Rootstock Options for the southern Sac Valley. Kat Pope Orchard Advisor, Sac-Solano-Yolo Feb 3 rd, PDF Free Download

Rootstock Options for the southern Sac Valley Kat Pope Orchard Advisor, Sac-Solano-Yolo Feb 3 rd, 2016

Talk outline What to look for in a rootstock Options for common Sac Valley limitations Anchorage Heavy Soils High ph B, Cl, Na

Top Three No perfect rootstock. Consider top limitations, make the rest work. Bigger isn t always better. Closer spacing can make up for less vigor. No 100% true rules of thumb for what rootstock type fits what limitation.

The Perfect Sac Valley Rootstock High early vigor Low later vigor Heavy soil/wet feet tolerance Gravelly soil tolerance Low suckering Compatibility with all cultivars Good anchorage Root disease resistance Nematode resistance Mid-to-high ph tolerance B, Cl, Na exclusion

The Perfect Sac Valley Rootstock

Rootstock selection: Figure out the biggest limitations of the site; find the rootstock to address those limitations. Remember, Some limitations are average conditions Some limitations are rare, but guaranteed eventually

Rootstock selection: Figure out the biggest limitations of the site; find the rootstock to address those limitations. Rootstock A Rootstock B Rootstock C Rootstock C Rootstock D Rootstock E

Rootstock selection: Figure out the biggest limitations of the site; find the rootstock to address those limitations. Rootstock A Rootstock B Rootstock C Rootstock D Rootstock E

Most common Sac Valley limitations Anchorage Heavy soils High ph B, Cl, Na Won t address nematodes, but certainly there are many options, dependent on which nematodes.

But What About Yield? Tighter spacing can often make up for smaller trees, so yield/acre stays high. Important to remember with rootstock trial results. Bigger isn t always better, if you lose other benefits.

Broadly speaking, Peach/Almond Hybrids High vigor Tolerant to high ph Tolerant to high boron, sodium, chloride Very good anchorage

Broadly speaking, Complex Hybrids High vigor More tolerant than peach to high ph More tolerant than peach to high boron, sodium, chloride Good anchorage

Broadly speaking, Peach-Plum Hybrids Moderate vigor More tolerant to heavy soils, wet feet Good anchorage

Anchorage Experimental Data Kern County. Planted 1997. March 4, 2001 80 mph winds for 5 hrs w/ 1.75 rain Rootstock Parents Kern Co Blow Over Bright s Hybrid PxA 13% Hansen 536 PxA 9% Hansen 2168 PxA 4% Viking Complex 4% Atlas Complex 30% Nemaguard Peach 58% Durham Blow Over Ishtara PxPlum 10% 47% Marianna Plum 0% Lovell Peach 0% 8% Krymsk 86 PxPlum 0% Durham Fumig t - Leaning

Anchorage Experimental Data Kern County. Planted 1997. March 4, 2001 80 mph winds for 5 hrs w/ 1.75 rain Rootstock Kern Co Blow Over Bright s Hybrid PxA 13% Hansen 536 PxA 9% Hansen 2168 PxA 4% Viking Complex 4% Atlas Complex 30% Nemaguard Peach 58% Durham Blow Over Ishtara PxPlum 10% 47% Marianna Plum 0% Lovell Peach 0% 8% Krymsk 86 PxPlum 0% Durham Fumig t - Leaning

*Normalized for trunk circumference Heavy Soils, High ph 5 th leaf, Durham. Farwell Loam soil 8 th leaf, Durham Rootstock Lbs/Tree Lbs/Tree Lovell 12.6 27.5 Atlas 18.2 38.0 Empyrean 1 19.3 Rootpac-R 13.7 Krymsk 86 13.5 Nickels 19.1 39.5 Viking 28.7 Bright s Hybrid 36.7 Hansen 536 44.3 Nemaguard 38.7

*Normalized for trunk circumference Heavy Soils, High ph Rootstock 5 th leaf, Durham. Farwell Loam soil 8 th leaf, Durham Lbs/Tree Trunk Circum Normalized Lbs/Tree Lbs/Tree Trunk Circum Normalized Lbs/Tree Lovell 12.6 50 13.9 27.5 68 31.6 Atlas 18.2 51 19.0 38.0 67 42.8 Empyrean 1 19.3 59 15.4 Rootpac-R 13.7 48 16.2 Krymsk 86 13.5 49 15.4 Nickels 19.1 57 16.4 39.5 76.8 34.9 Viking 28.7 69.5 31.3 Bright s Hybrid 36.7 73.9 35.0 Hansen 536 44.3 80.5 36.1 Nemaguard 38.7 72.4 38.4

Shallow Gravelly w/ Hardpan, Nickels Soils Lab Rootstock Lbs/Tree Trunk Circum Normalized Lbs/Tree Bright's Hybrid 25.7 67.4 25.8 Hansen 536 30.1 71.5 28.3 Nickels 29.5 76.9 25.1 Viking 22.2 65.8 23.1 Atlas 26.6 63.4 28.6 Nemaguard 24.5 64.5 26.0 Lovell 22.8 64 24.5

