Recent articles in trade press about the tolerance of LB8-9 ‘Sugar Belle’ has captured the attention of many growers (domestic and international). The phone at New Varieties Development & Management Corp. (NVDMC) has been abuzz with questions and curiosities. With appropriate care, the ‘Sugar Belle’ trees maintain a healthy canopy as well as produce and hold fruit. The increased planting of lemons appears driven by a similar motivation. The trees show HLB symptoms, but keep right on going. When it comes to selecting a variety, not all growers are looking to varieties to feed their traditional market channels.
For some, selecting a variety is pretty straightforward: I’ll take the green ones. The preeminent characteristic is disease tolerance. Growers need to produce a crop, hold it to maturity, and make money. Growers who have grown round oranges for generations are hedging their bets with a block or two of lemons or LB8-9 ‘Sugar Belle.’
What Else is Out There?
The good work of the breeding programs to chase tolerance and use only breeding parents with a demonstrated propensity to pass tolerance to progeny will certainly help. The Citrus Research & Development Foundation (CRDF) is placing increased emphasis on review of trials and available data. Good work is underway to follow up with healthy trees in otherwise unhealthy sets, and healthy limbs on otherwise unhealthy trees. However, casual observations also can sometimes be powerful.
Case in point: The Florida Nursery, Growers & Landscape Association Citrus Nursery Division held a meeting in Apopka recently. Part of the sidebar discussions among attendees included the amazing health and vigor of the ‘Gold Nugget’ mandarin. NVDMC originally brought the ‘Gold Nugget’ to Florida in hopes of finding an alternative to the ‘Honey Tangerine’ for the late season. As is typical with new mandarins in Florida, all of the early trees were grafted onto ‘Cleo’ liners. The trees grew well and looked decent, but did not produce enough fruit to be commercially viable. As HLB continued to wreak havoc on old-line varieties, the ‘Gold Nugget’ seemed to hold its own. The worse everything else looked, the better the ‘Gold Nugget’ looked. The oldest planting of ‘Gold Nugget’ mandarins was at Conserv II. At the time this article was written, the front-end loaders were closing in on the block, but the trees were still standing. A small group of nursery owners drove out to see the trees. As you can see from the photos, the trees remain dark green with a thick canopy, despite 14 to 18 months without irrigation, pest control, or nutrition.
Questions and Answers
As the group stared at the trees, the key question was why? Is what makes ‘Gold Nugget’ tolerant the same thing that makes other varieties tolerant? If a tree infects more slowly than others, is it still doomed, but it just doesn’t know it yet? Industry producers will continue to make observations and ask the questions. The scientific community will continue to research answers. And someone out there is managing the information.
NVDMC recently converted its ‘Gold Nugget’ contract from trial only, to also include dooryard and commercial production. This variety is a natural fit for dooryard growers. The jury is still out on its commercial utility in Florida, but more growers should be working with it. We now know ‘Cleo’ was not the best choice for ‘Gold Nugget.’
‘Gold Nugget’ is not fond of ‘Cleo.’ We need to get trees onto C-35, trifoliate, and trifoliate hybrids and see how it does. It crops well in other warm humid areas, it should crop here.