Recurrent selection

Gaertner, V. and Goldman, I.L., Pigment distribution and total dissolved solids of selected cycles of table beet from a recurrent selection program for increased pigment, J. Am. Soc. Hort. Sci, 130, 424, 2005. 

The fortunate constellation of scientists at Wisconsin facilitated further achievements toward increasing pigment content in red beets. In a recurrent selection program, betalain contents of red beet crops were enhanced by 200%. This example should encourage both food scientists and plant breeders to join forces and invest in the improvement of promising color crops. 

Mike Lassner (Verdia Inc.) presented examples of the usefulness of directed molecular evolution as an in vitro process that more easily achieves what was traditionally attempted via reproductive crossing and recurrent selection (plant breeding). Proteins may be engineered that have specific desirable characteristics via methods that "evolve" the basic underlying DNA. For example, the outcome can be enzymes with improved kinetic properties that result in enhanced primary production, or proteins that remain operational under extreme conditions. In addition, compositional proteins may be enhanced to provide functional performance that was not achievable via conventional methods. 

Brim, C.A. C.W. Stuber. Application of genetic male sterility to recurrent selection schemes in soybeans. Crop Sci. 1973, 13, 528-530. 

Nyhus, K. a., W. a. Russell, W. D. Guthrie, and C. A. Martinson, Reaction of two maize S3mthetics to anthracnose stalk rot and northern com leaf blight following recurrent selection for resistance to Diplodia stalk rot and European com borer. Phytopathology, 79, 166-169 (1989). 

Individual plants showing the desired phenotype will be selected and either generatively or veg-etatively propagated (individual selection), or positive or negative mass selection techniques can be applied. Selection is traditionally the most common method of genetic improvement and the majority of varieties and cultivars of essential oil crops have this background. Due to the fact, however, that almost all of the respective plant species are allogamous, a recurrent selection is necessary to maintain the varietal traits, and this has especially to be considered if other varieties or wild populations of the same species are nearby and uncontrolled cross pollination may occur. 

Schipper, H. and Frey, K.J. (1991a) Observed gains from three recurrent selection regimes for increased groat-oil content of oat. Crop Sci. 31, 1505-1510. 

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