Cycle 2 (2012 Deadline)
Improving yam (Dioscorea spp.) seed systems through production of dormancy-controlled seed tubers in temporary immersion bioreactors
PI: Morufat Balogun (University of Ibadan)
U.S. Partner: Wayne Curtis (The Pennsylvania State University)
Project Dates: August 2013 to September 2014
The production of yams, which are food security and poverty alleviation staples in West Africa, is constrained by scarcity of planting materials and low multiplication rates, which account for up to 63% of production cost. Tuber dormancy also hampers out-of-season production, while uncontrolled sprouting after dormancy causes storage losses. Microtubers produced in test tubes (in vitro) have been proposed as alternative propagules whose dormancy can be exogenously controlled (Balogun, 2005). Although the duration of dormancy of microtubers was shown to be affected by plant growth regulators applied at different growth phases, the tuber production rate remains slow, the low yields are not amenable to farm level production, and small tuber size limits direct transplanting to the field. Use of temporary immersion bioreactors in in vitro cultures has been recognized as a means to improve plant propagation in other crops, and the idea is adaptable to hundreds of species. Temporary immersion facilitates scale-up of propagation of large masses of plant tissue, which is useful because it does not require costly agar, reduces contamination in cultures, and provides a means for sequential manipulation of the nutrient medium at different developmental stages with minimal labor input.
The goal of this project is to identify optimum conditions for production of seed tubers of white yam whose dormancy can be efficiently controlled. This research will aid the optimization of protocols for seed yam production and increase seed supply and quantities consumed at lower expenditure levels. The immediate uses of the research results will be micropropagation of disease-free plantlets, in vitro conservation of plantlets without losses associated with field collections, and in vitro evaluation of yield in transgenic yam. The potential uses of the results include out-of-season production and extension of the storage cycle. The overall development impact is that enhanced yam productivity will help Nigeria to feed her people while also empowering them through trade.
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