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United States Department of Agriculture

Agricultural Research Service

Title: Introgression of Prunus Species in Plum

Author
item Okie, William

Submitted to: Proceedings of Anderson Stone Fruit Symposium
Publication Type: Proceedings
Publication Acceptance Date: March 10, 2005
Publication Date: March 18, 2005
Citation: Okie, W.R. 2005. Introgression of prunus species in plum. Proceedings of Anderson Stone Fruit Symposium. p. 5.1-5.19.

Interpretive Summary: “Introgression” is a big word meaning introduction of the genes of one species into the gene pool of another. This transfer can be a one-time thing, or if one parent is much better than the other, it may involve repeated backcrossing of an interspecific hybrid with one (generally the one with better fruit) of its parents. Within the stone fruits, plums have had the most extensive mixing and matching of species. Most of these Japanese plums are consumed as fresh fruit. Production in the United States is concentrated in California, where they are best adapted. Nearly all the plums shipped out of California are the result of crossing different plum species. Commercial production in California is dominated by a few major cultivars, and new cultivars become important only slowly. There are few breeding programs outside California, where the primary goals of increased size, firmness and quality have required no further use of primitive germplasm. Recent utilization of genetic resources of Japanese plum has been limited in the United States compared with that of many crops. Difficulties in collection, importation and quarantine through-put have limited the germplasm available. The trend towards a fewer breeding programs, most of which emphasize "short-term" (long-term compared to most crops) commercial variety development to meet immediate industry needs, has also contributed to reduced use of exotic material.

Technical Abstract: Within Prunus, plums have had the most extensive introgression of species. Use of exotic species for the other main stone fruits – peach, cherry, almond and apricot – has been minimal and mostly directed at rootstock development. Most Japanese plums (P. salicina hybrids) are consumed as fresh fruit. Production in the United States is concentrated in California, where they are best adapted. Commercial production in California is dominated by a few major cultivars, and new cultivars become important only slowly. There are few breeding programs outside California, where the primary goals of increased size, firmness and quality have required no further use of primitive germplasm. Recent utilization of genetic resources of Japanese plum has been limited in the United States compared with that of many crops. Difficulties in collection, importation and quarantine through-put have limited the germplasm available. Prunus is more difficult to preserve because of the large amount of space needed compared to small fruit crops, and the shorter life of trees relative to other tree crops because of disease and insect problems. Lack of suitable rootstocks has also reduced tree life. The trend towards a fewer breeding programs, most of which emphasize "short-term" (long-term compared to most crops) commercial variety development to meet immediate industry needs, has also contributed to reduced use of exotic material.

Last Modified: 4/16/2014