Temprate Fruits (1+1)

PROPAGATION AND CANOPY MANAGEMENT

Rootstock and Propagation:-

• Walnut seedlings of Juglans regia are generally used as a rootstock for walnut in all over the world, however, in USA seeds of J. hindsi, Paradox (J. hindsii x J. regia) are used for raising seedling rootstocks.
• Traditionally, walnut in India is propagated by seed. Although sexual method is the most efficient and economical but not satisfactory, because the seedlings are highly variable, having long juvenile period, producing the nuts with inferior quality and with low shelling percentage.
• In India,r Persian walnut known as akhrot is most common source of seed.
• The seeds are stratified for 90-110 days at low temperature 4-5o C to break the seed dormancy.
• Various pre-sowing treatments with growth regulators, scarification and water soaking etc. not only reduce the stratification requirement and improve seed germination but also enhance seedling growth.
• Soaking of seed in 750- 1000ppm GA3 or 1000 ppm etherel solution for 24 hours after stratification is very effective in stimulating seed germination.
• The stratified seeds are sown in line 30cm apart at a distance of 15-20 cm and at a depth of 10-15 cm in Feburary – March.
• The nursery beds are covered with mulching and regular irrigation and weeding is done so that seedling become graftable or buddable in one year.

Propagation

• The seedlings are grafted with tongue method during February in mid hill and in March in high hill conditions.
• Side veneer grafting gives best results when performed during July- August.
• Walnut is very difficult to propagate and gives low success with grafting.
• Budding with Chip method in mid May to first week of June, and annular budding and patch budding performed in end June to mid July gave 80-85% bud-take success.

Planting:-

• Planting distance and density varies with the soil, rootstock, topography and nature of bearing habit of varieties.
• On flat land, square or rectangular system and on sloppy land contour and terrace systems of layout are adopted.
• The planting is done any time from December to March but establishment of plants are better in early planting.
• In general, the planting is done at a spacing of 10-12 meter in grafted plants and for seedling plants the spacing of 15 x 15 meter is recommended.
• However, lateral bearing varieties raised on clonal rootstocks like paradox are planted at a spacing of 8 x 8 meter.

Training and Pruning:-

• Walnut trees are mainly trained according to modified leader system.
• After planting, the plants are headed back to 60-70 cm above graft union.
• The most vigorous upright limbs is selected after one year growth, removing the other shoots but leaving one or two small lower limbs on South West side to protect the tree from sun burn.
• The first main frame work branch should be 4-5 feet from the ground. The frame work of the tree is made in such a way that branches are spaced far, both vertically and horizontally.
• Care should be taken that in the cultivar which fruits laterally, a large number of new shoots are headed back on the periphery to reduce fruit and increase vigorous shoot growth throughout the tree periphery.
• In contrast, on the terminal bearing cultivars, pruning consists of heading back of selected framework branches and thinning out of competing limbs.
• Shading become a problem in a mature tree, hence thinning out of limbs in the top and sides of the tree should be done.
• The best method of pruning of tree of age below 16-35 years old is to cut back to 4-5 years old shoots.