for each variety and treatment. Each replicate will be composed of 16 seedlings/plants per 1'x3'x9' raised bed. The treatments to be used are as follows:T1 = topsoil (control),T2 = Topsoil + chicken manure, (3:1)T3 = Topsoil + copra cake (3:1)T4 = Topsoil + compost-seaweed debris, coconut husk, Gliricidia and Vigna (3:2)T5 = Topsoil + NPK at full recommended rateT6 = T4+ NPK at full recommended rate (20 g/2-gallon pot)T7 = T4 + NPK at ½ recommended rate (10g/2-gallon pot)Growing the test plants. In a raised beds (1'x3'x9'), the soil and compost will be mixed together according to the formulations and let it stay for 14 days to properly mix and connect the soil with the compost and let the biological processes take place. The transplanted seedlings will be watered twice a day on the first 14 days until the plants adapted to the new environment. Once the plant roots connected to the soil, on the 14th day, fertilizer will be applied for T5, T6 and T7. Daily chores like watering, weeding, checking for any abnormalities, pest and diseases will be done accordingly.Data collection and analysis. The test plants will be harvested six months after planting. Biological Efficiency Conversion (BEC) will be determined. This process can be done by weighing tubers (yield) divided by the mass plant leaves and vines combined. Disease and insect pest incidence will also be noted and recorded accordingly. The gathered data will be analyzed using Analysis of Variance (ANOVA) and Duncan's Multiple Range Test (DMRT) at 5% level of significance.Objective 3. To do screening test for drought and salt tolerance of new mutant variety of sweet potato together with the two local varieties for reference.The source of mutant varieties of sweet potatoes will be coming from the nearest IAEA Regional Office partner- SPC in Fiji. The plantlets can easily be transported through air transport that would only take 8 hours. This will ensure less mechanical damage or stress to the transported plants. Securing quarantine documentation procedures will be implemented. The plants will be taken care of in the nursery facilities of CMI AES. The plantlets will be transplanted in an appropriate containers and garden soils. Fertilization and daily nursery chores will be done accordingly to ensure healthy seedlings before coming out to the fields. Due to a lot of variability in the fields, the testing for salt tolerance will be done in the nursery areas. The plants to be tested will be placed in 2-L pots/containers. Each container will have the same soil mixture. The exposure to salinity will be done 21 days after the plants were being placed in the container. The treatments will be composed of 0mM, 60mM, 120mM, 180mM and 240mM of salt concentrations. Salinity exposures will be done in 14 days of watering twice a day (9:00 AM and 4:00PM) Percent mortality and growth reduction in comparison with control will be measured after 14 days of exposure. The same protocols will be applied to the two local sweet potato varieties. All treatments will be distributed in 3 replications (20 pots per replicate) using Randomized Complete Block Design. Data will be analyzed using Analysis of Variance and treatment means will be evaluated using the Duncan's Multiple Test Range (DMRT) at 5% level of significance.