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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Research Project #441451

Research Project: Advancing development of improved citrus scion cultivars

Location: Subtropical Insects and Horticulture Research

Project Number: 6034-21000-020-004-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Dec 10, 2021
End Date: Jun 30, 2024

Advancing development of improved citrus scion cultivars.

Hybridizations will focus on creating new hybrids that capitalize on advanced USHRL selections, focusing on HLB-tolerance. For some crosses Kishu-hybrids will be used as pollen parents to generate seedless progeny. Sweet orange-like, grapefruit-like, and diverse mandarin phenotypes are targeted. Germinate and grow new seeds of 700+ orange-like hybrids, and 200+ grapefruit-like hybrids 100+ mandarin hybrids, produced in 2021 crosses many of which will segregate for genetic seedless from using Kishu hybrids as pollen parents. One thousand priority populations from crosses in 2011-2016, will be assessed with deep phenotyping for HLB-tolerance metrics and fruit quality, to establish a foundation for genomic-based selection. We will evaluate 2019-planted hybrids to capitalize on citron- derived HLB-tolerance to introgress citron genetics into more sweet-orange-like hybrids and on a much smaller scale to develop Florida-adapted acid-fruits of commercial quality. Microcitrus hybrids will be evaluated for HLB- and ACP-tolerance, using a planting of diverse material now in its fifth year. The goal is to introgress Microcitrus-derived HLB-tolerance into standard market phenotypes especially sweet orange and grapefruit. Trees from irradiated buds of our most-grapefruit-like hybrid selections, showing some HLB-tolerance, are in field plantings and fruit will be assessed for low seed count and lycopene pigmentation. We have numerous trees from irradiated buds of ‘Jackson’ already in the ground, but a red ‘Jackson’ would be so valuable that we irradiated an additional 650 buds which created trees were field planted last year. Continue screening existing hybrids at both the Ft. Pierce and Leesburg Farms. There are >30,000 hybrids planted over the last few years from >550 unique parental combinations. Select buds of priority selections (irradiated and conventional hybrids) and pass through DPI's shoot-tip grafting program and establish material at the USDA Whitmore Farm as well as coordinating second tests in collaboration with NVDMC, FCPA and CRDF. Major replicated plantings of seedless/low seeded selections will be a focus. Coordinating with NVDMC, selections will be considered for early release to nurseries. To expedite identification of short-term HLB solutions, cultivars will be identified in collaboration with industry, for field evaluation of HLB-tolerance. The processing industry is working with us to identify potentially HLB-tolerant cultivars which may be combined to produce a satisfactory sweet-orange-like juice. In addition fresh fruit types will be identified.