BREEDING MUSCADINE GRAPES FOR FLORIDA

 J. A. Mortensen


It was 1959 when we began testing muscadine cultivars and
selections obtained from breeding programs in Mississippi,
Georgia, and North Carolina. We have continued testing and
evaluating available muscadine material to date for longevity,
fruit yields, disease resistance, and adaptability to mechanical
harvest. Since 1972 we have made crosses at Leesburg to increase
emphasis on resistance to PD, uniformity of ripening, high
percentage dry scar, and fruit quality for fresh use, wine, or
juice.

Increased berry size is demanded by pick-your-own and fresh
market outlets; thus, larger-berried parents such as Granny Val,
Summit, Dixieland, Jumbo, or Nesbitt have been used as sources of
size. Seedlessness is needed in muscadines, and at least one
seedless selection developed by the late Mr. B. O. Fry of
Griffin, Georgia is currently of interest. Use of fertile
hybrids between bunch and muscadine grapes to transfer
seedlessness from bunch grapes to muscadines is under
investigation. A North Carolina cultivar of interspecific hybrid
makeup is seedless -- N.C. 74C039-1. Crosses were made with
pollen of this cultivar with Nesbitt, CA9-37, and CA9-50
muscadines and with AA12-3 interspecific hybrid. Wine cultivars
with good color and quality retention through fermentation are
being developed in cooperation with Dr. Bates. Resistance to
berry rot during the period of ripening has received increased
selection pressure in recent years among our muscadine
selections.

Table 1 gives the 14 currently recommended muscadines for various
purposes and uses. Best for white wine are Welder, Doreen, and
Dixie; for red wine Noble and Regale. Best pick-your-own bronze-
fruited varieties are Triumph, Summit, Fry, Dixie, and Dixiered.
The best pick-your-own black-fruited varieties are Nesbitt and
Jumbo. Only two cultivars appear suitable for fresh market:
Nesbitt and Summit. Other varieties either lack size, ripen
unevenly, or have a wet stem scar when harvested mechanically.

Table 2 lists the 31 muscadine varieties not currently
recommended for Florida and the reasons why they are not. Carlos
is excellent for uniformity of ripening and dry stem scar but
several vines have died of PD at Leesburg and at other Florida
locations. PD susceptibility is the reason we do not recommend
Carlos. Magnolia makes good white wine but the fruit ripens so
unevenly in Florida, and its susceptibility to ripe rot is so
evident that we cannot recommend it. Higgins was a fine old
female variety but susceptible to ripe rot, so is no longer
recommended. Sugargate has excellent fruit quality but yields so
poorly it is not recommended (See Table 2).