Tomato (Lycopersicon esculentum L.) belongs to Solanaceae family and is an important vegetable crop of Pakistan. It is originated in the America where its indigenous name was tomati. From Mexico tomato was taken to Europe and then to Asia [1]. Tomato plant is classified as warm-season crop and it required about 25°C to 29°C for its growth [2]. The optimum range of daytime temperatures for the growth and development of tomato plants has been reported to be between 25-30°C, with an upper limit of 35°C for growth, yield and fruit quality of tomatoes. Temperature above freezing may cause damage to both plant and fruit [3]. Hundred grams of edible parts of edible parts of tomato contains 0.9 g protein, 0.1 g fat, 3.5 g carbohydrates, 15-20 Kcal energy, 500-1000 IU vitamin “A”, 0.1 mg thiamine, 0.02 mg riboflavin, 0.6 mg niacin, 20-30 mg vitamin “C”, 6-9 mg calcium, 0.8 g fiber and 0.3 mg iron. Tomato also has high medicinal values; vitamins are important bone growth, cell division and differentiation, maintaining surface lining of eyes, respiratory and intestinal tracts. Vitamin C is important in forming collagen, a protein that gives structure to bones, cartilage, muscles and blood vessels. It also helps in absorption of iron [4]. Boron is an essential and important micronutrient for the vegetative and reproductive growth of the tomato. Boron deficiency symptoms generally appear first on the younger leaves at the top of the plants; plants fail to produce functional flowers and may produce no seeds. Plants subjected to boron deficiency have been observed to result in sterility or low germination of pollen. Failure to set fruit is common, and the fruit may be ridged, show corky patches, and ripens unevenly [5]. Many physiological disorders have been studied in tomato and blossom-and rot is a main quality deteriorating physiological disorder that occurs worldwide wherever tomatoes are grown. This disorder resulted in direct fruit losses upto 50%. Most cultivars of tomato can be affected by this physiological disorder, although differences in susceptibility have been reported [6]. Blossomend rot in tomato is characterized by brown pectinaceous inclusions occurring in the epidermis and pericarp, at the stylar end of the fruit. Cell membranes become disorganized and tissue necrosis develops underneath, with the skin remaining intact. Calcium starvation is considered as a major contributing factor for blossom end-rot in tomato [7]. The nutrients applied through foliar method are instantly available to a plant that is why this method is better than others [8]. An important practice in tomato production is the use of starter fertilizer, a mild fertilizer solution in the water used around each plant at transplanting. Starter fertilizers have soluble phosphate and nitrogen in ratio of 3:1. The high phosphate with some nitrogen encourages earlier root growth and rapid plant establishment [9].

The experiment was conducted at University of Agriculture, Faisalabad, Pakistan during year 2011-2012. This field experiment was laid out in a Randomized Complete Block Design (RCBD) with twelve treatments+one absolute control which replicated thrice to investigate the effect of different concentrations and combinations of boron (boric acid), calcium (CaCl₂) and nitrogen (urea) as foliar application (3 sprays) at 10 days intervals on tomato. Crop was looked after properly. The following treatments were studied. (T0) control (T1), Boron 0.1% solution (T2), Boron 0.2% solution (T3), Calcium 0.2% solution (T4), Calcium 0.3% solution (T5), Nitrogen (Urea)=2% solution (T6), Nitrogen (Urea)=3% solution (T7), Boron (boric acid)=0.1%+calcium chloride=0.2% solution (T8), Boron (boric acid)=0.1%+calcium chloride=0.3% solution (T9), Boron (boric acid)=0.2%+calcium chloride=0.2% solution (T10), Boron (boric acid)=0.2%+calcium chloride=0.3% solution (T11), Boron (boric acid)=0.1%+calcium chloride=0.2%+nitrogen (urea)=2% solution (T12), Boron (boric acid)=0.2%+calcium chloride=0.3%+nitrogen (urea)=3% solution. Data related to different parameters like plant height, number of leaves per plant, number of flowers per plant, number of clusters per plant, number of flowers per cluster, number of fruits per plant, average fruit weight (g), yield per plant (kg), number of infected fruits per plant, total soluble solids%, fruit color, lycopene content will be collected and analyzed using STATISTICA computer program. The least significant difference at 5% level of probability was used to test the differences among mean values [10].

Vegetative growth characters

Data presented in Table 1 indicated that the vegetative growth characters of tomato, i.e., plant height and number of leaves were significantly affected by the tested treatments. Clear also, that treatment T12 applying boron (0.2%) with foliar spraying by calcium (0.3%) plus nitrogen fertilizer (3%) gave the best plant growth parameters, then other treatments and T0 (Control) was the lowest. These results might be due to availability and rapid uptake of nitrogen since it is a primary component of all nucleic acids, protein and chlorophyll.

Table 1: Foliar application effect of boron, calcium and nitrogen on plant height and number of leaves per plant. Means followed by the same letter in a column do not differ significantly at p ≤ 0.05%.

On the other hand, boron plays an important role in activation of cell division and cell elongation. As well as calcium is important for proper cell division, cell elongation, cell wall development, Nitrate uptake and metabolism. Therefore, boron, calcium and nitrogen enhance the number of metabolites necessary for building plant organs, consequently the vegetative growth of plants [11]. The obtained results are in general agreement with those reported [12-16].

Flowering traits

The effect of foliar sprays of boron, calcium, nitrogen on number of flowers/plant, number of flower clusters/plant, number of flowers/ cluster were significant in this experiment presented in Table 2 in all treatments of the experiment T12 boron (0.2%) with foliar spraying by calcium (0.3%) plus nitrogen fertilizer (3%) reflected more number of flowers per plant, number of flower cluster per plant and number of flowers per cluster than other treatments. The obtained results seemed to be in general agreements with those reported by foliar application of boric acid significantly influence the flowering [17]. Application of nitrogen gave the best results in number of flower [18-22].

Table 2: Foliar application effect of boron, calcium and nitrogen on number of flowers per plant, number of flower cluster per plant and number of flowers per cluster. Means followed by the same letter in a column do not differ significantly at p ≤ 0.05%.

Yield and its components

The data in Table 3 show that number of fruits per plant, fruit weight and yield per plant were significantly affected by different treatments, whereas, the maximum value of number of fruits, fruit weight and yield per plant was recorded in T12 (Boron (boric acid)=0.2%+calcium chloride=0.3%+nitrogen (urea)=3%). It may also be stated that the sufficient application and the efficient absorption of N and foliar calcium and boron addition were promote the production of more photosynthesis required for good fruit tomato yield and its components. These results agree with those reported [23-26].

Table 3: Foliar application effect of boron, calcium and nitrogen on number of fruits per plant, fruit weight and yield per plant. Means followed by the same letter in a column do not differ significantly at p ≤ 0.05%.

In this experiment foliar application of boron, calcium and nitrogen were applied on tomato. Among all treatments in experiment T12 (Boron (boric acid)=0.2%+calcium chloride=0.3%+nitrogen (urea)=3% solution) proved better results in all parameters (vegetative growth characters, flowering traits, and yield components) followed by T10 which shows nearly same effect then other treatments (Boron (boric acid)=0.2%+calcium chloride=0.3% solution) while T0 (control) was found at the bottom among all treatments. Based on this experiment treatment T12 is recommended as best nutrients combination and concentration that can be used for the farmer practices to get better production.