Developing and evaluation of new watermelon hybirds and their heterosis [electronic resource].

Includes references.

This study was conducted during the period from 2001to 2005 to develop and evaluate new watermelon hybrids. Selfing and crossing were carried out in the greenhouse, while evaluations were conducted under low tunnels. Ten inbred lines of watermelon were used as parents of this study; nine were developed from the verities Charleston Gray, Congo, Crimson Sweet, Giza I, Klondike, Kodhi, Mehesny (a local variety), Peacock WR60, Sugar Baby and the 10 th was the inbred line 7150 of Spanish origin. These inbreeds were crossed in a half diallel mating producing 45 FI hybrids. Produced suds of 5 FI hybrids were insufficient and excluded from the evaluation. The ten parental inbred lines their 40 FI hybrids and the commercial FI hybrid Aswan (control) were evaluated in the field using drip-irrigation system. The parent Sugar Baby produced a high early yield (EY) in both seasons. The hybrids Giza I x Sugar Baby, Sugar Baby x kloadike Sugar Baby x Peacock and Charleston Gray x Klondike produced a high EY which were not significantly different from both the check hybrid Aswan and the parental lines Kodhi and Sugar Baby. The hybrid Charleston Gray x Klondike exhibited significant positive high-parent heterosis for EY in the two seasons. The two hybrids Charleston Gray x Klondike and Charleston Gray x Congo produced, significantly, the highest total yield (TY) being 36.54 and 36.49 ton/fed, respectively, without significant difference from the control which produced TY of 33.46 ton/fed and also without significant differences from the crosses Crimson Sweet x Congo, Crimson Sweet x Klondike, Crimson sweet x Mehesny, Crimson Sweet x Peacock, Giza I x Sugar Baby and Sugar Baby x Peacock.: The hybrids Charleston Gray x Congo, Charleston Gray x Klondike and Kodhi x Sugar Baby showed significant positive better-parent heterosis values for TY.. The hybrids Charleston Gray x Klondike and Charleston Gray x Mehesny significantly produced the heaviest fruits among all evaluated genotypes. Ten hybrids showed significant superiority over the check hybrid ranging from 21.2% to 66.1%. Out of them only 4 hybrids exhibited significant positive better-parent heterosis ranging from 17.8% to 23.7% Only two hybrids out of the 40 evaluated hybrids significantly surpassed their better-parents in fruit length (FL). The parents Charleston Gray, Congo and Peacock beside two hybrids produced elongate fruits, and cv. Klondike and 21 hybrids produced oval fruits The remaining cvs. and hybrids produced spherical fruits The genotypes that produced the least fruit rind thickness (FRT) in the two seasons were the parents Kodhi. Sugar Baby, Peacock and the hybrid Giza I x Sugar Baby. In the two -as. mast of the evaluated hybrids were not significantly different in FRT .from their better parents Le the parents having thin rind. The genotypes that produced fruits having the highest total soluble solids (TSS) content were the parent Klondike and tile hybrid Giza1 x Sugar Baby (l1.1% and ll.7%, respectively). The hybrid giza x sugar Baby was the only one which significantly surpassed the standard hybrid Aswan in TSS only'5 hybrids significantly surpassed their better-parents in fruit TSS with a range from 6.1% to 12:r% with the hybrid Kodhi x Charleston Gray having the highest estimate.

Summary in Arabic.

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