White clover’s claim to fame comes from the occasional presence of leaves with four leaflets, i.e., the four-leaf clover that brings good luck to its discoverer. Otherwise, white clover is best known for its use as a high quality forage, or for its presence as a ubiquitous lawn weed.
However, white clover has many genes that affect leaf color and shape. These genes are very rare, such as the gene for red midrib mark, which is a herringbone pattern that runs down the center of each leaflet in a bold red color. These traits can be strikingly beautiful, particularly if combined with other, and can turn clover into an ornamental plant for use in flower beds.
How these leaf traits are inherited and why white clover has so many rare leaf traits and has puzzled geneticists and breeders for many years. The better these traits are understood, the easier it should be for breeders to develop new ornamental varieties.
Researchers at the University of Georgia and the Samuel Roberts Noble Foundation in Ardmore, Oklahoma are starting to solve the mystery of leaf trait inheritance in white clover. Using both modern molecular-based genetics tools and classic breeding methods, the location of three leaf traits—including the elusive 4-leaf trait-- were mapped onto a white clover molecular map and the inheritance of two leaf mark traits was determined. Results of the study can be found in the July-August issue of Crop Science.
The researchers developed two populations of plants containing many of the leaf traits found in white clover. Over two years, the two populations were grown in two locations, and trait data for each plant were recorded during the winter and summer. Tissue samples were collected from each plant and DNA was extracted, and molecular markers were analyzed.
The study confirmed the location of the gene for red fleck mark and mapped the gene for red midrib to a nearby location, thus resolving a century-old question as to whether these leaf traits were controlled by one gene or two separate genes.
More excitingly, the researchers found the gene that turns ordinary three-leaf clovers into the coveted four-leaf types. Normally, this trait is difficult to find, as it is masked by the gene for three-leaflets and because the presence of the trait is strongly influenced by the environmental conditions. Now that molecular markers are available to detect the presence of the gene for four-leaves, breeders can work with it, even when environmental conditions do not permit the four-leaf trait to be seen.
“This is a great time to be involved in white clover breeding” said Wayne Parrott, the senior researcher of the study. “We now have the tools to make it easier to breed important traits in this species which has historically proven to be a challenging plant to work with. In addition, we can hasten the development of new white clover cultivars bred for a variety of uses by screening new generations of plants for traits of interest before they even reach the field trial stage, significantly reducing the time and resources needed for new releases of white clover.”
Research is continuing at the University of Georgia and the Samuel Roberts Noble Foundation to map genes involved in other leaf traits and many other white clover traits. The current study was partially funded by the Samuel Roberts Noble Foundation and the Georgia Agricultural Experiment Stations.
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A University of Georgia team has pinpointed the gene that turns an ordinary clover, with three leaves, into the supposedly lucky four-leaf type. ...
Jul 1, 2010 ... Gene finds could give us all the four-leaf clovers we want, as well as other rare coloured and patterned varieties, and new ornamental ...