Abstract
Four factors (shade, photoperiod extension, age of mother plant, and mother-plant origin) relating to mother-plant management were studied at a tropical site. Mother plants were mostly grown from whole tubers from cool conditions. Seedlings from true potato seed were also used as mother plants in one experiment. A 25% reduction of irradiance induced most branching per mother plant, and longer internodes compared to the control resulting in more effective rooting of stem cuttings. Denser shade reduced branching and rooting. Photoperiod extension with incandescent bulbs was effective in delaying tuber initiation of rooted cuttings, more so at cooler nights (<16°C). Mother-plant age, at the time cuttings were taken, showed no consistent effect on yield potential; those from 30 to 60 days at the time of cutting were all equally induced to tuberize. There were no significant differences between yields from rooted cuttings from mother plants derived from tubers produced either under cool or warm conditions. This is encouraging for potato production in the lowland tropics since it obviates dependence on cool-produced tubers as planting materials.
