A field experiment was carried out to evaluate True Potato Seed (TPS) production and its relative economic return as influenced by supplemental nitrogen (N) at a range of 0-250 kg ha-1 and planting density at a range of 8-16 haulms m-2 in potato mother plants (Solanum tuberosum L.) using a cross of MF-II ( female ) and TPS-67 ( male ). The single effect of supplemental N application and planting density on the yield of berries and TPS was significant. Number of berries plant-1, mean berry weight, number of TPS berry-1 and yield of TPS showed maximum values when 0-150 kg N ha-1 was applied, but the values decreased thereafter as supplemental N application increased, irrespective of the size of the harvested berries. Although only the weight of 100-TPS showed a maximum value at 250 kg N ha-1 application, the value was similar to that at 200 kg N ha-1 application. Mean berry weight, number of seeds berry-1 and weight of 100-TPS showed the maximum values at the lowest (8 haulms m-2) planting density and the values decreased thereafter as the planting density increased, irrespective of the size of harvested berries. A positive effect of higher planting density was detected only in the number of berries plant-1 and yield of TPS. The combination effect of supplemental N application and planting density on the yield of berries and TPS was also significant. Although the total yield of TPS was the highest at the combination of 150 N kg ha-1 and 16 stems m-2, the yield of large size TPS, which is regarded as high quality TPS, was the highest at the combination of 200 N kg ha-1 and 12 stems m-2. This was also true for the other characteristics of harvested TPS under different supplemental N applications and planting densities; i.e., number of berries plant-1, number of TPS berry-1 and weight of 100-TPS showed the maximum values at the combinations of 0-150 N kg ha-1 and 8-16 stems m-2 or 200 kg N ha-1 and 8 stems m-2, but not at 200 N kg ha-1 and 12 stems m-2. The benefit cost ratio, which was estimated from total cost of production and gross return also showed that the combination of 200 kg N ha-1 and 12 stems m-2 were the optimal growth conditions to harvest high quality TPS from the potato mother plants.
Roy, T. S., Takashi Nishizawa, Ali, M. H.
Faculty of Agriculture, Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka-1207, Bangladesh.
Asian Journal of Plant Sciences, 2008, Vol. 7, No. 1, pp. 73-78
http://www.ansinet.org/ajps
Filed under: Fertilizer, Research, TPS
