By Peter Chaires
Based on the performance of a single mother tree, the University of Florida’s Marathon mandarin was released and licensed into a revised version of the FAST TRACK model in 2019. Having learned from the growing pains of earlier FAST TRACK variety launches, the Marathon model (Suite IV) was designed to be more user friendly and flexible.
Photo by Peter Chaires
Rather than restrict early commercial production to those growers who participated in an earlier trial opportunity, Marathon was made available for licensing and planting at any time. There are no head-start advantages as with previous varieties. Growers can plant trials of any size and number they wish, or venture into commercial production at whatever scale matches their risk tolerance.
MATURE TREES LOOKING GOOD
The oldest Marathon trees are 6 years old and are planted a short distance from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center in Lake Alfred. All the trees in this planting are on sour orange rootstock. A small group of growers recently toured the block with Fred Gmitter, UF/IFAS citrus breeder, to make observations about tree health, cropping and fruit quality. The visit did not disappoint.
The Marathon trees are showing good overall health and growth. Leaves are dark green, and canopies are full. Though the trees have not been pruned or hedged, the crop load is good. However, the crop load is variable from tree to tree, perhaps because of very heavy cropping in the previous season.
Early September peel coloration is approximately 50% on most fruit, though the fruit could be spot picked for color. Many fruit were found to be of good eating quality in the first week of September this season. If past behavior is duplicated, the eating quality should continue to improve, as well as the external color.
This fruit appears to have potential as a retail commercial variety or through direct consumer sales (gift fruit or roadside stands).
Marathon trees growing on sour orange are quite vigorous, but trees grown on US-897 have been vigorous as well. Normal nutritional practices seem adequate to support good growth and fruiting. Excessive nitrogen can lead to granulation, as was learned earlier with these trees.
Though symptoms of HLB can be found, this variety is exhibiting a high degree of HLB tolerance. Like many other mandarin hybrid varieties, Marathon is sensitive to alternaria, so methods developed to manage this disease should be
considered to increase yields of marketable, high-quality fruit.
Photo by Peter Chaires
CONSERVATIVE APPROACH
Growers have been conservative in their approach to the Marathon mandarin. Some growers had planted larger acreage of earlier FAST TRACK releases only to struggle with consistent production and fruit size. This experience has clearly had an impact on the progress of Marathon and adds to the significance of field visits and grower and nursery observations.
Growers can expect to harvest and pack fruit in the third year. This timing will vary by rootstock, horticultural care and growing conditions.
GETTING TREES
Nursery and grower sublicense agreements for Marathon are available through New Varieties Development & Management Corp. Contact Lucy Torres at Lucy.Torres@FFVA.com or 321-214-5200. Growers must execute an agreement and pay a one-time registration fee of $150. The Florida royalty is a one-time fee of $2 per tree, which is paid by the grower to the licensed nursery at the time the grower takes possession of the trees.