Effects of Leaf Age, Leaf Area, and Plant Growth Regulators on the Production of Potato (Solanum tuberosum L.) Minitubers Derived from Direct Shoot Cuttings

摘要

The study was carried out to investigate effects of leaf age and area of shoot cuttings, and planting media types on the rapid multiplication of potato seed tubers. Axillary buds and the basal portions of the petiole were buried in a moist medium, containing equal volume of commercial soil and vermiculite and then placed under continuous light and examined for the production of minitubers after 3 weeks. Young and fully expanded leaves on third to seventh node from the top showed significantly highertuberization rate (100%) and bigger minituber size (average 1.51 gode in 'Superior' and 1.25 gode in 'Winter Valley') than the very young or very old and less expanded leaves in the single node cuttings. Defoliated stem with four nodes gave less tuberization and less average minituber weight than the stem with leaf and apex or without apex in both cultivars. Medium containing equal volume of commercial soil and vermiculite was the most effective for both higher tuberization (average 100%) and higherminituber yield (average 1.52 gode in 'Superior' and 1.55 gode in 'Winter Valley'). For the application of plant growth regulators, 6-benzylaminopurine of 10 mg centre dot L~(-1) produced significantly higher percentage of tuberization and bigger minituber size (average 1.35 gode in 'Superior' and 1.31 gode in 'Winter Valley') as compared to 50 mg centre dot L~(-1) kinetin and the untreated control. Thus, minitubers produced by direct cuttings can provide an alternative method for the rapid production of potato seed tubers compared to that produced by conventional minituber production systems.