2017 ASHS Annual Conference

Melons (Cucumis melo L.) are potentially a high value crop for New England, but production is limited by cool soil temperatures in spring and sudden wilt. Sudden wilt, characterized by rapid wilting of vines as fruit near maturity, reduces fruit quality and yield. Use of early varieties, raised beds, black plastic mulch and rowcovers have increased early melon yields, but has not reduced the incidence of sudden wilt. One promising solution is grafting melons to an interspecific hybrid squash rootstock [Cucurbita maxima Duchesne x Cucurbita moschata Duchesne], shown to exhibit tolerance to abiotic stress and soil-borne diseases. In the present study we evaluated the performance of grafted and non-grafted plants of ‘Halona’ melon, comparing three transplanting times, two early (12 May and 21 May) and a standard schedule (1 June), in plots at the Kingman Research Farm in Madbury, NH. Season extension cultural methods were black plastic mulch on raised beds and wide floating rowcovers. The rootstock was NH1320, previously demonstrated as a highly compatible rootstock for melon. Early growth and flowering of non-grafted plants exceeded that of grafted plants. Pistillate flowers of non-grafted plants emerged eight days prior to grafted plants; however, by the first harvest period vegetative growth of grafted plants was appreciably greater than that of non-grafted plants. Melon harvests were three to eight days earlier with non-grafted as compared to grafted plants at all three planting dates, but total marketable yields of grafted plants were 131%, 123% and 148% higher by planting dates on 12 May, 21 May, and 1 June, respectively, as compared to non-grafted plants. Fruit yields of grafted plants extrapolated to 119.4, 105.5 and 115.6 t·ha^-1, respectively, in plots at the 12 May, 21 May, and 1 June planting dates. Average fruit size was significantly larger in grafted plants (2.02 kg) as compared to non-grafted plants (1.35 kg). Mean SSC in fruit of non-grafted plants (10.7-11.8%) was not significantly different from that of grafted plants (10.3-11.4%). Grafted plants from the first planting date maintained growth and continued to set fruit for three more weeks after the last harvest of non-grafted plants, thus affording a longer market window while maintaining fruit quality.