An in vitro repository for clonal kiwifruit

An in vitro repository of kiwifruit genotypes comprising both advanced selections and representatives of the genetic diversity within the Plant & Food Research Actinidia collection has been established. The goal is to maintain in vitro tissue in cool storage as a back-up to field and greenhouse collections. This work complements Plant & Food Research's kiwifruit breeding programme where there is a strong focus on developing novel lines including breeding for Pseudomonas syringae pv. actinidiae (Psa) resistance. Kiwifruit is only recently domesticated and the Plant & Food Research germplasm collection includes representatives of the wide genetic diversity seen within the genus. Considerable variation is observed between genotypes in terms of their responses to in vitro culture. While some genotypes grow vigorously in culture, others show poor performance, including tissue collapse, excessive callus development, poor rooting or slow multiplication rates. Some genotypes appear recalcitrant. Over 1000 genotypes have been initiated into in vitro culture with about a third now in cool storage. Genotypes from the two main species A. chinensis, and A. deliciosa have been cool stored for 16 months without loss of vigour following removal from cool storage.