The potato in Georgia
Potato is an important crop in Georgia, with approximately 25,000 ha under production, and annual per capita consumption of almost 55 kg (5). Nearly all potato is consumed fresh, and Georgians consider the crop as their “second bread.” Despite potato’s importance in the diet and culture, yields remain low: at roughly 12 t/ha, the national average is far below yields of 40 t/ha or more found in many Northern European countries. Research has demonstrated that with current varieties, attainable yields (on experiment stations and by best high-input farmers) are 25–30 t/ha (3,12). The proposed project will contribute to reduce this large gap between actual and attainable yields.
Tubers serve as the planting material, or seed, of the potato. The poor quality of seed potato is one of the main causes of the low productivity and reduced profitability of Georgia’s potato crop (3,13). As a vegetatively propagated crop, seed potato accumulates pests and pathogens— particularly viruses—over successive seasons of cultivation. This leads to a reduction in yield capacity and/or quality of the product, a phenomenon referred to as Potato Seed Degeneration (PSD) (18). In response to the problem of PSD, seed certification systems in the United States and Europe were developed in the early part of the 20th century. These systems have been highly successful, making high-quality seed readily available to farmers and virtually eliminating PSD in high-income countries. Many efforts to establish certified seed systems for potato in low-income economies, however, have had little success, and most potato farmers in these areas source seed from the informal seed system (e.g., produced on-farm, acquired from neighbors or local markets). Such seed can often be highly degenerated and cause major reductions in productivity.
Currently, about 70% of potato seed in Georgia is self-saved (as part of ware production), produced on-farm primarily by small farmers who are unaware of practices to maintain seed quality (e.g., proper storage). Most of this seed is severely affected by PSD. The portion of seed that is purchased from vendors comes also from ware tubers saved as seed and sold without certification or proper bagging and labeling. Farmers routinely do not use on-farm practices aimed at maintaining seed quality, seed treatment, and seed selection. Nor have they had systematic, formal access to training that would enable them to properly manage their potato harvests. Access to imported seed is limited in Georgia, and such seed is very expensive due to the high relative value of the Euro currency. Seed multiplied from imported seed costs 2–3 GEL/kg, whereas seed from local sources costs 0.5–0.8 GEL/kg. That the quality of imported seed is not guaranteed is another issue; for example, seed quality is sometimes greatly diminished by poor transport conditions. In addition, seed imported from Europe is of varieties that generally lack resistance to pathogens causing PSD, principally the two most yield-reducing viruses, potato virus Y and potato leafroll virus. All of these factors have caused the majority of the seed potato planted in Georgia to be highly affected by PSD.