Introduction
Almond (Prunus dulcis Batsch) belongs to family Rosaceae is one of the important nut crops of temperate region of India, mainly grown in Kashmir valley. In India it is grown over an area of 23,200 hectares with an annual production of 16,300  tonnes and productivity 0.7 t/ha as compared to other almond producing countries such as UAE (33.3 t/ha),Jordan (7.73 t/ha), Lebanon (5.82 t/ha) , Afghanistan (4.99 t/ha), USA (4.85 t/ha), Turkey (3.23 t/ha), Kazakhstan (3.12 t/ha), China (3.08 t/ha), Israel (3.0 t/ha) and Chile (2.89 t/ha), respectively (FAO, 2010). Almond kernels are concentrated sources of energy with a significant share of fat, protein and fibre. Fats are primarily non saturated, mostly oleinic and linoleic fatty acids. Non saturated fatty acid is an important in maintaining low cholesterol levels in the blood and significant amount of micro-nutrients (Aslanta et al., 2001). The kernel contains between 5.93-7.27 % water, 8.03-8.13 % ash, 53.67-54.26 % oil, 23.03-23.98 % protein, 4.15-5.29% total sugars, 1546-1685 mg/100 g K, 253-259 mg/100 g P, 640-678 mg/100 g Ca, 447-494 mg/100 g Mg, 24.30-25.80 ppm Cu, 76.33-80.50 ppm Zn, 54.83-65.33 ppm Fe and 37.67-37.83 ppm Mn (Aslanta et al., 2001). Kernel taste inheritance in almond reported by Vargas (Vargas et al., 2001).Commercial almond production in India is low considering the demand and economical potential. However, domestic demands is increasing every year, with the result, the country is importing almond to the tune of more than Rs.1500 crores annually. The almond cultivars play an important role in improving the production and productivity under Kashmir condition. The improved indigenous almond cultuvars such as Makhdoom, Shalimar and Waris and exotic cultivars such as Non Pareil, IXL, Pranyaj, Primorskij, Merced and California Paper shell are performing well under Kashmir condition. Evaluation of almond variety in Karaj (Damvar and Hassani, 2006) for yield and quality traits. Regional almond variety evaluation in California (Lapinen et al., 2002).The plant growth habit and fruiting behaviour vary in different cultivars of almond. Keeping this in view, an attempt was made to evaluate the performance of different almond cultivars under North West Himalayan region of India.
 
Materials and Methods
Experimental layout
The experiment was conducted at ICAR-Central Institute of Temperate Horticulture, Old Air Field, Rangreth, Srinagar, Jammu & Kashmir during 2008-09 to 2012-13 to study the performance of almond cultivars under North West Himalaya region of India. The Research farm at Srinagar is situated at a latitude of 34° 05'N and longitude of 74° 50'E and at an altitude of 1640 m above msl. The soils of this experimental field are silty loam (39.60 % sand, 24.0 % Silt and 36.40 % clay; 7.5 soil pH, 0.50 % soil organic carbon, 462 kg N/ha, 9.59 kg P/ha and 279 kg K/ha) with poor drainage. The treatment comprised of nine almond cultivars such as Makhdoom, Waris, Shalimar, Non Pareil, IXL, Pranyaj, Primorkij, Merced and California Paper shell have been laid out in randomised block design with three replications and two plants/replications/treatments as plant unit. These cultivars planted at 4 x 4 m spacing in an experimental field during 2002-03.
 
Climatic conditions
The experimental farm falls under temperate region having cold conditions from November to February and four year mean maximum and minimum temperature of Srinagar climate indicated that maximum 30 °C in August and minimum -2.1 °C in December month (Figure 1). The mean annual precipitation is 620 mm distributed erratically throughout the year (Figure 2).

Measurements and observations
The plants were given uniform cultural treatment and irrigated through drip irrigation on daily basis during summer. Canopy volume (CV) was estimated for each individual tree using a geometrical model referred to as the “contour method” (CV = [(1⁄4) π a b h) / (m(x) + m(y) + 1]. The dimensions a and b were measured of the width of the tree at the base of the canopy, perpendicular and parallel to the tree row orientation, respectively. The height of the canopy (h) was measured from the lowest branch to the apex. The functions m (x) and m(y) were derived to accommodate the contour of the tree (Wright et al., 2005). Canopy volume measurements were made after harvest in October 2009 to 2012. Tree trunk girth was recorded before the execution and at the end of experiment during both the years of study. A ring was made with red paint at a height of 15 cm above the ground level in each selected tree to record the trunk girth from same point each year. The trunk cross-sectional area (TCSA) of tree was calculated by using formula TCSA= Girth 2/4 л. Fruit was harvested at maturity, hulled, dried and nut weight in gram and yield per tree was recorded in kilogram. Nut and kernel size was determined by observing the length and diameter was measured by Vernier caliper and thickness of shell was measured by Screw gauge and both were expressed in millimetre. The data over four years of experimentations were analyzed statistically as per Steel and Torrie (1986) for interpretation of results and drawing conclusions.
 
