The effectiveness of growth cycles on improving fruit quality for grafted watermelon combinations

Abstract Two growth cycles per year, i.e., for early growing season (EGS) and late growing season (LGS) production, both of which are widely preferred in temperate climates, have been investigated for their effects on fruit quality attributes such as appearance; firmness; the content of total soluble solids, sugars, and total phenol; and antioxidant activity. Two watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] cultivars (cv. 'Anthem F1' and cv. 'Crimstar F1') were used as scion. Two C. maxima × C. moschata hybrids (cv. 'Shintoza F90' cv. 'Obez') and one Lagenaria siceraria rootstock cv. 'Macis' were used as rootstock. Self-rooted and self-grafted plants were used as controls. EGS resulted in a reduction of fruit shape index, rind thickness, juice pH, hue values, and glucose content as compared to LGS for both the cultivars. On the other hand, total soluble solids of cv. 'Crimstar', fructose of cv. 'Anthem', and the antioxidant activity of cv. 'Anthem' increased. The total phenol content was unaffected by the scion/rootstock combinations or growth seasons for both the cultivars. Most of the fruit quality attributes increased when a specific rootstock/scion combination and growth season was used and these combinations may change in relation to cultivar. It is important to evaluate and select suitable scion/rootstocks for each growth condition created by ecology and growth cycle to guarantee high fruit quality