RESPONSE OF OKRA TO ZINC AND BORON MICRONUTRIENTS

Transcription

1 Veg. Sci. 36(3 Suppl.) : (2009) RESPONSE OF OKRA TO ZINC AND BORON MICRONUTRIENTS SANJAY KUMAR, S.K. CHANKHAR AND M.K. RANA Chaudhary Charan Singh Haryana Agricultural University, Hisar Summary Results of the field experiment conducted at Research Farm, CCS Haryana Agricultural University, Hisar during rainy season of 2006 and 2007 revealed that the soil application of zinc sulphate and borax along with recommended dose of NPK as basal dose before sowing significantly influenced all the plant characters. Plant height, number of branches, fruit length, fruit diameter, average fruit weight and fruit yield were maximum with treatment combination of zinc sulphate 40 kg/ha and borax 15 kg/ha. Similarly, the protein content of okra [Abelmoschus esculentus (L.) Moench] fruits also increased with the increased level of zinc sulphate and borax being maximum with the highest level of zinc sulphate (40 kg/ha) and borax (15 kg/ha) applied in soil independently and in combination. Combination of zinc sulphate (30 kg/ha) and borax (15 kg/ha) increased the contents of chlorophyll a, chlorophyll b and total chlorophyll to their maximum. lkjka'k fhk.mh ij fd;s x;s iz{ks= ijh{k.k ls Kkr gqvk fd ftad lyqsv o cksjsdl ds lkfk u=tu QkLQksjl o iksvk'k dh lalrqr ek=k dk vk/kkjh; iz;ksx ls iks/ks ds lhkh xq.kksa esa lkfkzd izhkko ik;k x;ka iks/k Å pkbz] 'kk[kk la[;k] Qy yeckbz] Qy&O;kl] vkslr Qy Hkkj o Qy mit T;knk izkir gqvk tc ftax lyqsv dh 40 fdxzk-@gsdvs;j rfkk cksjsdl 15 fdxzk-@gsdvs;j fn;k x;ka blh izdkj fhk.mh esa izksvhu dh o`f)] ftad lyqsv o cksjsdl ds iz;ksx ds lkfk c<+rh x;ha lcls vf/kd Lrj ftad lyqsv dh 40-0 fdxzk-@gs- rfkk cksjsdl 15 fdxzk-@gs- vdsys ;k la;qdr :i ls eǹk esa nh x;ha la;qdr :i ls ftax lyqsv ¼30 fdxzk-@gs-½ rfkk cksjsdl ¼15 fdxzk-@gs-½ ds iz;ksx ls DyksjksfQy ^,*] DyksjksfQy ^ch* rfkk dqy DyksjksfQy esa vf/kd o`f) jgha Introduction Application of fertilizers is one of the most important agronomical practices to boost the crop productivity. The increase in growth and yield and improvement in quality of any crop is linked with physiological activities of the plants for which the micronutrients are equally important. They are required by plants in small quantity but are essential for higher crop yield and quality produce. Zinc plays an important role in fundamental processes involved in cellular mechanism and respiration, which ultimately affect the growth and development of crop plants. Similarly, boron exhibits pronounced effect on yield and yield attributing characters. With the increasing cropping intensity besides major nutrients, micronutrients have also become a limiting factor for obtaining the optimum yield. In Haryana, normally two crops of okra are taken, once in spring-summer and another in rainy season, however, the rainy season crop is more important and quite large acreage is covered under this crop. About 54 and 2.8% of the total area of Haryana is under the deficiency of zinc and boron respectively. Application of zinc and boron gives many favourable results in several vegetable crops and increases their yield significantly. However, the information on the effect of these micronutrients on okra production is scanty. Materials and methods A field experiment comprising twenty treatments combinations of zinc and boron was conducted at Vegetable Research Farm, CCS Haryana Agricultural University, Hisar in sandy loam soil under semi-arid conditions during rainy season of 2006 and Five levels of zinc sulphate (0, 10, 20, 30 and 40 kg/ha) and four borax (0, 5, 10 and 15 kg/ha) along with recommended dose of NPK (100:50:50 kg/ha) were applied in soil as basal dose before sowing. Zinc sulphate was used as source of zinc and borax as a source of boron. The crop was sown in plots of 2.8 x 2.5 m size at a spacing of 60 x 30 cm in a randomized block design with three replications. The observations on number of branches, fruit length, fruit diameter, average fruit weight and fruit yield were recorded on randomly selected five plants in each treatment. Green tender fruits (406 days old) were used for the estimation of quality parameters viz., protein, chlorophyll (a, b and total), zinc and boron contents. To estimate protein content, nitrogen content in fruits was

