|DELA CRUZ, A.|
Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2005
Publication Date: 8/20/2005
Citation: Fitch, M.M., Leong, T., Akashi, L., Yeh, A., White, S., Dela Cruz, A., Santo, L., Ferreira, S., Moore, P.H. 2005. Clonaly propagated and seed-derived papaya orchards: 2. comparison of yields. Journal of Horticultural Science and Biotechnology. 40(5)1291-1297.
Interpretive Summary: Papaya seedlings segregate as females or hermaphrodites but only the hermaphrodite is grown commercially. Seedlings are multiple-planted and thinned to a single hermaphrodite, a practice that is wasteful of seed, labor, and resources. Researchers at ARS, HARC, and the University of Hawaii compared growth and yield of traditionally planted seedlings with hermaphrodite plants propagated by two clonal propagation methods, rooted cuttings and micropropagation. Clonally propagated plants were shorter than seedlings, bore flowers earlier and lower on the trunk compared to thinned seedlings. Fruit were harvested 1-3 months earlier compared to the thinned seedlings resulting in higher overall yields. The savings in resources and labor in addition to earlier harvests and higher overall yields make the clonally propagated plants an economically attractive alternative to seedling transplants for growers.
Technical Abstract: Gynodioecious papaya seedlings in commercial cropping systems in Hawaii are typically multiple-planted and thinned upon flowering to a single hermaphrodite because seedlings segregate for sex expression. Use of clonally propagated hermaphrodites would eliminate the over-planting practice and may provide other advantages. Yields of clonally propagated hermaphrodites were compared with single- and multiple-planted seedlings in three fields on two islands in Hawaii. Cloned hermaphrodites were either rooted cuttings or in vitro micropropagated plants. Clonally propagated plants bore ripe fruit one to three months earlier than thinned seedlings and had significantly higher early and cumulative yields. At each site, cumulative yields of thinned seedlings never reached the same level as those of clonally propagated plants. The yield benefit from clonally propagated plants was greatest at Keaau, the lowest sunlight and least productive test site.