The effect of altitude of seed production on potato seed vigour
Seed potatoes, variety Anett, were raised at three different altitudes: Thika (1440 m), Kabete (1800 m) and Limuru (2225 m) and at each site in soil transported from the other sites in large tins; in two seasons. The seed raised at all sites was planted the following season at Kabete for ware production. In the first experiment, Limuru site yielded the highest number of tubers and fresh weight of tubers, followed by Thika site despite the fact that plants at Thika had shown a more vigorous vegetative growth than Limuru plants. In the second experiment, Thika site yielded the lowest number of tubers and fresh weight of tubers per plant. Limuru site yielded the largest number of tubers but Kabete yielded the highest fresh weight of tubers per plant .. In storage, seed tubers from Thika were the first to sprout, yet their sprout length and number of sprouts were the least. Limuru seeds sprouted last and had the highest sprout number and length, but these were not significantly different from those of Kabete seed. In the field, plants from Limuru seed were the first to emerge, followed closely by plants from Kabete seed. Plants from Thika seed were the last to emerge and showed a poorer vegetative growth than plants from Limuru and Kabete seeds. The plants from Thika seed senesced earlier than those from Limuru and Kabete seeds. In the first experiment, the final ware yield was highest in plants descended from Limuru seed and lowest in plants from Thika seed. In the second experiment, plants from Limuru seed yielded the highest number of tubers, but plants from Kabete seed yielded the highest fresh weight of tubers. The lowest yield was obtained from plants descended from Thika seed. It was concluded that in Kenya seed potatoes perform better if raised in the medium and high altitudes above 1400 m.