PRODUCTION OF PRENUCLEAR MINITUBERS OF POTATO WITH FEAT-BASED ARBUSCULAR MYCORRHIZAL FUNGAL INOCULUM

Prenuclear minitubers of potato (Solanum tuberosum L.) are the source material used to produce field-grown seed potatoes, Seed potatoes are in turn planted by commercial growers to produce potatoes for fresh pa cking and processing, Arbuscular mycorrhizae (AM) have been demonstrat ed to increase yield in low-input systems. This study was conducted to determine whether and how a commercial AM inoculum influences prenucl ear minituber production under high-input commercial conditions. A pea t-based medium containing the mycorrhizal fungus Glomus intraradix was tested in a commercial minituber greenhouse production facility. This medium increased yields of the most valuable sizes of prenuclear mini tubers by 84%, and increased total prenuclear minituber yield by 49% w hen compared with conventional peat-vermiculite media under commercial growing conditions. Potato plants grown in this mycorrhizal medium ha d more uniform stolen development, as well as stolons 39% longer than plants grown in the conventional medium. These yield increases and mor phological changes occur in the presence of very low levels of mycorrh izal colonization, and there was no evidence of the enhanced plant P n utrition generally associated with mycorrhizal symbiosis, These effect s may indicate the presence of a hormonally mediated plant response to the mycorrhizae that results in more uniform stolen growth and an inc rease in tuber initiation.