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

Transcription

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

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

3 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.

4 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

5 The Perfect Sac Valley Rootstock

6 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

7 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

8 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

9 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.

10 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.

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

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

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

14 Anchorage Experimental Data Kern County. Planted March 4, 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

15 Anchorage Experimental Data Kern County. Planted March 4, 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

16 *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 Atlas Empyrean Rootpac-R 13.7 Krymsk Nickels Viking 28.7 Bright s Hybrid 36.7 Hansen Nemaguard 38.7

17 *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 Atlas Empyrean Rootpac-R Krymsk Nickels Viking Bright s Hybrid Hansen Nemaguard

18 *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 Atlas Empyrean Rootpac-R Krymsk Nickels Viking Bright s Hybrid Hansen Nemaguard

19 Shallow Gravelly w/ Hardpan, Nickels Soils Lab Rootstock Lbs/Tree Trunk Circum Normalized Lbs/Tree Bright's Hybrid Hansen Nickels Viking Atlas Nemaguard Lovell

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

21 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

22 Keyes, 2014 Westley, 2014 Atwater, 2006 % Na % Cl % Cl % Na % Cl Nemaguard Lovell Atlas Krymsk Viking Nickels Empyrean Hansen Rootpac R 0.16 Bright s F x A 0.13 Critical

23 Boron Rootstock Trial Yield Highly Correlated with Rootstock Lbs / Acre a a a bc a ab a b b bc b bc b b c bc b c d c b d cd d Marvin silty clay loam Water: <1-3.1 mg/l B Soil: 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.

24 Boron Rootstock Trial Hull B Content Highly Correlated with Rootstock c c ab a bc 2015 Hull_B_2014 c bc a Lbs Per Acre Hull B Nickels Titan SG1 FxA Brights 5 Hansen Rootpac-R Viking Krymsk 86 Lovell 0

25 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 a a ab ab 2015 Bloom 2015 bc bc c d Bloom Rating 0 1 Bloom Vigor = 1 (Lovell) Bloom Vigor = 5 (Nickels)

26 Boron Rootstock Trial Canopy Size Highly Correlated with Rootstock Lbs Per Acre a a b a c PAR cd cd d % Canopy Light Interception 0 30

27 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 But, Hull B content explains 14% of the yield variability that PAR does not explain (p < 0.01) * Worst combination is low vigor + high hull B: Lovell (& Krymsk) Lbs Per Acre % Light Interception (PAR Lbs Per Acre Hull B (>300 ppm = toxicity ) % Light Interception Hull B * R 2 contribution averaged over orderings among regressors. R relaimpo, lmg

28 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

29 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 /

30 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.

31 Thanks! Questions?