Field and greenhouse tuberization of six potato cultivars grown From in vitro plantlets

Department of Plant Production, College of Agriculture, King Saud University, Riyadh, Saudi Arabia and Department of Horticulture, Colorado State University, Fort Collins, CO 80523. USANodal cuttings of six potato (Solanum tuberosum) cultivars were used to compare their tuberiza-tion response under field and greenhouse conditions. Cultivars used were: Desiree, Kennebec,"Norgold Russet, Norland, Russet Burbank and Spunta. Murashige and Skoog media was used for subculturing. Plantlets grown in vitro were transplanted into greenhouse benches filled with Metro Mix potting soil. Starter fertilizer was applied. Acclimatization was carried out by 50 % shading and frequent misting. Minitubers were harvesed 12 weeks after trans-planting. Another study was undertaken under field conditions to compare tuber production of the six cultivars from the in vitro produced plantlets. Significant differences occurred between cultivars grown either under field or greenhouse conditions. Cultivars response to treatments were correlated under both conditions. Significant correlation was found between average number of minitubers and average weight of field grown tubers. These studies indicated that the potential for estimating yielding ability of potato under field conditions can be obtained by a small condensed greenhouse trial for mini tuber production