The U.S. Department of Agriculture (USDA) citrus scion breeding program is urgently working to develop HLB-tolerant cultivars with excellent fruit quality and productivity when HLB-affected. The slow process of assessing new citrus hybrids is a major impediment to delivery of these much-needed cultivars. We generate thousands of hybrids each year, germinate the seedlings, grow them for 2 years in the greenhouse, plant them at high density in an HLB-endemic field (0.76 m in-row spacing), grow them for 5 to 10 years, and make selections based on tree performance and fruit quality of these HLB-affected trees. Based on promising reports of accelerated citrus growth when grown in an MRM system (Adair, 2018), we tested the hypothesis that such a system may accelerate growth and selection of new hybrid seedlings.
Adair, R.C. Jr 2018 Metallized reflective mulch: More fruit with less psyllids Researchgate pdf of presentation. 1 Dec. 2021. <https://www.researchgate.net/publication/324174438_Metalized_Reflective_Mulch_More_Fruit_with_Less_Psyllids>
Stover, E., Gmitter, F.G. Jr., Grosser, J., Baldwin, E., Wu, G.A., Bai, J., Wang, Y., Chaires, P. & Motamayor, J.C. 2020 Rationale for reconsidering current regulations restricting use of hybrids in orange juice Hort. Res. 7 38 https://doi.org/10.1038/s41438-020-0277-5
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