The influence of different media on the rooting abiligy of Potato stem cuttings.

The best medium for the formation of a desirable root system by potato stem cuttings was determined in green-house using appropriate cuttings from three Alemaya selections (AL-562, AL-517 and AL-204) and variety Anita rooted in nine different locally available media. The basic ingredients of the media were sawdust, sand, soil and manure. There were 20 cuttings per medium per selection. Rooting ability of cuttings in each medium was evaluated on every other day starting from the 14th day to the 20th day from the time of insertion. The result indicated that all cuttings formed roots in all media within 16 days with the exception of selection AL-517 in sawdust, and AL-204 in soil and a 2:1combination of sawdust and manure. When characters such as number and lengths of roots per cutting, and number of branch roots per adventitious root were considered, either sand or sand mixture medium with the exception of a 3:2:1combination of sand, soil and manure respectively, gave better results. The formation of roots was comparatively poorer in sawdust and in a mixture of sawdust media. It was also observed that the formation of roots apparently varied among potato types. The Anita variety showed the development of more roots almost in all media considered, while selection AL-517 formed a relatively less number of roots as compared to the others. Potato (Solarium tuberosum L.) is conventionally propagated by tubers. This method of propagation involves transportation and storage problems, high seed cost, and low multiplication rate. These basic shortcomings make the method inefficient in the attempt to multiply and distribute to fanners enough seed tubers of improved potato clones in a relatively short period of time. Hence, an adoption of rapid multiplication systems becomes indispensable. One of the rapid multiplication systems is the use of stem cuttings (6). Using this method, about 180 kg of potatoes can be produced from 1 kg of potatoes for the first generation of basic seed programme which is considered significant when compared to harvesting of about 10 kg of potatoes from 1 kg of potatoes in the traditional method (6). The type and nature of cuttings seem to have an influence on root formation. Good results are obtained from cuttings with slender, flexible and well branched roots than cuttings with coarse, brittle and unbranched roots (8). The development of roots and the rooting ability in general are influenced by types of media (5, 8). Cuttings produce good roots in a medium which provides good anchorage, contains enough moisture and air around the cuttings and has good drainage system (5). Among the media used for rooting stem cuttings and other organs of plants are soil, sand, peat, moss, perilite, pumice (5), shreded sphagnum (4), vermiculite (2, 11), and sawdust (1). Sand is the most widely used rooting medium for cuttings. However, it has a tendency to produce coarse brittle and sparsely branched roots which are considered undesirable (8). Hence, the use of mixtures of the above mentioned media instead of anyone of them alone is recommendable for the development of desirable rootings (5, 8, 11). The primary objective of this study was to select a medium that best favors the formation of desirable root systems for potato stem cuttings.