2 328 KUMAR ET AL. determined (Jackson, 1958). Chlorophyll content (a and b) was ascertained (Witham et al., 1971). Zinc and boron content were determined using Atomic Adsorption Spectrophotometer and Spectrophotometer with azomethine II reagent (Antil et al., 2002). The data were analyzed statistically and correlation between yield and growth parameters was worked out. Results and discussion Growth characteristics: The soil application of zinc and boron influenced the plant height significantly at all stages of crop growth (at 45 and 60 days after sowing and at final harvest) of branches per plant, too. At final harvest, the maximum plant height (99.19 cm and 95.2 cm) and number of branches per plant (2.83 and 2.78) was recorded with zinc sulphate 40 kg/ha and borax 15 kg/ha, respectively. The interaction of zinc sulphate and borax was significant for plant height only. The maximum plant height ( cm) was recorded with the application with of zinc sulphate 40 kg/ha along with borax 15 kg/ha. This increase in the plant height and number of branches might be due to the synthesis of tryptophan in the presence of zinc, the precursor of IAA, which stimulated the growth of the plant tissues (Naruka et al., 2000). Similarly, Kumar and Sen (2004) exhibited a pronounced effect of boron on plant to increase its vegetative growth since boron is found associated with the development of cell wall and with the process of cell differentiation, helping in the root and shoot growth of the plant. Non-significant interactive effect of boron and zinc with respect of branches per plant might be due to no involvement of micronutrients in activating lateral buds leading to primary branches (Hazra et al., 1987). Fruit characteristics: Soil application of zinc sulphate and borax alone has significantly positive effect on fruit length, fruit diameter and fruit weight (Table 2 and 3). The maximum fruit length (9.15 cm and 8.91 cm), fruit diameter (1.52 and 1.50 cm) and average fruit weight (10.07 and 9.74 g) were measured with the application of zinc sulphate 40 kg/ha and with borax 15 kg/ha, respectively. The minimum fruit length (7.46 cm), fruit diameter (1.34 cm) and average fruit weight (7.23 g) were recorded in control treatment. The interaction of zinc and boron showed also significant effect on length of fruit, fruit diameter and average fruit weight. Fruit length (9.3 cm), fruit Table 1. Effect of zinc and boron on plant height of okra Plant height at 45 days after sowing (cm) Plant height at 60 days after sowing (cm) Plant height at final harvest (cm) Mean SE (d) Zn= Zn x 0.87 Zn= 0.19 CD 5% Zn= Zn x 1.77 Zn= Zn x 0.35 Zn x 0.39 Zn= Zn= Zn x 0.75 Zn x Table 2. Effect of zinc and boron on number or branches per plant, first fruiting node and fruit length of okra Number of branches per plant First fruiting node Fruit length (cm) Mean SE (d) Zn= Zn x 0.37 Zn= Zn x 0.54 Zn= Zn x CD 5% Zn= Zn x NS Zn= NS NS Zn x NS Zn= Zn x

3 RESPONSE OF OKRA TO ZINC AND BORON 329 diameter (1.55 cm) and average fruit weight (10.76 g) were measured maximum with treatment combination zinc sulphate 40 kg/ha and borax 15 kg/ha. This increase in fruit size (fruit length, diameter and average weight) might be due to that zinc played an important role in the fundamental processes involved in cellular mechanism. Similarly, boron might have taken part in active photosynthesis and translocation of carbohydrates, which improved the size of fruits (Kumar and Sen, 2005). The results are in corroboration with the results of Reddy et al. (1985) and Yadav et al. (2003) in tomato. Yield characteristics: All the treatments of zinc sulphate and also of borax significantly increased the fruit yield over control. The