Effect of planting bed and foliar application of supplementary organic matter (Humi-ferthi) on mini-tuber production from micro-tubers in two potato cultivars

To study the effect of different planting beds and amount of Humi-ferthi as supplementary organic fertilizer on quantitative and qualitative traits of min-ituber of two potato cultivars، an experiment was carried out under greenhouse conditions in Ardabil، Iran، in 2012. A 2×3×3 factorial experiment was conducted using completely randomized design with three replications. Experimental factors included two potato cultivars (Agria and Savalan)، three planting beds (forest leaf composts of Fandoglo of Ardabil+ perlite، forest leaf composts of Andabil of Khalkhal + perlite، and Mixkaar peat mass + perlite) as second factor and three levels of organic fertilizer of Humi-ferthi consisted; zero (control)، 2‰ and 4‰. Results showed that cultivar effect was significant on mini- tuber weight per plant and plot and concentrations of P، K and Ca nutrients in min-ituber tissue. Effect of organic fertilizer on concentrations of P، K، N and Ca nutrients on mini-tuber tissue was also significant. Cultivars × planting bed interaction effect on mini-tuber number per plant and mini-tuber weight per plot as well as the cultivars × organic fertilizer interaction effect on mini-tuber weight per plot were significant. Mini-tuber weight per plant and plot and concentrations of P، N and Ca nutrients in mini-tuber tissue were significantly influenced by planting bed and organic fertilizer interaction. The highest number of mini-tubers per plant (7. 8 mimi-tubers) was obtained from Agria cultivar in Mixkaar peat mass + perlite. Andabil forest leaf composts with 2‰ of organic fertilizer (Humi-ferthi) had the highest mini-tuber weight per plant (223. 7 g). The highest nitrogen، phosphorus and potassium contenets of mini-tuber were obtained in combination of 2‰ Humi-ferthi + Fandoglo leaf composts. Considering the importance of number of mini-tuber in mini-tubers production stsytem، it is concluded that planting micro-tubers of Agria cultivar in media of leaf composts of Andabil + perlite and application of Hiumi-ferthi (2‰) is suitable and economically reasonable for producing mini tuber. As well as in all of the qualitative characteristics، Miksskar peat mass + perlite were suitable planting bed، which could improve the quality characteristics of both potato cultivars with using 2‰ or 4‰ supplementary organic fertilizer.