Citrullus lanatus (Thunb.) Matsum. & Nakai - Cucurbit Breeding ...

Many of the yield trials run each year around the United States show few differences for yield among
the experimental entries being evaluated. The screening of a diverse set of watermelon cultivars for fruit yield
presented herein showed that there is variation for yield, and that sources of high yield are available.
Furthermore, yield was strongly dependent on cultivar, even though influenced by environmental factors
(including cultural practices), and probably could be improved through plant breeding. It is now apparent that
the lack of genetic variation and the slow improvement in yield often mentioned by watermelon breeders may
most likely be a result of the greater emphasis on traits other than yield, as well as the lack of diversity for yield
among the modern cultivars. In any case, there is a need to identify sources of high yield, both as fruit weight
and fruit number, and to use those sources to develop high yielding, but adapted lines for use by plant breeders.
Important traits such as fruit quality and disease resistance should be incorporated into those high yielding lines
before they are used to develop new cultivars. This should also result in an increase in the genetic diversity of
modern cultivars.
Significant genetic diversity in RAPD markers has been observed among watermelon accessions from
different geographical areas and from related species such as C. colocynthis (Levi et al., 2001). Now that
phenotypic variability for yield in watermelon has been demonstrated, and high yielding cultivars identified, the
next step would be to evaluate the USDA-ARS germplasm collection for fruit yield at several locations around
the United States, including accessions originating from different areas of the world.
Literature Cited
Brar, J.S. and A.S. Sidhu. 1977. Heterosis and combining ability of earliness and quality characters in
watermelon (Citrullus lanatus (Thunb. Mansf.). II. Journal of Research. 14: 272-278.
Brar, J.S. and B.S. Sukhija. 1977. Hybrid vigor in inter-varietal crosses in watermelon (Citrullus lanatus
(Thunb) Mansf.). Indian Journal of Horticulture. 34: 277-283.
Ferreira, M.A.J., L.T. Braz, M.A. Queiroz, M.G.C. Churata Masca, and R. Vencovsky. 2002. Capacidade de
combinacao em sete populacoes de melancia. Pesquisa Agropecuaria Brasileira. 37: 963-970.
Gill, B.S. and J.C. Kumar. 1988. Combining ability analysis in watermelon (Citrullus lanatus Thunb. Mansf.).
Indian Journal of Horticulture. 45: 104-109.
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