Assessment of Fusarium wilt resistant Citrullus sp. rootstocks for yield and quality traits of grafted watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai)

Abstract

The experiments were conducted to characterize eighteen Fusarium wilt resistant Citrullus accessions for their root parameters and to evaluate their performance as rootstocks for vigour, earliness, quality, yield and tolerance to sudden wilt disease of grafted watermelon in comparison with Cucurbita and Lagenaria rootstocks. Significant variations were observed among the rootstocks for all the root traits under study. The length and diameter of the rootstock hypocotyl were found to be an indicator of the robustness of the root system. A significant influence on vine length and earliness of the grafted crop was observed across different rootstocks. The grafts on Citrullus rootstocks could maintain the oblong fruit shape of the scion compared to those onto Cucurbita hybrid and Lagenaria rootstocks which yielded from flat-globe to spherical shaped fruits. A wide variation of TSS and carotenoid content was observed upon grafting while the pulp pH remained largely unaffected. An increase of average fruit weight by 82.37% and yield per plant by 112.15% in grafts onto RS-18 and RS-10 respectively were recorded. The grafts onto rootstocks viz., RS-10, RS-21 and RS-25 also exhibited reduced severity of sudden wilt; hence are of value in regions prone to both Fusarium wilt and sudden wilt diseases. Overall, the Citrullus accessions viz., RS-10, RS-11 and RS-18 were found to be promising in comparison to Cucurbita hybrids and Lagenaria rootstocks. Grafting onto resistant rootstocks can help in environment-friendly management of Fusarium and sudden wilt diseases in watermelon without compromising the yield and quality.