Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2009
Publication Date: 5/15/2010
Citation: Luan, F., Sheng, Y., Wang, Y., Staub, J.E. 2010. Performance of Melon Hybrids Derived From Parents of Diverse Geographic Origin. Euphytica 173:1-16.
Interpretive Summary: Melon is an economically important vegetable crop worldwide. The U.S. is number three in worldwide production of this crop species. The yield of U.S. Western Shipping melon has plateaued in the last 20 years, and there is a need to develop biotechnologies and breeding methodologies to overcome this plateau. If hybrid (one plant mated with another) combinations could be found that would allow horticultural performance to be maximized, then novel high-yielding cultivars could be produced more rapidly and efficiently (lower cost). Thus, experiments were planned and executed to use biotechnologies to identify the most diverse melon plants and cross them strategically to produce hybrids for testing in the open-field. If differences in performances could be identified and these associated with their genetic nature, then biotechnologies could be used in the future to predict the best hybrids. Results indicate that even though the biotechnologies used could detect genetic differences between melon plants and allow for crossing of very different plant types, these technologies were not predictive of horticultural performance (yield and quality). Nevertheless, data indicate that some of the hybrids produced in such genetically wide crossings were novel and with further genetic manipulation (breeding) could provide for important, high yielding melon plants with improved overall horticultural performance when compared to modern cultivars now in production. The information gained will assist plant breeders in incorporating the selected plants into their breeding programs to improve melon performance. This will inturn provide for the release of novel cultivars to improve the U.S. grower global competitiveness.
Technical Abstract: Genetic relatedness and phenotype are important factors that govern the expression of heterosis in hybrid progency. Since this relationship is not well understood in melon (Cucumis melo L.), three monoecious and andromonoecious melon lines of diverse Chinese [Peoples Republic of China (PRC)] origin were crossed to the andromonoecious U.S. Western Shipping market type 'Top Mark' (TM) and the andromonoecious, highly branched TM derived line H16 to determine parental combining ability and heterosis for five yield component traits in three test environments [open-field (USA), and energy-saving and plastic greenhouse (PRC)]. Random amplified polymorphic DNA (RAPD)- and simple sequence repeat (SSR)-based genetic distances (GD) among and between parents (5) and their hybrids (6) were calculated and compared to phenotype. These germplasms were evaluated for lateral branch number (LBN), days to 50% flower (DF), fruit number and weight per plant, and fruit length (L): diameter (D) ratio. General combining ability was significant for all characters, except for L:D in all locations, and LBN and DF in the plastic greenhouse environment. Both market types were discriminatory and provided similar assessments of relatioinships among parents and hybrids. Although dramatic performance differences were detected between parents and among F1 hybrid progeny, a strong relationship between GD and heterotic effects was not detected.