Results and Discussion
Plant growth
The Trunk cross sectional area (TCSA) of tree ranged from 95 to 152.02 with standard deviation (21.02) and coefficient of variations (16.88) in different cultivars of almond (Table 2). The TCSA increases with increasing the age of the tree in almond (Figure 3). Significantly maximum TCSA (111.47 cm² and 141.22 cm²) were recorded in Non Pareil cultivar of almond closely followed by Pranyaj (111.12 cm² and 135.22 cm²) in 2009-10 and 2010-11. Whereas, 2011-12 and 2012-13, Waris cultivar registered highest TCSA (181.85 cm² and 186.45 cm²) in almond. The canopy volume of tree is one of the important parameters to differentiate the almond cultivar. It ranged (8.55-11.53) with mean (9.92) and coefficient of variation (10.10) in almond. The canopy volume also increases with increasing the age of the tree in different cultivar of almond (Figure 4). Maximum canopy volume was recorded in Non Pareil cultivar (6.75 m³, 8.70m³, 12.76 m³ and 17.90 m³) followed by Waris (6.45 m³, 8.32 m³, 12.25 m³ and 17.02 m³) in 2009-10, 2010-11, 2011-12 and 2012-13, respectively.  There is positive and linear relationship between TCSA and canopy volume of tree in almond. The higher TCSA and canopy volume in Non Pareil cultivar of almond might be due to vigorous nature of the tree growth habit. Similar observations were reported by Kumar (Kumar et al. 2012).
 

 Flowering
Data presented in table 1 indicated that earliest bud burst (14.03.2012), first flowering (16.03.2012), 75% flowering (19.03.2012), 100% flowering (22.03.2012) and fruit set (30.03.2012) were recorded in almond cultivar Makhdoon. Whereas, late bud burst (22.03.2012), first flowering (23.03.2012), 75% flowering (27.03.2012), 100% flowering (31.03.2015) and fruit set (04.04.2012) were recorded in California paper Shell cultivar of almond. An early flowering and fruit set in Makhdoom and late flowering and fruit set in California Paper Shell might be due to varietal characters of a particular cultivar.
 

Nut yield
Nut yield is one of the important characters for productivity enhancement in almond. The nut yield varied (9.81-19.66) with standard deviation (2.24) and coefficient of variation (19.45) in almond (Table 2).  Significantly maximum nut yield (4.25 kg/tree and 2.65 t/ha; 4.71 kg/tree and 2.94 t/ha; 2.62 kg/tree and 1.64 t/ha) were recorded in 2009-10, 2010-11 and 2011-12, respectively in Pranyaj cultivar of almond. Whereas, in 2012-13, Merced variety registered highest nut yield (8.15 kg/tree and 5.09 t/ha) in almond. The overall cumulative nut yield (12.28 t/ha) was recorded in Pranyaj followed by Merced (11.09 t/ha), Makhdoom (9.57 t/ha) and Non Pareil (9.41 t/ha), respectively (Table 3).The performance of all cultivars of almond were superior in respect to nut yield. The higher nut yield per tree or per hectare in Pranyaj and Merced variety might be due to inherent character having prolific and profuse bearing habit of this cultivar. Similar results were reported by Ahmed and Verma (2009).
 

