Using Vaccinium arboreum (sparkleberry) to increase soil adaptation and mechanical harvest efficiency of blueberry Rebecca Darnell Horticultural Sciences Department University of Florida Gainesville, FL Blueberry industry in FL • Southern highbush blueberry • Based on V. corymbosum • Hybrids with wild species native to the southeastern U.S. • V. elliottii / V. darrowii / V. virgatum UF breeding program Jim Olmstead • Flavor • Crisp texture • Winter chilling requirement • Soil adaptation • Mechanical harvesting Soil adaptation Blueberry soils Mineral soils • Acidic • pH>6.0 • High organic • Low organic matter matter • Accumulate NO3 • NH4 over NH4 Photos: J. Williamson/J. Olmstead NH4 NO3 Most FL soils require amendments to be suitable for crop production Photo: J. Williamson Bark beds Bark incorporated into soil Incorporated bark with ground cloth Pine bark increases organic matter, decreases soil pH, maintains N in NH4 form Greatly increases establishment costs of SHB planting in Florida Photos: J. Williamson Q1. Are there Vaccinium species native to higher pH (nitrate predominant N form), low om soils, where amendments wouldn’t be needed? UF breeding program Mechanical harvesting Mechanical harvesting Photo: J. Williamson Harvesting Hand-harvested – Expensive – Labor intensive – Low availability Q2. Are there Vaccinium species that have an architecture more adaptable to mechanical harvesting? Vaccinium arboreum “Sparkleberry” • Native to the southeastern US • Tree-like growth habit • Deep root system – drought tolerant • Tolerates low organic matter soil, pH up to 6.5 • N primarily in NO3 form N uptake in sparkleberry vs blueberry 0.30 sparkleberry 0.25 blueberry 0.20 /plant/day) 0.15 mmol 0.10 0.05 N uptakeN ( 0.00 NH4 NO3 Nitrate reduction in sparkleberry vs blueberry 600 sparkleberry blueberry /g FW/h) 400 nmol 200 NR activity ( activity NR 0 NH4 NO3 NO3 uptake and assimilation in sparkleberry is greater than in blueberry Can we use sparkleberry to increase adaptation of blueberry to more mineral soils? Sparkleberry has a tree-like architecture And increase mechanical harvesting potential? Grafted vs Own-rooted Pine bark amended vs non-amended soil Meadowlark & Farthing grafted Summer 2010. Field planted May 2011 2-yr-old ‘Meadowlark’ SHB Grafted Own-rooted Leaf nutrient concentration – Summer 2012 N* P K Mg Ca B Fe* Cultivar Trt % % % % % ppm ppm M’lark Own/Soil 1.56 0.10 a 0.57 0.14 0.66 49.17 ab 51.00 Own/Bark 1.50 0.09 b 0.49 0.15 0.72 58.83 a 47.50 Graft/Soil 1.49 0.10 a 0.56 0.15 0.67 45.67 b 48.00 Graft/Bark 1.52 0.10 a 0.55 0.14 0.69 48.17 ab 45.17 Farthing Own/Soil 1.61 0.09 0.52 0.16 0.72 50.50 a 48.83 Own/Bark 1.57 0.09 0.52 0.16 0.73 45.17 b 48.83 Graft/Soil 1.67 0.10 0.56 0.15 0.71 48.33 ab 49.17 Graft/Bark 1.64 0.10 0.57 0.15 0.69 49.83 a 48.67 Sufficiency ranges: 1.7-2.0 0.10-0.40 0.41-0.70 0.13-0.25 0.41-0.80 31-80 61-200 (Hart et al., 2006) % % % % % ppm ppm Flower buds/shoot - 2013 6 a 5 a a a ab a 4 b b 3 2 Flower Flower cm buds/15 shoot 1 0 Own/Soil Own/Bark Graft/Soil Graft/Bark Own/Soil Own/Bark Graft/Soil Graft/Bark Farthing Meadowlark Bloom progression in ‘Farthing’ - 2013 100 90 80 70 60 50 Own/Soil 40 Own/Bark Bloom (%) Bloom 30 Grafted/Soil 20 Grafted/Bark 10 0 Jan-13 Feb-13 Feb-13 Feb-13 Mar-13 Mar-13 Mar-13 Date Bloom period averaged 7 days shorter in grafted compared with own-rooted ‘Farthing’ Bloom progression in ‘Meadowlark’ - 2013 100 95 90 85 Own/Soil 80 Own/Bark 75 Bloom (%) Bloom Grafted/Soil 70 Grafted/Bark 65 60 Jan-13 Feb-13 Feb-13 Feb-13 Mar-13 Mar-13 Mar-13 Date …and in ‘Meadowlark’ 3000 a 2500 2000 b b 1500 b 1000 Total yield (g) yield Total 500 0 Own/Soil Own/Bark Grafted/Soil Grafted/Bark 3000 a 2500 2000 b b 1500 b 1000 Total yield (g)yield Total 500 0 Own/Soil Own/Bark Grafted/Soil Grafted/Bark Flower buds/shoot Flower Canopy volume Own/Soil Own/Bark Graft/Soil Graft/Bark Own/Soil Own/Bark Graft/Soil Graft/Bark • Yields in mature plantings? Photo: J.Spiers • Mechanical harvest ability? • Postharvest fruit quality? Blueberry Trees? .