Location: Subtropical Horticulture ResearchTitle: Broad-sense heritability estimates for fruit color and morphological traits from open-pollinated half-sib mango families) Author
|Schnell ii, Raymond|
|Winterstein, Michael - Mike|
Submitted to: HortScience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/31/2009
Publication Date: 9/1/2009
Citation: Brown, J.S., Schnell Ii, R.J., Ayala Silva, T., Moore, J.M., Tondo, C.L., Winterstein, M.C. 2009. Broad-sense heritability estimates for fruit color and morphological traits from open-pollinated half-sib mango families. HortScience. 44(6):1-5. Interpretive Summary: Consumers usually have strong preferences about the appearance of mangos (Mangifera indica L.), as for other fruits and vegetables, and breeders must take this into consideration when releasing new varieties. Often this perceived preference is based on a past variety that made a strong impression on consumers, and frequently the preferred type is not necessarily the most flavorful, or has other horticultural characteristics less preferred by producers or shippers. Historically, the breeding of many tree fruit crops has been done by finding chance “sports” or mutations, or progeny from planned or unplanned crosses. This is the historical manner in which mango breeding has been done, although it is now becoming more incorporated into structured, multi-year programs. Hence, the quantification of the measurement of breeding traits has become more important. Mango fruit color is very important in Florida and for shipment and sale in northern states, with a strong preference existing for mangos with a red overlaid blush. Therefore, the knowledge of the heritability and having some idea of the inheritance of important traits in mango has become important. Portable colorimeters, used to quantify color in many fruits and vegetables, have been shown to be effective in assessing mangos also. In this experiment, the variability of several color parameters was measured within and across five open-pollinated maternal half-sib families, as well as for three horticultural traits and for one disease reaction response (anthracnose) on the fruit. Results indicated that it should be very feasible to breed for all traits measured. Variability within families was greater than that across families, and dominance seemed to play an important role in these traits, as did additive variance and gene interaction.
Technical Abstract: Abstract. 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 work within the parameters of acceptance. Mango selection using multi-year breeding programs is replacing the former method with which most earlier cultivars were selected, namely from chance seedlings of planned or unplanned crosses. Therefore, quantification of heritability of many breeding goals has become important. While some mango breeding traits are categorical, being controlled by relatively few genes, many more are based on quantitatively inherited traits, especially those influenced by interaction with environment. Basic fruit color patterns are likely controlled by relatively few genes. However the expression of finer colors and shades are complexly inherited and best measured by colorimeters. 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 all traits, variance within families was greater than that among families, illustrating high heterozygosity of the clones studied in this trial and the very probable importance of dominance and epistasis.