Walnut Flashcards
scientific Name
Family
Origin
highest producer
Juglans regia
Juglandeceae
Persia
China
Walnut
Nutritional Value
fat fiber carbonhydrate protein mineral water it reduces bas cholesterol andrisk of heart disease walnut oil vit C.B1,B2,B5,B6
effect of non ideal climatic coonditions
cannot tolerate very high or low, temperature and strong winds
greater damage occurs when the temperature is 42 celsuis
can tolerate average temperature upto -10 c
High summer temperature causes damage to the fruit and may result in the shrinking of nuts.
Small damage can occur roughly at 100F (380C)
Climatic requirement
adapted cold temperature optimum temperature 7-21 C annual rainfall-800 mm/year timing of rainfall id the key Altitude: 1300- 2500 masl( above 2500 avoid commercial prodn-due to erratic and total crop loss of late spring frost)
pH: 5.5 – 6.5
Timing of rainfall is the key
Spring rainfall = walnut blight
Harvest rainfall = Nut staining & rots.
Temperature in Bhutan
Cool period in Autumn (to promote leaf fall &physiological process of hardening)
Not recommended in areas of late spring & early fall frost (as freezing temp kills growing point)
Temp >38oC result sun burning of hulls & shriveled kernal
Topography
Gentle slopes – manages easily
Choose a site with southerly & south westerly facing ( warms up faster in spring & cools down more slowing in Autumn thus extending the growing season at higher altitude)
Avoid northerly & easterly aspects
Choose a site with good frost drainage
Plant characteristics
Flowers
Large deciduous tree: =20-30m Tall Sexuality Monoecious; Displays dichogamy Female flowers – Pistillate Male flowers – Catkins
Pollinizers
Soil
Placed in permanent position in the orchard
- Placed every eighth row, perpendicular to the wind direction (90o angle)
Soil should allow root penetration of 3-4m.
Free of impermeable layer
deep, friable loamy soil
Free from a fluctuating water table.
Slightly acidic soil pH 5.5-6.5
Select sites with proper drainage
- A few hours of water-logging can cause servere damage
Variety selection
Market requirement
- Chilling requirement
- Time of leafing & bloom (bud break).
- Lateral bud fruitfulness
Varieties in Bhutan
Kanthel selection big and long trapezoid nuts semi erect and vigorous regular bearer thin shelled flowering habit; female flowering first leafing out in first week of april Disease : tip die back Nut size : 4.27 mm Kernal weight: 9.32 g Harvesting in end of sept under Yusipang Yusipang 2 Nut sie: 4 mm Nut weight : 20.75 g Kernal wt : 8.3 g Harvesting in ed of sept under Yusipang condition
Rootstocks
Juglans regia seedlings
Available from Druk Seed & RNR Research Centers.
Vigorous, fruits 6-8 years after planting.
Juglans nigra
less vigorous, suitable for high density planting.
Trees fruit in 5-6 years after planting.
Propagation
Sexual propagation-used only for rootstock
Planting seeds in nurseries in the fall allows for the necessary stratification
If planted in the spring stratify for at least two months to ensure germination.
Vegetative Propagation
Vegetative propagation ( whip grafting & patch budding)
Hot callusing
callusing types
A method use in difficult to propagate species to expose the grafted tree to controlled temp & humidity regimes.
The graft union exposed to elevated temp for pre-determined period to accelerate cell division
It responds by forming new callus tissue ,1st imp step in callus bridge formation between scion and rootstock in success
Temperature inside heated room at 25 to 28°C & RH of 80-90%.
Moist sawdust in room heated to26°C with RH of 70-90%
Heated greenhouses
Hot callus pipe
Intercultural operations
training
Pruning
Centre leader or, Modified Centre Leader system
Carried out in the dormant season but early spring is preferable.
Young trees (16-17yrs) & middle aged (34-35yrs) cut back to 3yr old wood.
5.5% - 6.5% more buds for budding
Mature trees (40 yrs old) cut back to 4-5yr wood
Control tree size Maintain vigour & fruitfulness on spurs Renew wood Remove weak, dead, interfering branches Facilitate cultural operations
Fertilizer & manure
Irrigation
First few years give small amounts of K and P. Fifth year to full production,60 – 100 kg/ha of K 40 – 80 kg/ha of P Apply N 100g/tree & increase by 100g every year. Irrigation Most important June-September Coincides with the monsoon Weed control, in young trees, promotes good growth
Allelopathic effects
Allelopathic “Symptoms” on plants planted near or under walnut. Yellowing, wilting and death of part or all of the plant Plants Damaged by juglone tree and fruits apple, grape, azalea, pine, rhododendron Vegetable & Herbs Thyme Tomato Potato
reducing allelopathic effects
Clean, destroy or fully compost walnut debris to degrade toxins.
Do not use any part of the walnut as compost or mulch for other plants
Maintain high Organic Matter(metabolise toxins)
Plant tolerant plants:Black cherry, raspberries, crabapple, papaya, pear (callery), sunflower, rose, geranium.
yield of walnut can be obtained in two ways
Seedling of the plant
Yield after 10-12 years
Fully commercial in 18-20 years after planting
2 Grafted plant
Yielding from the grafted part begins much earlier to the seedling plantation that is within 4-5 years of plantation
It become commercially productive in 8- 10 years after planting
Yield
Walnut tree produces 100-150 kg nuts but in average it yield up to 40 kg per walnut tree
Common pest and diseases
Walnut blight( Xanthomonas campestris pv.juglandis) Spray copper oxychloride
Deep Bark canker: Brennaria (=Erwinia) rubrifaciens
Avoid deep wounding during grafting
Red-Spotted Longhorn Beetle: (Batocera rufomaculata)
Presence of infected “ring bark’’
Control measures:
Remove and burn heavily-infected trees and branches
Destroy dead trees: serves as breeding place
Orchard sanitation
Harvesting
August-October
Maturity determination
Mature when nuts dehisce and fall
In higher altitude=kernel matures earlier to hull dehiscence
In lower altitude=hull dehiscence occur s prior to kernel maturity
Kernel matures when packing tissue around its halves turned brown
Harvesting method
Manually
Grade according to size, colour and variety
Store in gunny bags in the ventilated room