highest level of zinc sulphate (40 kg/ha) produced the maximum number of fruit per plant (42.57) and fruit yield (89.92 q/ha). The highest dose of borax (15 kg/ha) also gave the maximum fruit number (38.83) and yield (84.48 q/ ha). The interaction of zinc sulphate and borax showed significant effect on fruit number and yield. Among treatment combinations, the application of zinc sulphate and borax at highest level (40 and 15 kg/ha, respectively) produced the highest fruit number (45.20) and yield (93.51), whereas, the minimum fruit number (28.33) and yield (63.13 q/ha) was found with control. In present study, the increase in yield might be due to more vegetative growth, number of fruits per plant and bigger size of fruits. However, according to Reddy et al. (1985) the increased yield per hectare due to the application of micronutrients might be attributed to the favourable effect on flower retention, which might have increased the number of fruits per plant in tomato. Singh and Verma (1991); Kumar and Sen (2005) reported that the increase in yield might be due to more vegetative growth, number and weight of fruit per plant with the application of zinc and boron. Quality characteristics: Soil application of zinc sulphate and borax had significant effect on protein content of okra fruit which increased with increased level of zinc sulphate and borax. The maximum content of protein (17.02%) was found with the highest level of zinc sulphate (40 kg/ha) and boron (15 kg/ha) application in soil independently and in combination (Table 4). The boron and zinc, an essential component of many enzymes are known to be directly involved in the synthesis of protein in plants. Similarly, Singh and Maurya (1979) found that the protein content Table 3. Effect of zinc and boron on fruit diameter, average fruit weight and number of fruits per plant of okra Fruit diameter (cm) Average fruit weight (g) Number of fruits per plant Mean SE (d) Zn= Zn x Zn= Zn x Zn= Zn x 0.29 CD 5% Zn= Zn x Zn= Zn x 0.31 Zn= Zn x 0.58 Table 4. Effect of zinc and boron on fruit yield, protein content and chlorophyll 'a' of okra Fruit yield (q/ha) Protein content (%) Chlorophyll a (mg/g tissue) Mean SE (d) Zn= Zn x 0.79 Zn= Zn x 0.04 Zn= Zn x CD 5% Zn= Zn x 1.60 Zn= Zn x Zn= Zn x 0.041

4 330 KUMAR ET AL. Table 5. Effect of zinc and boron on chlorophyll b, total chlorophyll and zinc content of okra Chlorophyll b (mg/g tissue) Total chlorophyll (mg/g tissue) Zinc content (%) Mean SE (d) Zn= Zn x Zn= Zn x Zn= Zn x CD 5% Zn= Zn x Zn= Zn x Zn= Zn x increased with foliar application of zinc in okra. Ahmed et al. (1987) found an increased content of protein with the application of zinc in tomato fruits. The increased levels of borax increased the chlorophyll content of fruits, however, soil application of zinc sulphate increased the chlorophyll content upto 30 kg/ha, thereafter, it decreased the chlorophpyll content of fruits. Combination of zinc sulphate (30 kg/ha) and borax (15 kg/ha) increased the contents of chlorophyll a (1.89 mg/g tissue) and total chlorophyll (3.05 mg/g tissue) to a maximum since zinc is essential for several enzyme systems that regulate various metabolic activities in plants and it plays an important role in the formation and the activities of chlorophyll. According to Yadav et al. (2003) the increased chlorophyll content might be due to the role of zinc and boron in the synthesis of chlorophyll. However, the decrease in chlorophyll content of fruits at highest zinc level might be due to adverse effect on its synthesis. The maximum content of zinc (0.71%) in okra fruits was recorded with the treatment zinc sulphate 40 kg/ Table 6. Effect of zinc and boron on boron content of okra Boron content (%) Mean Mean SE (d) Zn= Zn x CD 5% Zn= Zn x ha without the application of borax. It might be due to that the higher dose of zinc with increased level of zinc content (Gupta and Hans Raj, 1980) but with increased level of boron, a decrease in the zinc concentration in tomato fruits