Loretta J. Mikitzel1
(Partner: Mr. Robert Watson, Salmon River Farm)
Abstract: This study was initiated to determine if high generation seed potato producers could prepare plantlets for transplanting on their farm and to determine if planting trays (cell packs versus pro-trays) have an effect on plant growth and yield. Russet Burbank and Superior plantlets were transplanted directly from phytotrays into a commercial screenhouse on May 25, 1999 or hardened off in cell packs or pro-trays in a glassed-in porch for three weeks then transplanted on June 15, 1999. Additional plantlets were transplanted directly from phytotrays on June 15, 1999. For Russet Burbank and Superior, plantlets grown in the screenhouse since May 25, 1999 produced the highest yield of tubers and 73% of the tuber yield was accounted for by minitubers weighing more than 40 grams each. For both cultivars, increased yields were due to more tubers being set by the May 25 plants, not an increase in average size of the tubers. Performance of plants hardened off in the cell packs was similar to that of plants hardened off in pro-trays and both produced one-half the yield of the May 25 plants. Hardening off the plants for three weeks lowered minituber yields probably due to recovery time needed for the plants to overcome transplanting shock. Plantlets placed in the screenhouse on June 15 produced the lowest yields and fewest tubers. These plants were growing for only 81 days, compared to 102 days for the other treatments. Planting tray had no effect on plant performance. The length of time potato plantlets grew uninterrupted in the screenhouse had an impact on yield.
1Potato and Horticulture Branch, NBDARD, Wicklow, NB E7L 3S4