Origin and distribution
Hazelnut is known as a cob nut or filbert nut, belongs to the family Corylaceae. It is distributed in the temperate zone extending from Japan, China, Turkey, India, and Europe to North America. However, species in different regions are different. In India, the species of hazelnut are C. jacquemontii Dne. And C. ferox commonly referred to as Himalayan hazelnut.
Vernacularly, it is called Winri, Wiri, Warrawi, Wuriya in Kashmir; Thangi, Thangoliin in Pangi in HP; Bhutia badam in Garhwal Uttarakhand and Kapasi in Kumaon in Uttarakhand. It is grown naturally in Pangi, Khadapatther, Sungri, Khadrala and Larot in Chansel peak of HP and upper areas of Garhwal and Kumaon regions. The major hazelnut producing countries are Turkey, Italy, USA and China.
The plants are about 2-4 m tall, strongly rhizomatous, main stem straight, with spreading ascending branches, twig with numerous stiff, red granular hairs. Leaves are deciduous, alternate, broad oval with a heart shape or round base, doubly serrate, having beneath and petiolate. It is monoecious, the male flowers numerous with pendulous stalks (catkins), 3-8 cm long in clusters while female flowers are several in tiny scaly buds, which are almost entirely enclosed by bracts near the end of twigs. It reaches to bearing after 3-4 years of planting. Fruits are light brown colour, acone like nut 1-2 cm wider enclosed in two husks like bracts.
Nutritional value and uses
Hazelnut is extensively used in confectionery to make praline and also used in combination of chocolate for chocolate truffles. Hazelnut oil is strongly flavoured and rich in unsaturated fatty acids, used in cooking oil in the USA. Recently University of Genova, Italy has confirmed the presence of taxanes in the shells and leaves of hazelnut plants, which is used in cancer treatment. Nutritional value of dried fruits of hazelnut has a significant place for human health and a good source of energy with more than 60% fat content. Hazelnuts are rich in protein and unsaturated fats. Moreover, they contain significant amounts of vitamin B1, B3 and vitamin B6.
Hazelnut grows in deep, fertile and well-drained soils. The soil should be well aerated and have good depth. Hazelnut requires cool climate and long cool summer Corylus jacquemontii Hazel nut fruits is said more favourable for the development of the nuts than longer warm summer. Plants can be propagated by air-layering, grafting and budding. C.colurna is recommended rootstock for cultivated hazelnut (C. avellana). However, propagation through rooted suckers is also found successful. Planting is done at a distance of 4×4 m in the pits of 1 x 1 x 1 m.
The trees may be trained to what is known as the core form in which about six branches are trained diagonally outward. The centre is kept open by cutting outgrowth, and water sprouts are also pulled out. Pruning should be done in December- January when trees are dormant. In autumn, doses of FYM @ of 20-25 kg and 500 g NPK in the ratio of 1:2:1 may be applied /tree per year to harvest a good crop. Hazel nut plants require limited water, and they are rarely irrigated if planted on fertile soils with good water holding capacity.
On bearing tree, the lateral branches on main branches should be pruned each year for good plant canopy. The removal of suckers from the base is the common practice in hazelnut cultivation. However, the suckers can be reduced by root pruning at the time of planting. The male catkins emerge during June month. Pistillate flowers are borne in tight clusters. Nuts are usually borne in lateral and terminal buds on the previous season’s growth. Self-incompatibility in hazelnut cultivars is common, which makes inter-planting necessary to provide cross-pollination.
The blooming in hazelnut is dichogamous and therefore, the appearance of staminate and pistillate flowers may not be synchronized. Thus need pollinizer cultivars sharing 10% of the total population, Proper fertilization of flowers is necessary for the developments of nuts otherwise nuts are empty without kernels. Fruits mature in the month of September-October and sometimes fall on the ground upon maturity. Unshelled nuts can be stored for a year and shelled kernel for 4-5 months in winter.
A total of 20 accessions of hazelnut (15 exotic of C. avellana and five indigenous of C jacquemontii) are being maintained in the field gene bank. The exotic accessions have been introduced from USA and Italy while indigenous accessions procured from Himachal Pradesh and West Bengal.
- National Bureau of Plant Genetic Resources Regional Station Phagli, Shimla