usda citrus rootstocks for commercial use · usda citrus rootstocks for commercial use dr. greg...
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USDA Citrus Rootstocks for Commercial Use
Dr. Greg McCollum
USDA, ARS
Kim D. BowmanResearch Geneticist
USDA, ARS, Ft. Pierce
Dr. Ute Albrecht
UF/IFAS, SWFREC
Florida and California Industry and Federal Support
CRDF GrantsFlorida Citrus Research Foundation
HLB-MAC GrantsNIFA SCRI Grants
CRB Grants
FDACS - DPIGrower-Cooperators
Approaches Sexual hybridization using elite resistant and
tolerant parents to develop superior rootstocks
Study gene expression and metabolism with HLB and tolerant germplasm to guide development of tolerant cultivars
Develop propagation methods and horticultural treatments relevant to use of new rootstocks
Greenhouse and long-term field testing of rootstock germplasm
Release superior new rootstock cultivars 13 new rootstocks released from 2001-2018
Impact: Florida FDACS Report July-Nov 2018
Rootstock Total propagations1 US-942 323,6512 Kuharske 203,0493 X-639 160,8924 Sour orange 147,2755 Swingle 103,1836 US-802 65,0267 Volkamer 63,2908 US-812 38,6009 US-897 28,01110 UFR-04 13,44511 Carrizo 12,44012 C-35 8,128
Every field trial is a source of unique information about rootstock performance
under those specific conditions
By putting together information from multiple trials in different locations,
we can make good inferences of broad field performance
Lake WalesPolk County
Lake Wales, Polk County Trees planted 2008 Valencia scion 21 trees per rootstock 7 Replicates; Randomized 100% infected with CLas
USDA-WheelerCooperative Valencia Trial
USDA –Wheeler Rootstock TrialValencia scion Polk County
Rootstock 2012 2013 2014 2015 Total lbs/treeUS-942 95 148 146 115 500US-1516 71 132 119 143 465US-896 79 141 134 97 452US-1503 64 104 132 134 434Swingle 60 104 110 123 397US-802 60 130 104 95 388Kuharske 71 99 104 93 366US-812 77 104 77 97 357Cleopatra 35 75 112 126 348Kinkoji 42 86 84 75 287
USDA-Wheeler Valencia Trial Yields
Silver Strand Grove, Collier County
Valencia Scion; Trees planted 2002 18 trees per rootstock 6 Replicates; Randomized 100% infected with CLas
USDA-Barron Collier Cooperative Valencia Trial
Rootstock 2010 2012 2013 2016 Total lbs/tree
US-802 182 151 222 210 765 a
US-942 130 152 181 154 616 b
Cleopatra 130 123 182 166 599 b
Carrizo 114 114 170 154 551 b
Swingle 128 124 138 155 544 b
US-812 143 92 146 143 523 b
US-897 93 56 112 71 332 c
USDA-Barron Collier Valencia Trial Yields
Rootstocks also affect:• Tree size• Fruit size• Fruit brix and acid• Fruit drop• Shoot flush• Root flush• Canopy decline• Las titer
Rootstock
Planting
arrangement
Number trees
planted
Number trees died
Percent tree death
US-897 6 x 112 672 12 1.8 b
US-812 6 x 76 456 12 2.6 b
US-852 6 x 76 456 14 3.1 b
Swingle 6 x 76 456 16 3.5 b
US-942 6 x 112 672 24 3.6 b
x-639 6 x 76 456 23 5.0 b
Sour orange 6 x 76 456 48 10.5 a
USDA-Hammond Ray Ruby rootstock trial, Indian River County
USDA- Hammond Rootstock TrialRay Ruby scion Indian River County
Harvest1 2 3 4 5 6 7 8
Tota
l sol
uble
sol
ids
7.5
8.0
8.5
9.0
9.5 639812852897942SOSW
Ray Ruby rootstock trial, Indian River County8 sampling times (Sept. May)
X639
Sour
US-942
Main effects of rootstock on Ray Ruby juice quality in January (2011-14)
Other trials
Lake WalesPolk County
ImmokaleeCollier County
USDA Rootstock Field Trials
Lake WalesPolk County
ImmokaleeCollier County
B1B2
B3
B5
B6B10
B4
B9B14
B19
B13B15
B18B21
B22B23
B24
B7B8
B11B12
B16B17
B20
MB1
MB2
T1
P1MA1
MA2MA3
MA4MA5
B28
B26
B25
B27
Bingo Rootstock Trial at Whitmore FarmPlanted 2018
Sugar Belle Rootstock Trial at Whitmore FarmPlanted 2018
In Bingo trials comparing rootstock effects on scion dieback
Rootstock
# branches with dieback per rep @
1 month
Total length dieback per rep (cm) @ 1 month
Older Carrizo 2.50 a 23 aCleo 0.57 b 6 bSour 0.43 b 2 bYamaguchi 0.33 b 2 bRidge 0.29 b 3 bSwingle 0.29 b 3 bUS-942 0.29 b 1 bUS-896 0.14 b 1 bCarrizo 0.14 b 0 bUS-897 0.00 b 0 bFlying Dragon 0.00 b 0 bUS-852 0.00 b 0 bUS-812 0.00 b 0 bUS-802 0.00 b 0 bUS-1516 0.00 b 0 b
St Lucie County Valencia Scion; Trees planted 2014 50 rootstocks; 12 Replicates;
Randomized 90% infected with CLas
USDA Picos Farm Valencia Trial –SuperSour rootstocks
Contains 45 hybrids; and Sour orange, Swingle, Cleopatra
S upersour
USDA Rootstock Trial B14eValencia scion St. Lucie County
Three new rootstocks released2018
Parentage of Sour orange isCitrus grandis x Citrus reticulata
USDA rootstocks are categorized as SuperSour when parentage includes Sour orange
orCitrus grandis and Citrus reticulata
Named SuperSours
SS1, SS2, SS3 will need to be propagated by cuttings or tissue culture, initially
Seed trees have been planted for all three.
First seed harvested for SS1 fall 2018.
If seedlings determined to be suitably uniform, seed distribution can start in 2019.
For future, large scale use of newest rootstocks will have to use tissue culture because of long delay in having enough seed.
Cutting Tissue cultureSeed
Greenhouse studies
Field trial - SWFREC
Oct 2017
Field trial - Hendry County
April 2018
Field trial - Polk County
April 2018