Part B – The UF/CREC-Citrus Improvement Program’s Field Trial Evaluations (Complementary to Part A- the UF/CREC Core Citrus Improvement Program)

Part B - The UF/CREC-Citrus Improvement Program's Field Trial Evaluations (Complementary to Part A- the UF/CREC Core Citrus Improvement Program)

Report Date: 09/09/2020
Project: 18-039-C   Year: 2020
Category: Plant Improvement
Author: Jude Grosser
Sponsor: Citrus Research and Development Foundation

 Significant genetic variation in OLL sweet orange seedling population identified (research block 13-W, Orie Lee Family Groves, St. Cloud):  many of the trees again tested PCR negative for CLas (after 6 years in the field with no psyllid control).  Clones showing high soluble solids and/or early maturity were propagated for further study. Significant genetic variation in Vernia sweet orange seedling population and various cybrids (Mathew Block, Lee Alligator Grove and CREC): multiple clones showing early maturity (December) and two clones with higher soluble solids were propagated for further study.  Propagation of best ‘gauntlet’ rootstocks: The first gauntlet rootstock hybrid containing SugarBelle as a parent (LB8-9 x S13-15-16) planted in the field with a CLas-infected Valencia scion that has grown vigorously and shows no HLB symptoms after 2 years was successfully propagated by cuttings and also introduced for TC propagation with Agromillora and Phillip Rucks TC lab. The best performing ‘gauntlet’ selection S10xS15-12-25 (produced from a cross of salt tolerant HBPummelo x Shekwasha with salt tolerant HBPummelo x Cleo) was successfully propagated by cuttings, and also introduced for TC propagation with Agromillora.  Both of these promising selections were also entered into the PTP. A few other promising ‘gauntlet’ rootstock genotypes were recovered by cutting off the top (scion portion) of field trees, as necessary for further propagation.  Propagation of recent PTP selections from the UF/CREC breeding program (past 3 years):  approximately 50 selections showing promise at fruit displays, etc. are now being propagated onto UFR-5 rootstock at Southern Citrus Nursery, 10 trees per selection (this includes all categories of fruit).   Tree Planting:  approximately 1000 trees of new hybrids were planted at the CREC and Riley Block (Haines City).  New grapefruit and pummelo clones in the PTP were planted at the Trailer Park block.  Approximately 200 additional rescued trees from the Balm/GREC were planted at the Eagle Lake Block; 500 trees of 6 scions on promising rootstock candidates were also planted at the Eagle Lake Block (part of the Tri-State project, not funded by CRDF).  The following trials were posted/updated (with new seasonal data) on our rootstock data website: Basinger ‘Vernia’ Rootstock Trial; Waverly Scion/Rootstock Trial; Indian River ‘Marsh’ Grapefruit Rootstock Trial; Indian River ‘Vernia’ Rootstock Trial; Water Conserve II Valencia & Midsweet Scion Trial; Post Office Rootstock Trial; Indian River Minneola Rootstock Trial; and St. Cloud OLL Clone/Rootstock Demonstration Planting.   The following trials have been updated and are awaiting final review for addition to the rootstock data website this quarter: Indian River Lemon Rootstock Trial; Peace River ‘Valencia’ rootstock Trial; SW Flatwoods Sweet Orange Rootstock Trial; Ver Beach Navel and Grapefruit Rootstock Trials; Charlotte County Multi-Scion rootstock Trial; LaBelle Valencia Advanced Production System (APS) Rootstock Trial; LaBelle Vernia rootstock Trial; South Ridge Valencia Rootstock Trial; St. Helena Rootsotck Survery Trial; and Teaching Block Scion and Rootstock Trial.              

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