Effects of different light exposure regimes on pre-sprouting and yield performance on potato (Solanum tuberosum L.) seed in Central Rift, Kenya

The major problems affecting potato (Solanum tuberosum L.) production in Kenya include timely availability of well-sprouted seed potato tubers. Appropriate techniques of availing well-sprouted potato seed for timely planting for different potato varieties with varied seed dormancy periods is one of the major challenges for yield increase. A study was conducted to determine the effects of different light exposure regimes on pre-sprouting, seed germination and yield performance of potato in Central Rift, Kenya. Three light exposure regimes of 8, 12, and 16 h were evaluated in lighthouse for their effects on breaking dormancy and enhancing pre-sprouting in three potato varieties. The lighthouse experiment was laid on complete randomized design (CRD) with three replicates while field experiment was laid on randomized complete block design (RCBD). Data collected on the number of sprouts, sprout lengths, diameters and colour; emergence rate, plant height, number of tubers per plant, and tuber weight were subjected to analysis of variance (ANOVA) and means were compared using Duncan multiple range test (P<0.05). There were significant differences (P<0.05) in different light exposures on traits. Light exposure regimes significantly increased sprout thickness by 31 to 43% and sprout length by 15 to 39% when compared with those of control treatment. Light exposure of 16 h resulted in the highest percent seed germination and tuber weight by 9.5 and 25%, respectively. This suggests that increasing period of light exposure by using simple fluorescence system in pre-sprouting stores will enhance breaking of potato seed dormancy resulting in increased yields.