Performance of Irish potato varieties under aeroponic conditions in Rwanda.

Productivity of Irish potato (Solanum tuberosum) is constrained primarily by use of low quality seeds in Rwanda. Many field multiplication generations of vegetatively propagated basic seed result in build-up of seed-borne diseases and subsequent dissemination to new fields. Using soil-less media is an alternative to reduce soil borne disease infections in production of vegetatively propagated planting materials. The objective of this study was to determine the adaptability and optimum plant density of potato varieties under aeroponics production system. Two commercial potato varieties (Kinigi and Kigega) were evaluated in an aeroponics greenhouse at 14, 17 and 21 plants per m2 using a split-plot design with four replications at RAB-Musanze station in 2010/2011. Plant densities were assigned to main-plots and varieties were in the subplots. Nitrogen, P, P, Ca, Mg and other micronutrients were supplied to plants by way of a mist nebulizer in an enclosed environment. Analyses of variance showed highly significant (p<0.01) differences between the two varieties for plant height, number of nodes at nine and eleven weeks after transplanting, days to maturity and tubers per plant. Plant density and variety × density interaction effects were not significant (p.0.05) for any of these parameters. Plants in Kinigi variety were about 50% taller at 3, 5, 7 and 9 weeks after transplanting; developed 2.5 more nodes per plant, matured 49 days earlier, and produced 29 more mini-tubers than Kigega. The data showed that (i) Kinigi variety was more adapted and productive in the aeroponics environment than Kigega. (ii) plant population density had no significant influence on productivity of the two varieties in the system, and (iii) response under aeroponics conditions is cultivar dependent in potato and requires testing more varieties to select the most adapted for production in the system.