Plantation Crops

Propagation in cashew

Seedling propagation
Though it is commonly practiced method of cashew propagation, it is not encouraged due to high proportion of cross pollination leading to considerable variability among seedling progenies.

Clonal / Vegetative propagation
Cashew is amenable for vegetative propagation by different methods.
¤ Grafting 
¤ Epicotyl
¤ Soft wood
¤ Veneer
¤ Side grafting 
¤ Top working etc 
¤ Budding and
¤ Layering i.e., air layering and Mound layering/ Stool layering (Stooling) etc.

Soft wood grafting
Among the vegetative propagation methods soft wood grafting is more successful in most of the cashew growing areas. It is similar to epicotyl method of grafting but differ only with respect to age of the seedlings (root stocks) used for multiplication. In soft wood grafting 30 -40 days old seedlings with 1 to 2 pairs of leaves are retained on root stocks while grafting. However, usually soft portion of the seedlings at 15 -20 cm from ground level is availed for grafting.
For grafting 10-12 cm long pencil thick scion from current seasons growth should be selected and precured. Precuring is done by clipping off the lamina leaving the petiole intact on the shoots. Within few days these petiols drop-off indicating the shoots are getting cured. Due to storage of food material the shoots get thickened and the terminal bud appears swollen. This swollen condition indicates that shoots are ready for separation from the tree. Precuring is done to increase the meristamatic activity in the auxiliary and terminal buds.
Wedge technique is used for grafting. Two pairs of bottom leaves are retained on the stock and the stock is decapitated 5cm above the second pair of leaves and a vertical incision, along the length of the stump to 3.75cm from the top of the stock is made. The scion is prepared like a wedge. It is inserted into the stock and tied with polythene strip of 1.5cm width and 30cm length of 100 gauge. To create a humid atmosphere around the scion bud, polythene caps of 20 x 2.5cm size of 100 guage thickness is provided for 15-20 days till the buds sprout.
The grafts are kept under shade or in a mist chamber preferably since humidity and temperature can be controlled. Application of NPK @ 150:20:100 ppm supplied through irrigation water helps in better survival of grafts. When the buds are sprouted remove polythene caps and grafts are shifted to open place. The successful graft shows signs of growth within 3-4 weeks after grafting. The success percentage in soft wood grafting is more during March- September under Kerala conditions. .

Planting and management of grafts in the main field
The softwood grafts are planted in pits of 50 cm3 with topsoil and 5-10 kg of compost or dried cow dung per pit after removing the polythene bags during June- July. Care should be taken while planting to see that the graft union is 2.5cm above the ground level. The polythene tape is to be carefully cut and removed. Staking should be done immediately after planting to protect the grafts from damage.