citrus

OLL Sweet Oranges Producing Pre-HLB Fruit Quality

Josh McGill Tip of the Week, Varieties

By Jude Grosser, Fred Gmitter and Maria Brenelli

The new OLL (Orie and Louise Lee) series of sweet oranges (OLL-4, OLL-8 and OLL-20) are very high-quality processing sweet oranges that generally produce higher soluble solids and better juice color than Valencia. OLL trees are more vigorous than Valencia, and anecdotal evidence suggests they are slightly more HLB-tolerant than Valencia.

Trees of OLL-8 on rough lemon rootstock at Orie Lee Family Groves in St. Cloud, grown without psyllid control, have produced 7 pounds solids per box for four consecutive seasons. Adjacent Valencia trees on rough lemon in the same block have averaged approximately 6 pounds solids per box.

sweet oranges
OLL-4

More recently, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers have been evaluating a large population of OLL somaclone-derived nucellar seedling clones. Trees are now nine years old and have never had formal psyllid control. Juice quality data this season from the population identified nine clones with Brix greater than 12 and soluble solids per box greater than 6.5.

Tree health continues to be exceptional on several of these clones. The best clone, FBR4-T4, produced 13 Brix and 7.22 pounds solids per box. Superior clones are being propagated for advanced trials and entered into the Florida Parent Tree Program.

UF/IFAS researchers have also identified two new OLL clones that are maturing in early January, approximately six weeks earlier than the other OLL clones. These have potential as mid-season oranges for both processing and the fresh market. These new OLL sweet oranges hold great promise for improving Florida not-from-concentrate juice quality.

The next fruit display will be held at the UF/IFAS Citrus Research and Education Center (CREC) on Feb. 22 from 10 a.m. to 12 p.m. This event features late juice oranges. All commercial growers and industry representatives are welcome. No pre-registration is needed.

Jude Grosser and Fred Gmitter are professors, and Maria Brenelli is a graduate student pursuing her master’s degree in horticultural sciences — all at the UF/IFAS CREC in Lake Alfred.

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