Management and rationalised fertilisation of improved commercial production of potato mini-tubers

Abstract

Potato (Solanum tuberosum L.) is an important income earner and food security crop for many communities in sub-Saharan Africa (SSA). In Zimbabwe, mini-tubers are the commonly preferred as planting material, owing to their production under disease-free conditions.  The objective of this study was to explore the effects of plant density, frequency of hilling and fertiliser regime, on commercial production of potato mini-tubers. A temperature-controlled greenhouse study was conducted at the Kutsaga Research Station in Zimbabwe; using Diamond potato variety. Treatments included plant density (375, 200 and 100 plants m-2), hilling (4 hilling intervals) and fertiliser regime (2 fertiliser regimes: 1 = supplemented with sulphate of potash; and 2 = supplement ammonium nitrate). The treatments were laid out in a completely randomised design, in a split-spilt plot arrangement; and set up repeated four times. Disease-free 28-day old potato plantlets were obtained from a tissue culture facility at Kutsaga Research Station, and planted in pots filled with Kutsaga soilless Growmixultra growth media. Plant density had a significant (P<0.05) effect on the mini-tuber size, with the highest plant density (375 plants m-2) having the most mini-tubers with sizes < 20 mm. Frequency of hilling only affected mini-tuber size, but not number of mini-tubers produced. Of the two fertiliser application regimes used, fertiliser regime 1 (High C, AN and SOP) had a significant effect on the survival of the potato plantlets and on the size of the mini-tubers. In a nutshell, in order to maximum mini-tuber production, a plantlet population density of 100 plants m-2, with weekly intervals of hilling under fertiliser regime 1, should be maintained to obtain the most viable commercial treatment combination.