The invention belongs to the technical field of breeding of
cucurbitaceae vegetable. An interspecific
hybrid F1 (Yong
rootstock No. 6) of cucurbit (a melon
rootstock) is obtained by hybridizing a female parent of a stable inbred line J03-2-3-2-1-5-7-4 by multi-generation of directed autocopuation screening of cucurbit materials originated from Japan and a male parent of a stable inbred line YH2-3-3-2-1-4-2-6 by multi-generation of directed autocopuation screening of local
Lagenaria species produced in Ningbo. The melon
rootstock selectively bred with the method provided in the invention meets objectives of breeding and has moderate growth potential,
high resistance to die-back and
root rot, well-developed roots, strong stalks, strong ability in absorbing
nutrient, low degree of vain growth and robust hypocotyls which are not easy to become hollow, and therefore the melon rootstock is favorable for
grafting. The melon rootstock has good
grafting affinity and strong
symbiosis affinity, and a
survival rate over 95% is obtained for the
grafting of the rootstock onto the watermelon specie ''Zaojia'' (8424). The engrafted melon rootstock is low temperature-resistant,
moisture-resistant and barren-resistant; after field planting, the root and overground part of a grafted
seedling grows fast and has sound growth potential, and the period of first harvest of the grafted
seedling is 5 days earlier than that of a self-rooted
seedling, the fruition rate is high and stable, weight of single fruit and fruit shape can substantially maintain the same, melon
skin is not thickened,
sugar degree of the grafted seedling is higher than that of the self-rooted seedling,
sugar degree gradient is small, quality of the watermelon is not affected, and good adaptability is obtained.