Potato is an important food and cash crop in Uzbekistan. Growing and selling potato makes up a big part of income for smallholder farmers in rural areas. But there are many factors that reduce farmers' margins and make potato cultivation less attractive. Potato production in Uzbekistan mainly depends on imported seed potatoes, which are quite expensive for farmers and account for about 50% of the cost of production. The imported seed potatoes cost around 2,400 UZS (slightly over 1 USD at the exchange rate) and more per kg in 2012. Moreover, not many can afford hiring agricultural machinery during the planting season. So many farmers end up using the same seed potatoes for two or more seasons, and often collect much less harvests because of seed-borne diseases accumulated in seed potatoes selected by farmers.
This problem made the CIP regional office in Uzbekistan come up with a cost-effective solution, which is valid for smallholder farmers. To this end, CIP, an international potato research organization, started a project on positive selection of seed potatoes in 2012 in Tashkent Region. Normally, farmers start sorting out potatoes, which are later kept in the cellar, at the end of winter: the largest ones are for sale or personal consumption, while the smallest ones are used as seeds in the next season. This method is deeply flawed and contributes to increasing the spread of diseases. The selection of seed potatoes must be done in the field by choosing the healthiest and most vigorous plants when they are about 25 cm high, and continues until plants close the rows. This selection technique is called "positive selection", as opposed to "negative selection" that involves removing plants showing signs of a disease.
In positive selection, the selected plants are marked with wooden stakes and harvested by hand before the others. Seed potatoes must be kept in the store or cellar separately for the next season. These steps are repeated in the following year. Seed tubers from the selected plants must be always planted in separate fields. This very simple technique helps farmers to ensure continuity of healthy seeds and good yields over subsequent seasons. vWith this in mind, CIP specialists trained a group of farmers in positive selection in May 2012. In fact this training is part of the activities being carried out within the CIP-led global CGIAR Research Program on Roots and Tubers.
Following the training, the farmers selected some seed potatoes using positive selection. These selected tubers were harvested in October 2012 and kept separately from those harvested from the other plants until next season. In early May 2013 these seed potatoes were planted in two separate land plots, one with seeds from positive selection and the other with seeds selected traditionally. This was done to show farmers the difference between their traditional methods and positive selection. In the course of the season, all the plants will be screened using Enzyme-linked immunosorbent assay (ELISA) so as to show farmers the better value of positive selection compared with traditional seed multiplication methods due to the decreased amount of viruses in the selected plants. ELISA is used in, among other things, agriculture to detect potato viruses.
True, it will take some time before positive selection is adopted widely. But this is surely the first step towards greater positive impact on the livelihoods of smallholder farmers in rural areas. It will save farmers money and increase their income. What is more, if potato cultivation gains more appeal, it could contribute to more employment opportunities for young people too.