Influence of plant spacing on seed and ware tuber production of potato (Solanum tuberosum L.) cultivars grown in Eastern Ethiopia

Abstract

Plant spacing is an important agronomic consideration in the production of potato (Solanum tuberosum L.). However, the spacing of 30 cm between seed tubers and 75 cm between rows has been invariably used across all parts of Ethiopia. The practice of using this spacing across the country regardless of the variety to be cultivated, the purpose of production (seed potato or ware potato), agro-ecology, etc. may lead to lower tuber yields. To elucidate this problem and the effect of plant spacing on the productivity of different potato varieties, field experiments were conducted in Hirna and Haramaya districts in the Hararghe Zones of Eastern Ethiopia. The treatments consisted of five plant spacing and four potato cultivars. The experiment at each location was laid out as a completely randomized block design in a factorial arrangement and replicated three times per treatment. Analysis of total, marketable and unmarketable tuber number  per  unit  area  obtained  indicated that  the  effect  of  cultivar  and  spacing  highly significantly (p<0.01) influenced. The cultivar and plant spacing highly significant (p<0.01) affect tubers size distribution. Total tuber yield responded highly significantly (p<0.01) to the effects of cultivar and spacing. Results of the experiment revealed that keeping intra-row spacing of 25 cm, the inter-row spacing of 50 cm and 60 cm produced total yield of potato tubers of 31.24 and 30.97 tone ha-1 respectively, i.e. more than 41% the yield of commonly used spacing of 75 cm x 30 cm. The highest number of seed-sized tubers (40-75 g) was obtained at high planting density, i.e. 50 cm x 25 cm and 60 cm x 25 cm. Since spacing 50 cm x 25 cm requires more planting material and also makes inter-cultivation practices more difficult, the spacing of 60 cm x 25 cm was recommended for maximizing production of both seed and ware potatoes.