- Author: Ben Faber
A recent University of Florida-Institute of Food and Agriculture Sciences (UF-IFAS) blog has a review of the last 60 years of rootstock trials and the lessons learned from those trials. It also has links to the results of those trials and a summary of the results of those trials.
What's also interesting is the “Expert System” that can be used to select a rootstock based on the horticultural traits (height, fruit size, etc), soil properties (pH, salinity, wetness, etc) and/or disease resistance.
The data is based on 21 characteristics of 48 rootstocks. It encompasses both the UF and USDA rootstock trials in Florida. And this last word is a key to all the data. It's based on the Florida condition and on many rootstocks that have not be trialed in California and aren't available commercially here. It is, however, a wonderful resource (Bibliography also included), learning tool and good starting point for reviewing potential rootstocks before ordering trees and planting an orchard. It's best to learn of potential problems before planting than having to learn how to correct those problems once the trees are in the ground.
And here is more from the USDA on citrus rootstocks: https://citrusrootstocks.org/
For an overview of California rootstocks for lemon, check out the presentations here
- Author: Ben Faber
On Thursday, October 17, 2019 the University of California Cooperative Extension (UCCE) held a Lemon Rootstock and Scion workshop and field tour in Santa Paula, California. Results from Citrus Research Board (CRB) sponsored field trials evaluating several lemon rootstocks and scions were highlighted at this meeting. This event was well attended by over 100 grove managers, citrus growers and industry representatives. Speakers included CRB-funded researchers Ashraf El-kereamy, Ph.D., Mikeal Roose, Ph.D., Tracy Kahn, Ph.D., and Glenn Wright, Ph.D. The CRB has been funding research on several single site and multi-location lemon field trials, some of which have been ongoing since the late 1980's. Mikeal Roose, Tracy Kahn and Glenn Wright provided updates on the results of previous rootstock trials and the multi-location lemon rootstock and scion trials at Santa Paula, Lindcove Research and Extension Center and desert locations. Attendees learned about the various yield, packout and fruit quality of several lemon selections being studied in addition to new, non-lemon citrus cultivars to be released in the coming years. Following the presentations, attendees were invited to visit one of the lemon rootstock field trials.
Limoneira Company has been extremely helpful in much of this lemon research over the years. We thank them and also the Master Gardeners who helped in organizing the event held at the Limoneira meeting center. Read about a sideline at the event HERE.
Presentations from the workshop are available on the UCCE Ventura website HERE.
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- Author: Ben Faber
Lemon Scions and Lemon Rootstocks Workshop & Field Tour
October 17, 2019
8:00am-12:00 PM
Visitors Center, Limoneira Co., 1141 Cummings Rd, Santa Paula, CA 93060 View map/directions here
Contact: Ben Faber, 805-645-1462, bafaber@ucanr.edu
Which Way Lemon Industry?
What are Lemon Rootstock Choices?
What are Lemon Scion Choices?
How are they Complementary?
What are their Effects on Yield? Fruit Quality? Canopy Growth? Soil Compatibility? Tree Health?
HLB Tolerance? Maybe We Know a Little.
How do Scions and Rootstocks Compare in the Desert, Valley and Coast?
Come Learn this and more. Tour a Scion/Rootstock Trial
Speakers:
Mike Roose, UC Riverside Citrus Breeder
Tracy Kahn, UC Riverside Curator Citrus Collection
Glenn Wright, University of Arizona Citrus Extension Specialist
Ashraf El-Kereamy, UC Riverside Citrus Specialist
- Author: Ben Faber
When avocados are converted from one variety to another or in the case of severe frost or fire damage and there is still a healthy root system, sucker grafting should be considered. This can lead to more rapid production and is one of the easiest, most successful grafting procedures. It does take considerable attention to the graft and protection from damage by animals and overgrowth from competing suckers.
A detailed presentation of the process is found in a UC publication – Propagating Avocados, authored by Bob Whitsell, Grey Martin, BOB Bergh, Alvin Lypps and Hank Brokaw. This pamphlet was published in 1989 and is still the bible of avocado propagation. It mentions the use of parafilm as a wrapping material. It is now the standard for grafting and budding. Parafilm has pretty much replaced polyvinyl tape and asphalt emulsion for sealing and attaching the scions. It is a strong material, yet readily stretches to allow for bud growth. Where the grafts are exposed to the sun, this tape should also be painted white to protect the growing point from sunburn.
http://www.avocadosource.com/papers/research_articles/whitsellrh1989.pdf
And an older publication by E.O. Stromberg
http://www.avocadosource.com/CAS_Yearbooks/CAS_25_1940/CAS_1940_PG_89-91.pdf
- Author: Ben Faber
Citrus is a messy botany. It loves to cross with anything and in so doing creates very complex ancestry. C-35 rootstock is a citrange and was created for its tolerance to cold, but is also good in Phytophthora situations and creates a slightly smaller tree. Oddly, it is deciduous, a cross between Poncirus and Citrus. It's a trifoliate hybrid. 'Meyer' lemon is the same mess, a cross between a lemon and an orange/mandarin. You would think these two messed up cousins might do well, but in several instances there is an incompatibility. 'Meyer' has been grown successfully on 'Macrophylla' and 'Yuma Ponderosa', both of which are also complex hybrids.