Influence of foliar application of micronutrients on the ...

Journal of Hill Agriculture

I (I ):63-66 January-June

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2010

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Influence of foliar application of micronutrients on the fruit quality of guava cv. Lucknow-49 V RAWAT' YK TOMAR. JMS RAWAT

Received: May 19,2010; Revised: July 01, 2010; Accepted: July 10,2010

ABSTRACT The experiment was carried out during the rainy season of two successive years i.e., 2005 and 2006 on guava cv. Lucknow-49 (Sardar Guava) to improve the quality of fruits by foliar application of micronutrients i.e. zinc, copper and boron at 0.2, 0.3 and 0.4% alone and in combination of two and three, with control. TSS, total sugars, sugar-acid ratio and seed weight significantly improved whereas significant reduction in acidity was exhibited with the foliar application of zinc sulphate at 0.4 % concentration. Application of boron at 0.4 % concentration significantly increased the vitamin C and pectin content ofthe L-49 guava fTuits.Thus micronutrient spray with 0.4% zinc sulphate and 0.4% boric acid are beneficial for improvement of fruit quality in guava. KEYWORDS Guava, Lucknow-49, micronutrients, zinc, copper; boron Guava (Psidium guajava L.) is not only a delicious table fruit due to its excellent flavour, nutritive value and pectin content, but is also important fruit for processing industry for preparing many kinds of excellent products like jelly, jam, canned fruit products, fruit butter, toffee, cheese and guava nectar. It is a rich and cheap source of vitamin C and pectin (Agnihotri et al. 1962). Foliar feeding of nutrients to fruit plants has gained much importance in recent years which is quite economical

Rawat V

. Tomar

YK

. Rawat

JMS*

Department of Horticulture, HNB Garhwal University, Srinagar (Garhwal), Uttarakhand- 246 174,

and obviously an ideal way of evading the problems of nutrients availability and supplementing the fertilizers to the soil. Nutrients like nitrogen, phosphorus and potash playa vital role in promoting the plant vigour and productivity, whereas micronutrients like zinc, boron, copper and molybdenum perform a specific role in the growth and development of plant, quality produce and uptake of major nutrients. Keeping in view the importance of application of micronutrients for improving fruit quality, present study was c.onducted to evaluate the effect of micronutrients by foliar application, on fruit quality characteristics of L-49 guava in rainy season crop (Ambe Bahar). The study was conducted at Horticultural Research Centre and Department of Horticulture, HNB Garhwal University, Srinagar(Garhwal), Uttarakhand, India.Twelve year old sixty six bearing guava trees (cv. L-49) of uniform vigour, size and maintained under uniform cultural schedule were selected for the present studies. The experiment consisted of 22 treatment combinations of3 micronutrients viz., zinc, copper and boron at 0.2%, 0.3% and 0.4% and in combination of two and three except spray of plain tap water as control. Aqueous solutions of zinc, copper, boron and tap water were sprayed at the time of full bloom on rainy season crop (Ambe Bahar). The experiment was laid out in Randomized Block Design (RBD) with 3 replications of all the treatments. Micronutrient sprays were done at full bloom stage in early morning with the help of foot sprayer @ six liters per tree to ensure the maximum absorption of nutrients through the leaves. The weight of pulp and seeds was measured by using electronic top pan balance (Model Z

-400). Totalsoluble

solids (TSS) was measured by hand refractometer and values were corrected at 20°e. Acidity was determined by titrating the fruit pulp against 0.5 N NaOH and expressed

64

as % malic acid. Ascorbic acid was analyzed according to the method detailed by Ranganna(2004) and expressed as vitamin C mg/ 100 g. Similarly, soluble sugars were determined by the method ofMc Cready et a1.(1950). Foliar feeding of micro nutrients showed significant impact on TSS, acidity, total sugars and sugar acid ratio content of fruits. The highest total soluble solids (11. 78° Brix) were noted in the 0.4% zinc sulphate treatment, which gave the 19.45% increase over control (Table 1). It is an established fact that zinc is credited with definite role in the hydrolysis of complex polysaccharides into simple sugars, synthesis of metabolites and rapid translocation of photosynthetic products and minerals from other parts of the plants to developing fruits. Kumar and Bhusan (1980) reported that

foliar applicationof ZnSO4 increasedthe TSS contents by increasing photosynthetic activity of the plants resulting into the production of more sugars. All the treatments showed a general decline of fruit acidity with the concentration of increased micronutrients. The lowest acid offruit 0.4% was recorded with the spray of 0.4% zinc sulphate. The maximum reduction in acid content (27.89%) was also obtained under 0.4% zinc sulphate treatment. Lal and Sen (2001)

