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  • Author or Editor: J. Michael Moore x
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Abstract

Effects of deletion and enhancement of 280–315 nm ultra-violet (UV-B) radiation on pea (Pisum sativus L.), potato (Solanum tuberosum L.), radish (Raphanus sativus L.), and wheat (Triticum aestivum L.) plants were examined at a 3000 m elevation field site, which provided a 49% increase in midday effective (biologically weighted) UV-B radiation relative to near sea level. Wheat plants grown under Aclar or cellulose acetate film, which transmit UV-B radiation, were shorter than plants grown under Mylar film, which excludes UV-B radiation. Effective UV-B radiation levels at solar noon in the open and under the Aclar and cellulose acetate were 61, 55, and 44 mW m−2, respectively. There were no significant differences in potato, radish, and wheat dry weights attributable to UV-B radiation among the above treatments. The dry weights of all 4 species and pea and wheat plant height were not significantly decreased by a supplemental enhancement of 32 mW m−2 effective UV-B radiation from cellulose acetate filtered FS-40 sunlamps for 6 hours each day, relative to control plants that received only solar UV-B radiation. The results suggest that wheat plant height is more sensitive to deletion of UV-B radiation than the other parameters measured, and that the 4 species studied can tolerate the level of enhanced UV-B radiation used with concomitant high levels of visible radiation with no significant reduction in dry weight accumulation.

Open Access

The visual appearance of mangos is a primary factor in determining consumer acceptance and sale, similar to other fruit and vegetable commodities. Even if the appeal of visual appearance is based on consumer perception rather than on established quality factors, breeders must usually select within the range of acceptance, at least in some countries. Mango selection using multiyear breeding programs is slowly replacing the former method by which most earlier cultivars were selected, namely from chance seedlings either from planned or unplanned crosses. The knowledge of heritability of traits as they are controlled by genetics and experimental design and the effects and interaction of these two sets of factors on achieved gain have become more critical. The use of portable colorimeters has been shown to give repeatable scores in a quantitative, three-dimensional space for fruits and vegetables. In this experiment, we calculated broad-sense heritability estimates for five color traits, three morphological fruit traits, and one disease resistance trait (anthracnose expressed on the fruit). Estimates were found to be relatively high, indicating good potential for improvement through breeding. For nearly all traits measured, variance within families was greater than that among families, illustrating the likely importance of heterozygosity, dominance, and epistasis in these crosses. The careful estimation of heritability and repeatability will help prioritize and increase the efficiency of trait improvement as breeding methods become more sophisticated and competition for funding increases.

Free access