Emerging Technologies

Transcription

1 Vegetable Grafting Propagation Emerging Technologies Chieri Kubota, Leo Sabatino, and Mark Kroggel The University of Arizona Tucson, AZ, USA

2 Emerging Technologies in Grafting Propagation Unrooted grafted cuttings Short term storage of grafted seedlings (Poster by Hans Spalholz) Indoor production system under artificial lighting for scion/rootstock plant production

3 Use of unrooted grafted cuttings Unrooted grafted cuttings are used in Japan and Israel Could be used effectively in the US with necessary modifications (longer transportation, limited capital input for 2nd propagators) Preliminary study at UA showed that the harvesting timing and transportation conditions affected posttransportation performance of unrooted grafted cuttings of tomato.

4 Unrooted grafted cuttings Primary nursery to produce grafted plants Harvested unrooted grafted cuttings to ship Local/secondary nursery to root and grow on the cuttings to finish

5 Unrooted grafted cuttings: our study objectives Two major questions: For long distance transportation, when is the best timing to harvest grafted cuttings to ship them? Would refrigeration be necessary for transportation of grafted cuttings? (i.e., watermelon is sensitive to low temperature)

6 Materials and Methods Plant materials Tri-X-313 watermelon Strong Tosa interspecific squash rootstock Grafting method: single-cotyledon method Grafted cuttings harvested before, during or after healing Temperature-controlled chamber for simulating shipping (3 days). Repeated three times

7 Methods Healing conditions (7 days): 24 hours in dark, then illumination 1-5th days at 29 C; ~100% RH 6-7th days at 29 C; lowering RH Grafting Scion: Tri-X-313 Rootstock: Strong Tosa Harvesting after 0, 1, 3, 5, or 7 days of healing Harvesting grafted cuttings Sticking cuttings in soilless substrate to root under high RH and % shading Placing cuttings at 12 or 20 C for 3 days for Simulated shipping conditions

8 Grafted seedlings 12 days after removal from the shipping treatment (12 DAT) 12 C shipping temperature 20 C shipping temperature

9 Grafted seedling growth as affected by the harvest timing of grafted cuttings (12 DAT) Days in healing to harvest Percent rooting in GH DW (g) Epicotyl (mm) # Leaves NS 0.23 ** 10.7** 2.2** NS 0.21 NS 7.0** 2.1** NS 0.23 * 12.0* 2.9** NS 0.18 NS 17.2 NS 3.3 NS NS 0.18 NS 24.4 NS 3.7 NS Untreated control

10 Conclusions grafted cuttings A minimum of 5 days in healing are recommended to harvest grafted watermelon cuttings. [2 days longer than what was recommended for tomato] Packing considerations are use of coolant and good insulation to avoid temperature rise during shipping. [too low temperature will be also problematic] Shipping trials are planned in 2013 (multiple seasons).

11 Short term storage of grafted seedlings Increases the production capacity without increasing labor input. Adds more flexibility in propagation schedule. Currently species/cultivar specific responses to short term low temperature exposure are being investigated for cucurbits and solanaceous species (Spalholz & Kubota; poster). Before storage After 4 weeks at 9C

12 Indoor production system of grafted seedlings

13 Advantages/values of indoor plant production Uniform & vigorous growth with high density Controlled flower bud development (for tomato) High level of hygiene (limited access for arthropod vectors) No pesticide High water-, space-, fertilizer- use efficiencies (e.g., 90% or more water can be recycled through condensation recovery) Consistency suitable for scheduling and automation

14 A commercial nursery of 15 million grafts per year using indoor systems (Ehime, Japan) Air shower for the facility entrance Lighting system CO 2 injection Nutrient delivery Sensors Air flow fans Insulation and containment A/C unit & fan Key components of indoor transplant production

15 Electricity cost per scion and rootstock seedlings in Japan Transplants Cells per tray Production in days Cost (JPY) (/seedling) [1 yen = 1.2 cents US] Tomato (scion/rootstock) yen ($0.009) Tomato (scion/rootstock) yen ($0.006) Cucumber Scion yen ($0.004) Cucumber stock yen ($0.006) Data obtained by Taiyo Kogyo, Co. Slide by T. Kozai

16 Ultra-high water use efficiency 90% or more water can be recycled. This can be a promotional aspect of seedling production in areas with limited water resource. (Ohyama et al, 2002)

17 Introducing high tech or staying with low tech? Using high tech (capital and logistics intensive model), producing greater number of high quality seedlings with lower costs Using low tech (capital limited model), producing large amount of seedlings with conventional costs Goal is to produce and distribute large numbers of plants at affordable costs.

18 Acknowledgements UA SCRI grafting team (Myles Lewis, Young Jun Son, Russell Tronstad) Kubota Lab members Dr. Toyoki Kozai, Chiba University USDA SCRI UA CEAC Syngenta Seeds Veg Grafting Information Website: cals.arizona.edu/grafting Greensys 2011, Greece