Journal of Hill Agriculture (Volume I, No. I January-June 2010)

reported that the foliar application of zinc sulphate reduced the acid content in guava fruits. Being a major substrate of respiration, the decline in the malic acid during fruit ripening might be the results of an increase in membrane permeability which allows acids to be stored in the respiring cells (K]iewer 1971). The downwards trend in the levels of organic acids was also possibly due to dilution effect with the increase in volume of fruits in these treatments. Foliar application of zinc sulphate alone at the higher concentration enhances the total sugar contents of the fruits in comparison to other nutrients and their combinations. The present findings show that the 0.4% concentration of zinc sulphate treatment gave the significantly higher total sugars (6.36%) in guava fruits as compared to all other treatments. The increase in total sugars under this treatment was to the tune ofthe 29.82% over the control. It is in agreement with the findings of Singh and Brahmachari (] 999) and Kundu and Mitra (1999) in guava. The perceptible increase in sugar contents through the foliar feeding of zinc sulphate might be due to the active synthesis of triptophan in the presence of zinc, the precursor of auxin, which in turn causes an increase in the rate of chlorophyll synthesis which

Table 1 Effect of foliar application of micronutrients on qualitative characters of guava cv. L-49 Treatments Seed TSS (OBrix) Acidity Total Sugar/acid Vitamin C Pulp (%) sugars (%) ratio (mg/IOOg) weight (g) weight (g) 10.75 0.431 5.60 13.00 148.54 106.18 2.03 Zn (0.2%) 11.31 0.419 5.88 14.05 153.45 108.23 2.03 Zn (0.3%) lU8 0.400 6.36 15.91 156.60 112.86 2.02 Zn (0.4%) 10.45 0.449 5.30 11.81 156.06 103.02 2.10 Cu (0.2%) r 10.68 0.445 5.59 12.56 162.60 104.02 2.09 Cu (0.3%) 10.87 0.443 5.75 12.98 166.07 111.12 2.11 Cu (0.4%) 10.72 0.434 5.56 12.81 165.42 108.14 2.06 B (0.2%) 11.04 0.431 5.67 13.14 168.81 110.97 B (0.3%) 2.03 11.42 0.420 5.88 13.99 173.56 114.90 2.03 B (0.4%) 0.482 5.25 10.91 148.23 10.41 104.41 2.10 Zn+Cu (0.2%) 10.60 0.463 5.36 lU8 151.26 105.60 2.09 Zn+Cu (0.3%) 10.68 0.460 5.66 12.31 154.23 111.05 2.05 Zn+Cu (0.4%) 10.73 0.457 5.45 11.99 153.32 109.74 2.06 Zn+B (0.2%) 10.81 0.452 5.64 12.46 157.43 112.43 2.05 Zn+B (0.3%) 11.38 0.445 5.85 13.13 161.64 115.39 2.05 Zn+B (0.4%) 10.35 0.510 5.13 10.07 160.94 105.53 2.10 Cu+B (0.2%) 10.50 0.489 5.24 10.69 167.03 106.74 2.10 Cu+B (0.3%) 10.59 0.464 5.46 11.76 170.61 112.22 2.11 Cu+B (0.4%) 0.442 5.34 12.09 163.16 114.25 2.11 Zn+Cu+B (0.2%) 10.51 0.438 5.61 12.81 168.13 116.93 2.11 Zn+Cu+B (0.3%) 10.71 0.434 5.78 13.33 170.36 119.78 2.10 Zn+Cu+B (0.4%) 11.31 Control 9.85 0.554 4.89 8.83 143.27 91.62 2.06 SEm.r 0.021 0.003 0.033 0.143 0.480 0.619 0.025 CD at 5% 0.039 0.005 0.059 0.260 0.874 1.126 0.045

Pulp/seed ratio 52.38 53.35 55.94 49.11 49.72 52.78 52.48 54.60 54.60 49.64 50.44 54.07 53.40 54.91 56.29 50.14 50.87 53.18 54.13 55.52 57.08 44.58 0.888 1.617

Pectin (%) 1.037 1.163 1.218 0.828 0.848 0.952 1.243 1.426 1.650 0.813 0.833 0.922 1.025 1.134 1.160 0.951 0.979 1.021 0.990 1.061 1.113 0.625 0.007 0.012

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Journal of Hill Agriculture (Volume I, No. I January-June 20 I0)

ultimately

accelerates

(Skoog1940).

the. photosynthetic

activity

.

