Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Vegetable

This study was conducted during the period from 2011 to 2016 at Kaha Vegetable Research Farm (KVRF), Qalubia Governorate to evaluate some watermelon landraces collected from ten different local geographic regions of Egypt to increasing their homogeneity through inbreeding and selecting the best individual genotypes during four successive generations to produce 15 inbred lines. Seedling inoculation procedures were used to screen 15 lines of watermelon ecotypes for resistance to fusarium wilt. Of these ecotypes, 5 lines significantly showed resistance to fusarium oxysporum. And used four lines as female parent Suhag 1(P1) - Suhag 2(P2)-Sinaa (P3)-Bir El-Abd 2(P4); and the cultivars Giza1 (P5), Crimson Sweet (P6) and the line (Beni Swif) (P7) were used as male parents in a line X tester mating design to produce twelve hybrids. Parents and hybrids were evaluated to horticultural characters and resistance to fusarium wilt. Biochemical parameter such as phenolic content and some enzymes in three watermelon hybrids shown susceptible, moderately resistance and resistant to fungus fusarium oxysporum f.sp. niveum. Estimates of coefficient of variance (C.V %) values showed that, most of the breeding lines were highly homogeneous and could be considered pure lines. All parents and crosses were significant with positive value for all traits studied. With respect to heterosis effects, cross P2 XP6 gave highest values with significant effect for plant fresh weight, total yield /plant and fruit weight for mid-parent and better parent. Crosses P2X P7, P3X P5 and P4 X P6 gave earliest female flower over mid-parent and better parent, cross P4XP6 gave highest values with significant effect for rind thickness for mid-parent and better parent. Cross P1XP7 gave highest values with significant effect for TSS for mid-parent

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