Grafting is an effective management strategy in watermelon crop against soil borne pathogens. Carolina strongback (SB) rootstock used for grafting, is resistant to both fusarium wilt and root knot nematodes which are devastating soil borne pests of watermelon. However, recent trials have shown that SB grafted plant bear fruits 7-10 days later than regulate plants leading to farmers losing early market which is more profitable. Further, tissue boron content in SB grafted plants were reported to be lower than regular watermelon nursery plants. Boron is a key micro-nutrient that involves in cell wall and cell membrane, pollination, pollen germination, cell division, translocation of carbohydrates and fruit development. We hypothesize that foliar application of boron will cure the boron deficiency in grafted plants and leads to early fruit set similar to regular watermelon nursery. To test this hypothesis, a field experiment was conducted at Edisto Research and Education Centre, SC. Two foliar boron applications at 30 and 50 days after transplanting significantly improved the pollen viability of SB grafted SP6 pollinizer at 60 days than control and non-grafted plants. Similar to pollen viability two foliar boron applications recorded the highest total fruit yield and tissue boron content than all other treatments. Highest gross, and net returns were observed with two foliar boron application treatments and lowest net returns were observed in one foliar boron application treatment. We will be repeating the experiment in 2025 to collect second year of data.