The effects of micronutrients when sprayed singly or in combination were found promising. In the present findings, the trees treated with 0.4% concentration of zinc sulphate treatment resulted into the maximum sugar/acid ratio (15.90). There was 80.44% increase in sugar/acid ratio over the controL The present findings are also supported from the work of LaI and Sen (2001) and Kundu and Mitra (1999) in guava. Sprays of micronutrients either singly or in combination significantly influence the pectin content of L-49 guava fruits. It was observed that the pectin content increased with the increase in the concentration of micronutrients sprays from 0.2% to 0.4%. Boric acid treatment at 0.4% concentration was proved superior (1.650%) in pectin content with an increase of 163.96% over control. Pandey et al. (1988) also reported an improvement in pectin content of guava fruits by foliar application of boron. Boron has been found to be associated with plant system in various ways and increased the production of cellulose and pectin in the fruits, might be the possible reason of increased pectin contents in the fruits (Lee and Kim 1991). Boron increased the pectin contents in the fruits as it facilitates the process of translocation of photosynthates from leaves to the young fruits, which are partly used for the synthesis of pectic substances (Whiting 1970). Vitamin C content of the fruits was increased with the increased in the concentration of micronutrient application in all the treatments. An appreciable increase in vitamin C content was recorded in the fruits of boric acidm:ated trees. The maximum contentof vitamin C (173.5 mg per 100 g) was noted under 0.4% concentration of boric acid treatment with 21.22% increase over control. Singh and Brahmachari (1999) in guava and Singh et al. (2001) in aonla also found an increase in vitamin C content of fruits with boron spray. The higher ascorbic acid (vitamin C) levels during early stages of fruit growth may be attributed to adequate supply of hexose sugars via photosynthetic activity (Sharma 1984). The maximum pulp weight (119.78 g) in L-49 guava fruits was obtained with the spray of 0.4% concentration of zinc sulphate + copper sulphate + boric acid with an increase 000.76% overcontrol. Brahmachari and Kumar (1997) also reported increase in pulp weight of fruits with the foliar application of micronutrients in litchi and ber, respectively. The increase may be due to enhanced synthesis of metabolites, increased absorption of water and mobilization of sugars and minerals in the expended cells and intercellular spaces of the mesocarp. Boron either singly or in combination also helped in maximum increase in pulp by accelerating the transportation of

photosynthates from leaf to the developing fruits (Dugger 1983). The present studies have shown that the lowest seed weights (2.02 g to 2.03 g) were recorded under all the zinc sulphate concentrations and 0.3 and 0.4% boric acid treatments. Though, the foliar application of micronutrients gave a slight seed weight differences in favour ofthe zinc and boron treated trees. The reduction in seed content by zinc and boron treatments shows parthenocarpic effects to some extent. The highest pulp/seed ratio (57.08) was noticed under 0.4% zinc sulphate + copper sulphate + boric acid spray with an increase of 28.04% over control. The results of the present study are in line with the findings of Brahmachari and Kumar (1997) in guava fruits. The findings of this investigation are indicative of beneficial effects of single foliar application of micronutrients at full bloom stage on physico-chemical properties of guava fruits cv. L-49. The over all qualitative assessment of fruits, it can be concluded that the spray of zinc sulphate at 0.4% enhances the TSS, total sugars, sugar/acid ratio and reduced the acidity of the fruits, whereas boric acid spray at 0.4% increase the pectin and vitamin C contents of the fruits. REFERENCES Agnihotri BN, Kapoor KL, God KR 1962. Guava. In: A Textbook on Pomology, Chattopadhyay TK (ed), Vol II, Kalyani Pub, New Delhi, 277p Brahmachari VS, Kumar R 1997. Effect of foliar sprays of mineral nutrients on fruit set, retention and cracking of litchi (Litchi chinensis Sonn.) fruits. Haryana J Hort Sci 26 (3,4): 177-80. Dugger WM 1983. Boron. In: plant metabolism. Encyclopedia of Plant Physiology, Vol 15 B. Springer-verlag, Berlin, New York.

Kliewer WM 1971. The effect of day temperature and light intensity on concentration of malic and tartaric acids in Vitis vinifera. J Amer Soc Hort Sci 97: 372. Kumar S, Bhusan S 1980. Effect of zinc, manganese and boron applications on quality of Thompson Seedless grapes. Punjab Hort J 20: 62-65. Kundu S. Mitra SK 1999. Response of guava to foliar spray of copper, boron and zinc. Indian Agriculturist 43 (1,2): 4954. Lal G, Sen NL 2001. Effect ofN, Zn and Mn fertilization on fruit quality of guava (Psidium guajava L) cv. Allahabad Safeda. Haryana J Hort Sci 30 (3,4): 209-10. Lee SS, Kim KR 1991. Studies on the internal browning of apple fruits caused excessive boron application. J Korean Soc Hort Sci 32 (1): 43-51. Mc Cready RM, Guggot J, Silvaiera V, Owen HS 1950. Determination of starch and amylase in vegetables. Annals Chern 22: 1156-58.

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Pandey DK, Pathak RA, Pathak, RK 1988. Studies in foliar application of nutrients and plant growth regulators in Sardar guava (P.I'idium guajava L) I, effect on yield and fruit quality. Indian J Hort 45 (3-4): 197-02.

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