was also observed (Yadav et al., 2001 & 2003). The okra fruit had maximum boron content (0.64%) with the highest dose of borax (15 kg/ha) and it was also maximum (0.42%) with zinc sulphate 20 kg/ha, which was at par with zinc sulphate 10 and 30 kg/ha. It was recorded maximum in treatment combination zinc sulphate 20 kg/ha + borax 15 kg/ha (0.72%). Boron is found involved in the availability of nitrogen to the plants and synthesis of cell wall components, hence, increasing level of boron increased the boron content in the fruits of okra. Zinc being an essential component of many enzymes and because of playing a major role in the absorption of moisture, its doses up to certain levels might have increased the content of boron in the fruits of okra. Similarly, an increased level of boron increased the boron content, but decreased the zinc contents. Yadav et al. (1999, 2001) showed a contradictory effect of zinc and boron in tomato. Thus, from the results of present study, it is concluded that the maximum increase in yield of okra fruit (52.87%) over control was recorded with soil application of zinc sulphate 40 kg/ha in combination with borax 15 kg/ha. Chlorophyll (a, b and total), zinc and boron contents of immature tender green fruits improved only upto certain levels of zinc sulphate, i.e., 30, 40 and 20 kg/ha and with borax 15, 0 and 15 kg/ha combinations, respectively, thereafter, the applied dose of zinc sulphate and borax had adverse effect on these fruit quality parameters. All growth and yield contributing characters showed strong positive correlation with fruit yield of okra.

5 RESPONSE OF OKRA TO ZINC AND BORON 331 References Ahmed BY, Sharif FM and Sarhan ART (1987). Effect of certain micronutrients on fusarium wilt of tomato. J. Agric., Water Res. and Plant Prod. 6(1): Antil RS, Singh A and Dahiya SS (2002). Practical Manual for Soil and Plant Analysis. Chaudhary Charan Singh Haryana Agricultural University, Hisar, pp Gupta VK and Hans Raj (1980). Effect of source and zinc levels on dry matter, yield and zinc concentration of tomato plants. Haryana J. Hort. Sci. 9(1-2): Hazra P, Maity TK and Mandal AR (1987). Effect of foliar application of micronutrients on growth and yield of okra (Ablemoschus esculentus L.). Progre. Horti. 19(3-4): Jackson ML (1958). Soil Chemical Analysis. Pub. Bentics Hall Inc., New Jersey, USA, p Kumar M and Sen NL (2004). Effect of zinc, boron and gibberellic acid on growth and yield of okra [Ablemoschus esculentus (L.) Moench]. Ann. Agric. Res. New Series. 25(4): Kumar M and Sen NL (2005). Effect of zinc boron and gibberellic acid on yield of okra [Ablemoschus esculentus (L.) Moench]. Ind. J. Hort. 62(3): Naruka IS, Gujar KD and Lal G (2000). Effect of foliar application of zinc and molybedenum on growth and yield of okra [Ablemoschus esculentus (L.) Moench] cv. Pusa Sawani. Haryana J. Hort. Sci. 29(3-4): Reddy P, Suryanarayana R, RamaKrisna MG, Veeraraghavaiah R, Subramanyam K and Reddy DS (1985). Response of tomato to micronutrients. South Ind. Hort. 33: Singh SS and Maurya AN (1979). A note on the effect of zinc application on the growth yield and quality of okra [Ablemoschus esculentus (L.) Moench]. Haryana J. Hort. Sci. 8(3-4): Singh SS and Verma SK (1991). Influence of potassium, zinc and boron on growth and yield of tomato (Lycopersicon esculentum Mill.). Veg. Sci. 18(2): Witnam FH, Blaydes DF and Delivin RM (1971). Experiments in Plant Physiology. Van Nostrand, New York, p Yadav PVS, Singh A and Tikko A (1999). Effect of zinc and boron application on yield of tomato (Lycopersicon esculentum Mill.). Haryana J. Hort. Sci. 28(3-4): Yadav PVS, Tikko A and Sharma NK (2001). Effect of zinc and boron application on yield, concentration and their uptake by tomato (Lycopersicon esculentum Mill.). Haryana J. Hort. Sci. 30(3-4): Yadav PVS, Tikko A and Sharma NK (2003). Effect of zinc and boron application on growth, flowering and fruiting of tomato (Lycopersicon esculentum Mill.). Haryana J. Hort. Sci. 30(1-2):