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
