Mineral Contents in Melon Plants (Cucumis melo L. cv. ‘Prince’) and Fruit Quality Influenced by Grafting on Squash Root Stocks and Calcium Applications in Soil

Abstract

This study was carried out to investigate the effects of grafting of melon scions (Cucumis melo L. cv. ‘Prince’) on squash root stocks (Cucurbita maxima × C. moschata cv. ‘Shintosa No. 1’) while fertilizers containing calcium were applied in soil in vinyl plastic greenhouses where the plants were grown.
The grafted melon plants grew more vigorously and bore larger fruits than the non-grafted melon plants. However, the quantity of soluble solids decreased significantly in fruits of the grafted melon plants, and further, the flesh color and aroma of the fruits were worse than those of the non-grafted melon plants. Fermentation of fruits of the grafted melon plants occurred more quickly than in fruits of the non-grafted melon plants. Thus, the quality of harvested fruits was better in the non-grafted melon plants than in the grafted melon plants.
The grafting treatment influenced mineral contents and fruit quality. In grafted melon plants, contents of nitrogen, potassium and carbon increased significantly in fruits, and the potassium content increased in leaves. The calcium content in fruits was lower in grafted melon plants compared with non-grafted melon plants. The quantity of calcium content in fruits was inversely correlated with the quantity of potassium contents in leaves. It was observed that fermentation of fruits occurred earlier and more rapidly when the calcium contents in fruits became lower. It is commonly believed that increasing the calcium content in fruits may delay fermentation. However, the application of calcium-containing fertilizers to the soil in greenhouses was not effective in increasing the calcium content of fruits.