Shallow Gravelly w/ Hardpan Rootstock Lbs/Tree Trunk Circum Bright's Hybrid 25.7 Hansen 536 30.1 Nickels 29.5 Viking 22.2 Atlas 26.6 Nemaguard 24.5 Lovell 22.8 Normalized Lbs/Tree

Ion B, Cl & Na - Rootstocks Can Exclude Ions from Entering the Scion Tolerant rootstock Ion excluded by rootstock Sensitive rootstock Sensitive rootstock readily absorbs ion and transports it to the shoot

Keyes, 2014 Westley, 2014 Atwater, 2006 % Na % Cl % Cl % Na % Cl Nemaguard 0.88 0.27 0.27 0.64 0.22 Lovell 0.66 0.21 0.41 0.72 0.26 Atlas 0.58 0.28 0.19 Krymsk 86 0.55 0.32 0.41 Viking 0.21 0.12 0.22 Nickels 0.18 0.12 Empyrean 1 0.11 0.07 0.17 Hansen 0.11 0.09 0.17 0.17 0.09 Rootpac R 0.16 Bright s 5 0.15 0.20 0.07 F x A 0.13 Critical 0.25 0.3 0.3 0.25 0.3

Boron Rootstock Trial Yield Highly Correlated with Rootstock Lbs / Acre 2000 1800 1600 1400 1200 1000 800 600 400 200 0 a a a bc a ab a b b bc b bc b b c bc b c 2013 2014 2015 d c b d cd d Marvin silty clay loam Water: <1-3.1 mg/l B Soil: 1.3-2.2 mg/l B cv. Nonpareil Nursery grafted Planted: Feb, 2011 (Titan Apr 2011 not rep d) Spacing: 22 x 18 Different letters indicate statistical diff. values when compared in same year.

Boron Rootstock Trial Hull B Content Highly Correlated with Rootstock 2000 1800 1600 1400 c c ab a bc 2015 Hull_B_2014 c bc a 700 600 500 Lbs Per Acre 1200 1000 800 400 300 Hull B 600 200 400 200 100 0 Nickels Titan SG1 FxA Brights 5 Hansen Rootpac-R Viking Krymsk 86 Lovell 0

Boron Rootstock Trial Bloom Vigor Highly Correlated with Rootstock Bloom Vigor was rated (1-5 scale) based on flowers per unit canopy, not flowers in whole canopy. In other words, a large canopy didn t necessarily mean a higher bloom rating. Lbs Per Acre 2000 1800 1600 1400 1200 1000 800 600 400 200 a a ab ab 2015 Bloom 2015 bc bc c d 5 4.5 4 3.5 3 2.5 2 1.5 Bloom Rating 0 1 Bloom Vigor = 1 (Lovell) Bloom Vigor = 5 (Nickels)

Boron Rootstock Trial Canopy Size Highly Correlated with Rootstock Lbs Per Acre 2000 1800 1600 1400 1200 1000 800 600 400 200 a a b a c 75 2015 PAR 2015 70 cd cd d 65 60 55 50 45 40 35 % Canopy Light Interception 0 30

Are Higher Yields Just Result of Vigorous Rootstocks Larger Trees? No. True, larger trees higher yield (p < 0.001). PAR alone predicts 60% of the variability in yield. 2250 But, Hull B content explains 14% of the yield variability that PAR does not explain (p < 0.01) *. 2250 Worst combination is low vigor + high hull B: Lovell (& Krymsk) 80 700 2000 2000 70 600 Lbs Per Acre 1750 1500 1250 1000 750 500 250 45 50 55 60 65 70 75 80 % Light Interception (PAR Lbs Per Acre 1750 1500 1250 1000 750 500 250 350 450 550 650 Hull B (>300 ppm = toxicity ) % Light Interception 60 50 40 30 20 10 0 500 400 300 200 100 0 Hull B * R 2 contribution averaged over orderings among regressors. R relaimpo, lmg

Boron Rootstock Trial Summary (So Far) Poor Yield related to Canopy Size, Bloom Vigor, Hull Boron. Points to two potential rootstock effects: Vigorous rootstocks Larger Trees Boron tolerant rootstocks decrease B to scion Decrease B at growing points (flowers, nuts) where it can do damage. Nickels, Titan and FxA continue to perform better than other rootstocks under high boron conditions Lovell, Krymsk 86 continue to perform poorly under high boron conditions Looks like Lovell combines worst combination: Low vigor with high B

Rootstock Anchorage Heavy, High ph* Gravelly, Shallow Na/Cl Bright s - / / - / Nickels + / + + Titan F x A + + Atlas - + + - / Viking - - / / Hansen / + + + / Lovell / - - - - Krymsk 86 + / - - Rootpac R + *Only Marianna is resistant to + Phytophthora Root / Rot B /

Thanks! Questions?

Rootstock Options for the southern Sac Valley. Kat Pope Orchard Advisor, Sac-Solano-Yolo Feb 3 rd, 2016