Quiescent intense (qi): a gene that affects young but not mature fruit color intensity in Cucurbita pepo

Jack O'Lantern, a cultivar of the pumpkin group of Cucurbita pepo that has intense-colored young fruits, was crossed with Vegetable Spaghetti, a cultivar of the vegetable marrow group that has light-colored young fruits and genotype d/d I-1/I-1 I-2/I-2. The F1 plants, regardless of the direction of the cross, had light-colored young fruits. Young fruit color was observed to segregate in accordance with a 3 intense: 13 light ratio in the F2, indicating that two genes, one dominant and one recessive, are interacting. By crossing Jack O'Lantern with tester stocks of known genotypes, the dominant gene was identified as L-2. The recessive gene, previously undescribed, is herein designated quiescent intense (qi), as it intensifies young fruit color but was observed to have little or no effect on intermediate-age and mature fruit colors. The young fruits of Verte Non-Coureuse D'Italie, a cultivar of the cocozelle group, are intense-colored. F1 plants of the cross between this cultivar and Jack O'Lantern had intense-colored young fruits, but F1 plants of the cross between this cultivar and Vegetable Spaghetti had light-colored young fruits. Therefore both Verte Non-Coureuse D'Italie and Jack O'Lantern are qi/qi, while Vegetable Spaghetti is Qi/Qi.