By Bill Castle
The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center (CREC) plant improvement team has long been engaged in field research to evaluate new scions and rootstocks. That effort continues and has involved trials on public and private property.
While public sites are valuable, they are limited in number. Thus, most UF/IFAS trials are conducted cooperatively with citrus growers. When public and private sites are viewed together, a broad range of circumstances are encountered that call for flexibility in designing and managing those trials.
LEVELS OF ASSESSMENT
The UF/IFAS rootstock pipeline has three levels of assessment. Periodically, introduced rootstocks and those from the breeding program are assembled, propagated and set out in a screening trial for their initial evaluation, often at one location. When sufficient data are collected to reveal those rootstocks best suited for the next level of testing, usually smaller trials are planted, possibly each with a different scion and at two or three locations. Next, the “winners” are put into advanced trials that involve primarily larger, more grove-like plot sizes (20 to 100 trees) and fewer replicates.
Sometimes, plantings are established which are designed to be even more grove-like with larger plots and few replicates. These are as much demonstration projects as experiments and are comprised of well-advanced rootstocks.
Trials also originate by grower request. In some cases, progressive growers have “out of the box” ideas for trials on their own property that are worthy of pursuit. UF/IFAS vigorously pursues opportunities leading to a broad range of field situations.
Meeting with the cooperator as often as needed to convey and agree on the plan and the contributions of each partner helps reduce misunderstandings later. Discuss dates, who pays for what, harvesting, access, fruit income, field days and a host of other things covered in the UF Material Transfer Agreement to protect intellectual property.
Among the researchers, good communication is also essential. In the case of UF/IFAS, with three investigators, each having their own sources of new rootstocks, it can be challenging to assemble a collection of new materials for testing in a timely, coordinated manner. However, as opportunists, the plant improvement team is eager to seize offers from interested growers to plant what they can, when they can.
The website https://crec.ifas.ufl.edu/citrus-research/rootstock-field-data/ provides growers with user-friendly access to collective decades of UF/IFAS rootstock trial data.
Bill Castle is a professor emeritus at the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center in Lake Alfred.
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