Nut and kernel characters
Nut characters varied in different cultivars of almond. The nut weight, nut length, nut diameter and nut length and dia ratio ranged (1.69-3.90, 31.20-48.65, 18.38-23.40 and 1.46-2.39) with standard deviation (0.77, 5.31, 1.45 and 0.30) and coefficient of variations (31.69, 14.32, 7.01 and 16.95) in almond (Table 2). The kernel weight, size and ratio ranged (1.04-2.06, 21.34-29.74, 11.24-15.15 and 1.72-2.56) with standard deviation (0.37, 2.90, 1.36 and 0.28) and coefficient of variations (26.72, 10.96, 10.58 and 13.51) in almond. Significantly highest nut weight (3.90 g) and kernel weight (2.06 g) were recorded in IXL cultivar of almond. Whereas, maximum nut and kernel size (48.65 mm x 20.32 mm and 29.74 x 11.59 mm) and length/dia ratio of nut and kernel (2.39 and 2.56) were recorded in California Paper Shell (Table 4). The shell thickness and weight of nut is one of the important quality characters of almond. It ranged (1.38-2.88 and 0.55-2.02) with standard deviation (0.50 and 0.53) and highest coefficient of variations (25.24 and 50.38) in almond. Minimum shell thickness (1.38 mm) and shell weight (0.54 g) were recorded in Merced cultivar of almond. The highest nut and kernel weight in IXL variety might be due to inherent characters of cultivar.  Nut and Kernel size were highest in California Paper Shell might be due to varietal characters. Least shell thickness and weight in Merced variety of almond might be due to inherent character of the cultivar. Strikic et al. (2010) indicated that thin shell resulted better almond quality.Variability were found in nut characters of almond were reported by Colic et al.2012.

Conclusion
The results of the experiment showed that among the cultivars, late bud burst were noticed in Pranyaj (21.3.2012), Merced (21.3.2012) and California Paper Shell (22.3.2012), respectively. The cumulative nut yield (19.66 kg/tree and 12 28 t/ha) were highest in Pranyaj followed by Merced (17.76 kg/tree and 11.09 t/ha) and Makhdoom (15.33 kg/tree and 9.57 t/ha) in almond. Whereas, highest nut and kernel weight (3.90 g and 2.06 g) was recorded in IXL cultivar. By growing of these promising cultivars, the productivity may improve several times than existing one in the north west Himalayan region of India.

References
Ahmed N., and Verma M.K., 2009, Scientific almond cultivation for higher returns, Booklet-01/2009, CITR. Srinagar, Jammu and Kashmir, pp.14

Aslanta R., Guleryuz M., and Tarun M., 2001, Some chemical contents of selected almond (Prunus  amygdalus Batsch) types, In: AK BE (ed) 11 GREMPA Seminar on pistachios and almonds, Cahiers Options Mediterraneennes, 56:347-350

Colic S., and Zec G., 2007. Morphological and pomological traits variability of almond genotypes from Slankamen hill population, Genetika, 39:291-296
http://dx.doi.org/10.2298/GENSR0703291C

Colic S., Rakonjac V., Zec G., Nicoli D., and Fotiric Aksi M., 2012, Morphological and biochemical evaluation of selected almond (Prunus dulcis mill.) D.A. Webb genotypes in north Serbia, Turkish Journal of Agriculture Forestry, 36: 429-438

Damvar S., and Hassani D., 2006, Evaluation of almond cultivars in Karaj, Acta Horticulturae, 662: 151-156
http://dx.doi.org/10.17660/actahortic.2006.726.15 

F.A.O., 2010, Food and agricultural Organization of the United Nations, 11th December 2012<http://faostat.fao.org/site/567/default.aspx#ancor

Hill S. J., Stephenson D. W., and Taylor K., 1987, Almond yield in relation to tree size, Seientia Horticulturae, 33:97-111
http://dx.doi.org/10.1016/0304-4238(87)90036-7

Kumar D., Ahmed N., and Verma M.K., 2012, Studies on high density planting in almond in Kashmir valley, Indian Journal of Horticulture, 69(3): 328-332

Lampinen B.D., Gradziel T.M., Yeager J.T., Thorpe M.A., and Micke W.C, 2002, Regional almond variety trials for cultivar evaluation in California, Acta Horticulturae (ISHS) 591:457-464
http://dx.doi.org/10.17660/ActaHortic.2002.591.69

Steel R.G.T., and Torrie J.H., 1986, Principles and procedure of statistics, Me Graw Hill International Book Co., Singapore, pp. 348-354

Strikic F., Radunic M., Paskovic I., Klepo T., and Cmelik Z., 2010, Morphological and pomological traits of almond phenotypes (Amygdalus communis L.) isolated from their natural population, African Journal of Biotechnology, 9(4): 454-460

Vargas F.J., Romero M.A., Battle, I., 2001, Kernel taste inheritance in almond, In: AK B.E.(ed) 11 GREMPA, Seminar on pistachios and almonds, Cahiers Options Mediterraneennes,56:129-134

Wright H., Nichols D., Embree C., 2006, Evaluating the accountability of trunk size and canopy volume models for determining apple tree production potential across diverse management regimes, Acta Horticulturae, 707:237-243.
http://dx.doi.org/10.17660/ActaHortic.2006.707.30