At Your Service

USDA’s citrus breeding team features four key scientists, and many more behind the scenes. Dr. Randy Niedz is researching the biotechnology side of the equation. He is presently working on tools that will enhance the team’s ability to develop varieties that can survive and thrive in present conditions. One of his specific objectives is developing efficient genetic transformation methods for citrus including methods to transform mature citrus tissue. One advantage of mature tissue transformation is that it bypasses the juvenility phase and allows for earlier tree/fruit evaluation, thus accelerating the development of disease resistant citrus trees.

 

Dr. Kim Bowman is best known for his work on new citrus rootstocks that are well adapted to Florida soils, pests, and diseases. Rootstock development is a complicated issue, requiring extensive trial and analysis. The current focus of the rootstock program is the development of an improved sour orange or Supersour.

 

On the scion side of things, Dr. Greg McCollum and Dr. Ed Stover are front and center. Dr. McCollum, an expert in postharvest physiology, works closely with advanced variety selections. He is responsible for field trials and has worked extensively on sensory and chemical flavor analysis of new varieties, as well as the rescue, protection, and preservation of elite citrus germplasm that is at risk in the field. In recent years, McCollum has produced more than 1,000 unique mandarin hybrids (from five parental combinations); the goal is high-quality, easy peel seedless alternatives.
Stover is the newest member of the team and is active in producing new mandarin hybrids, making initial selections of promising material — as well as the development of advanced grapefruit — perhaps expanding the grapefruit market with earlier maturity and attracting new grapefruit consumers with lower acid, non-bitter alternatives and sweet orange types.

 

With all fruit types, parental combinations are focused on generating progeny with HLB and canker resistance, top quality, and diverse maturities. Bowman and Stover are working hard to develop HLB resistance and other priority traits using biotechnology.

The overarching goals for this team effort are: flavor and convenience for the fresh citrus consumer; expanded utility and fruit quality for the processor; enhanced throughput from the breeding system; horticultural viability; and profitability for the grower.
It is important nurseries and growers have an understanding of how public resources are being directed toward citrus breeding, the individuals involved, and the process. Clearly, the proof is in results and releases. Watch this column for periodic updates.