GEM Avocados in New Zealand September 2019 Why GEM? 2 Seeka Grower - - PowerPoint PPT Presentation

GEM™ Avocados in New Zealand

September 2019

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Seeka Grower Roadshow | December 2016

Why GEM?

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Seeka Grower Roadshow | December 2016

Unlike other high value fruit crops (apples, kiwifruit, berries, nuts etc) average avocado yields are similar to those 20 years ago There are new innovations in growing systems and technology but these are only slowly being implemented Why? Avocados World Wide

An industry with only slow improvements in productivity

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Seeka Grower Roadshow | December 2016

Hass is a good variety for taste and shipping fruit Hass is high vigour and likes to alternate bear, tends to low yielding without significant management systems Best innovation to date has been high density planting, with Hass this is hard to do without Plant Growth Regulators and lots of pruning It would be great to have a variety with a growth habit that suits high density and has lower alternate bearing Avocado Industries are Largely Based on Hass

A good variety but it has limitations

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Seeka Grower Roadshow | December 2016

GEM has attracted attention as it:

▪ Has low vigour ▪ Compact growth habit ▪ Non-spreading ▪ Tolerates temperature extremes ▪ Very precocious ▪ Less alternate bearing ▪ Later maturity ▪ Very good taste ▪ Hangs late on the tree ▪ Attractive fruit

GEM Attributes

Positive characteristics for high density 16 year old tree

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Seeka Grower Roadshow | December 2016

GEM is grown through a licence with Westfalia Estates the world-wide master licence holder There is a very enthusiastic group of early adopter GEM growers in New Zealand Over 8,000 more trees will be planted in September to November 2019 Sounds impressive but area is small (53 acres) as the trees are planted at 160 per acre at 19.5’ by 13’ (400 per hectare at 6m x 4m spacing) GEM in NZ

8,500 trees planted in 14 orchards

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Seeka Grower Roadshow | December 2016

Seeking to understand how to best grow GEM to get high yields of high quality fruit Starting at the beginning of a new industry so I am using the new plantings to learn as much as we can I have a flowering and fruit set monitoring programme for GEM like I do for Hass Investigating different canopy management ideas, expect canopy management to change as the trees age Growing GEM

We need to learn how to grow GEM

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Seeka Grower Roadshow | December 2016

Planted trees from December 2017 to April 2018

Summer and Fall in New Zealand

The trees looked great…. …. to start with As time went by trees dropped leaves and started dying It was worse the later the trees were planted Trees on clonal rootstocks were the worst

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Seeka Grower Roadshow | December 2016

Tree Decline

Not typical of Hass, the roots were great Zutano 6 weeks after planting in March Dusa 6 weeks after planting in December Dusa several weeks after planting in March

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Seeka Grower Roadshow | December 2016

The tree decline was very unusual The trees died from the top down and had very strong and healthy roots Pruning the trees killed them Lots of bud break from above the graft forming new growth There was no disease or pest associated with the decline The trees were all from the same nursery Tree Decline

Some leaf drop and very heavy flowering was expected

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Seeka Grower Roadshow | December 2016

Tree Decline

Despite the leaf drop fruit set was OK

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Seeka Grower Roadshow | December 2016

Tree Decline

Despite the leaf drop fruit set was OK

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Seeka Grower Roadshow | December 2016

Tree Decline

New fruit had a red blush, too much sun?

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Seeka Grower Roadshow | December 2016

Tree Decline

Often new growth from above the graft

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Seeka Grower Roadshow | December 2016

Tree health survey, rating trees every few weeks Tracked rootstock and planting time Surveyed the growers for their management practices GPS mapped the location of every tree The worst affected trees were replaced the following spring at Seeka’s cost Tree Health Survey

Assessed every tree over time

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Seeka Grower Roadshow | December 2016

GEM Mapping

Individual trees GPS mapped after planting

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Seeka Grower Roadshow | December 2016

Tree Health Scale

1 = Dead to 10 = very healthy 2 3 5 7 10 10

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Seeka Grower Roadshow | December 2016

GEM Mapping

Individual trees health rating

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Seeka Grower Roadshow | December 2016

GEM Mapping

Individual trees health rating

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Seeka Grower Roadshow | December 2016

Planting Time and Rootstock

Tree mortality Planting time Dusa Bounty Zutano

December 2017 26.0% - overwatered 4.8% 4.0% February 2018 24.6% 15.6% March 2018 16.4% 11.6% 54.3% 6.0% 2.4% 1.3% April 2018 5.5% 78.5% - end of April 19.4% 0.0% October 2018 2.8% No of trees 3263 491 1219

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Seeka Grower Roadshow | December 2016

Death followed leaf drop and excessive flowering in spring Would normally assume it was a root health problem This was wrong as the roots were healthy but….The root ball was smaller the later the planting

▪ December roots extended 1-2m (39” – 78”) ▪ February roots extended 1m (39”) ▪ March roots extended 0.5m (19.5”) ▪ April just past the root ball

