Potato seed from meristem plants using EVIKA multiplication methods.

A technique developed at the Department of Plant Biotechnology EVIKA of the Estonian Research Institute of Agriculture to multiply disease-free potato seed tubers involves growing plantlets in vitro in plastic rolls on peat before transplanting them to the field. The effects of the method of multiplication, variety, and experimental year on tuber yield were investigated. Plants cultured in vitro from micro-plants were compared with plants grown from tip- and stem-cuttings, and truncated plants that had served as a source of the mentioned cuttings. Two late-maturing potato varieties, Ants and Vigri, were used. The multiplication method, variety, and environmental factors significantly affected the number of tubers per plant and average weight of a tuber. Whereas plants cultured in vitro consistently produced substantially greater numbers of tubers and they were the right size to serve as seed tubers, plants from tip- and stem-cuttings produced fewer tubers and the size of full-grown tubers was too large for seed-production. Truncated plants fell between the two. For seed-potato growing perspectives, the plants from in vitro and truncated plants are the most applicable. Growing tip-and stem-cuttings, the shorter growth period to achieve suitable-sized seed tubers should be adapted. Differences between multiplication methods were smaller in the case of Vigri, which tends to produce more shoots. It is concluded that multiplication methods that result in more shoots per plant also lead to more and smaller tubers. Environmental conditions affected both the number and weight: the dry year, when conditions for growth were adverse, reduced the effect of other factors on the number of tubers whereas near-optimal growth conditions intensified the effect of those factors on tuber weight. [ABSTRACT FROM AUTHOR]