Healthy trees had a red flush while sick trees had a green flush suggesting nutrients were an issue Tree mortality was mostly on the Dusa rootstock Thickening/expansion of the trunk was a good sign the tree would survive no matter how bad the top looked

Planting Time and Rootstock

Observations

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Seeka Grower Roadshow | December 2016

Dusa is a high vigour rootstock GEM is a low vigour scion with high precocity Contrast with Hass a high vigour scion Bounty and Zutano are moderate vigour rootstocks Dusa has “grabbed” the carbohydrate and is using it for growth at the expense of the GEM flowers Effectively starving the GEM part of the tree as if the roots were damaged Hence the same symptoms as Hass trees that lose their roots Tree Mortality

Speculation on what happened

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Seeka Grower Roadshow | December 2016

Plant Dusa rootstock October to December Plant Bounty and Zutano in spring and fall Be very careful not to overwater Apply foliar fertiliser every two weeks even in winter For excessively flowering trees remove flowers August/September, try and keep the vegetative bud Don’t prune trees Drench the soil around struggling trees with phosphorus acid Planting Time and Rootstock

Conclusions

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Seeka Grower Roadshow | December 2016

Foliar Fertiliser

Nitrosol NPK (8:3:6)

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Seeka Grower Roadshow | December 2016

Foliar Fertiliser

Nutrikelp Plus

This didn’t work very well Need to figure out the best foliar option by trial and error

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Seeka Grower Roadshow | December 2016

Solid Fertiliser

Young Trees AvoMix a blended granular fertiliser

Applied at a small handful a tree monthly

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Seeka Grower Roadshow | December 2016

So far little difference to Hass Expecting to run GEM at higher Nitrogen than Hass GEM Leaf Nutrient Levels

Comparison with Hass Nutrient GEM Hass Nitrogen 2.6 2.4 Phosphorus 0.17 0.14 Potassium 1.2 1.1 % Calcium 1.4 1.4 Magnesium 0.29 0.37 Sulphur 0.23 0.24 Zinc 32 35 Boron 29 35 ppm Copper 10 43 Manganese 207 127 Iron 44 50

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Seeka Grower Roadshow | December 2016

Quality issues

Fruit scarring

Two causes: Greenhouse Thrips and wind rub The skin is very sensitive when the fruit are young Good shelter is essential

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Seeka Grower Roadshow | December 2016

About one month later than Hass avocados However…… Seed coats were only fully mature in November Suggests harvest could start October/November for New Zealand grown GEM™ avocados Maturity as defined by Dry Matter

GEM

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Seeka Grower Roadshow | December 2016

Maturity as defined by Dry Matter

Average Dry Matter by Date Across Four Seasons

Table 1. Average dry matter for 20 fruit samples collected from the GEM™ avocado trees in the Te Puke geneblock. Values are from the NZ Avocado Annual Research Report 2008 and Seeka measurements. Date Average DM (%) Seed coat % fully mature Average Fruit weight (g) 10/10/2006 28.9 233.2 12/1/2007 37.5 263.6 8/11/2007 31.9 243.8 20/11/2007 33.9 256.3 4/12/2007 34.6 235.7 18/12/2007 34.0 242.6 8/1/2008 37.7 253.2 25/9/2008 27.0 259.1 28/10/2008 29.5 273.3 31/10/2016 29.4 10 240.7 30/11/2016 34.2 100 261.4 9/1/2017 37.6 100 256.2

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Seeka Grower Roadshow | December 2016

Maturity as defined by Dry Matter

2019 results

Youngest trees have the earliest DM Library tray trial underway to define the DM standard for GEM in NZ

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Seeka Grower Roadshow | December 2016

Tree Spacing

19.5’ x 6.5’ (left) vs 19.5’ x 13’ (right)

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Seeka Grower Roadshow | December 2016

Tree Structures

Berms and post and wire

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Seeka Grower Roadshow | December 2016

Tree Structures

Post and wire with strainer post

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Seeka Grower Roadshow | December 2016

Tree Structures

Post and wire no need for a strainer post

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Seeka Grower Roadshow | December 2016

GEM Tree Monitoring

Mark three shoots on each of 20 trees

Follow flower bud break and development Timing of ovule initiation, flowering start, duration of flowering, fruit set Monitor the variability in phenology to make better management decisions Evaluate different flush types for fruit set success

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Seeka Grower Roadshow | December 2016

GEM Tree Monitoring

Budbreak visual scale

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Seeka Grower Roadshow | December 2016

GEM Tree Monitoring

More vegetative shoots in the second spring

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Seeka Grower Roadshow | December 2016

GEM Research

Future projects

Berms or flat land planting

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Seeka Grower Roadshow | December 2016

GEM Research

Future projects

Cages or exposed

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Seeka Grower Roadshow | December 2016

GEM Research

Future projects

Tree pruning ideas Borrow from high intensity apples Droopy growth habit, keep light onto the productive areas and maintain replacement flowering wood Easier to show than describe

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Seeka Grower Roadshow | December 2016

GEM Tree Monitoring

More vegetative shoots in the second spring