Influence of Naphthalene Acetic Acid And Cobalt ride on Growth and Yield of Cotton Hybrids.

VEGETOS Vol. 25 (1) : 76-80 (2012) Chlo- Influence of Naphthalene Acetic Acid And Cobalt ride on Growth and Yield of Cotton Hybrids. Rashpal Singh Sarlach * and Bhavna Sharma 1 Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, India 1 Department of Botany, Punjab Agricultural University, Ludhiana, India Field experiment on the effect of NAA and cobalt chloride on yield and its components on cotton hybrids RCH 314 Bt, RCH 134 Bt and their non Bt versions was conducted. Nine treatments included: single spray of 20 µg ml -1 NAA at flower initiation, two sprays of 20 µg ml -1 NAA at 15 days interval starting from flower initiation, single spray of 40 µg ml -1 NAA at flower initiation, two sprays of 40 µg ml -1 NAA at 15 days interval starting from flower initiation, single spray of 10 µg ml -1 cobalt chloride at flower initiation, two sprays of 10 µg ml -1 cobalt chloride at 15 days interval starting from flower initiation, single spray of 15 µg ml -1 cobalt chloride at flower initiation, two sprays of 15 µg ml -1 cobalt chloride at 15 days interval starting from flower initiation. The treatments were sown in a factorial split plot design with three replications. NAA and cobalt chloride significantly increased the partitioning of dry matter to reproductive parts at 150 DAS. Two sprays of 20 µg ml-1 NAA with resulted in highest source sink ratio of 2. 90 as compared to control (1.96) at 150 DAS. Two sprays of NAA @ 20 µg ml-1 with 15 days interval starting from flower initiation gave highest number of bolls per plant (39.44), boll setting percentage (53.86) and boll opening percentage (82.18). The second highest boll number per plant (37.97) was recorded by two sprays of 10 µg ml -1 cobalt chloride with 15 days interval starting from flower initiation. Both these treatments also recorded an increased seed cotton yield of 23.03 q/ha and 22.71 q/ha as compared to control (17.40q/ha. Of the hybrids tested, RCH 134 recorded more yield as compared to RCH 314. Transgenic Bt versions recorded average of 22.29 q/ha seed cotton yield as compared to 18.50 q/ha in the non Bt versions clearly pronouncing the superiority of Bt cotton hybrid. Application of NAA and cobalt chloride did not have any significant effect on quality parameters such as lint percentage, lint index, seed index. Keywords: Bt and non Bt cotton hybrids, naphthalene acetic acid, Cobalt chloride Received: October 7, 2011 Accepted: February 8, 2012 INTRODUCTION Cotton (Gossypium hirsutum L.) known as white gold, is an important commercial crop of national significance because of its immense influence on Indian economy. It contributes about 75 percent of total raw material for textile industry in India and also to foreign exchange earning worth Rs. 60,000 crores to our country. Cotton is considered highly suitable under sub-tropical conditions of Punjab and occupies an area of about 5.30 lakh hectare with a total production and productivity of 16.47 lakh bales & 528 kg/hectare, respectively (Anonymous, 2010-11). Cotton is considered as one of the *Corresponding author email: rssarlach@gmail.com best option for crop diversification on account of its tap root system and exploits the soil profile for water and nutrient enabling the crop with less number of irrigation. It can compete with rice crop provided it gives near optimum yield. Presently, there is a large gap between potential on-station and on-farm cotton yield realization due to indeterminate growth habit and poor management practices. Indeterminate growth habit, leads to excessive vegetative growth, poor partitioning of assimilates towards reproductive structures, greater fruit drop and therefore the genetic potential of the varieties is not realized (Baker, 1976). About 7-35 percent shedding of 76

Influence of N A A and Cobalt chloride on growth and yield of cotton hybrids. flower buds and 42 64 per cent shedding of bolls has been reported due to physiological disorders (Goswami and Dayal, 1998). Different growth regulators are known to regulate various aspects of growth and influence productivity. These have been implicated in translocation, establishment of source sink system and play an important role during fruit and seed development. Plant growth regulators such as Mepiquat Chloride and NAA have been shown to increase the rate of photosynthesis by increasing size of mesophyll cells and chlorophyll contents in leaves of cotton thereby leading to more rapid exchange of CO 2 into mesophyll cell by virtue of their large surface area (Zhao and Oosterhuis, 2000). Sarlach et al (2010) reported that two sprays of 20µgml -1 NAA at flower initiation and 15 days after flower initiation recorded statistically significant higher seed cotton yield than control. NAA increased seed cotton yield by 24.5 per cent over control. NAA also increased the source sink ratio and sympodial branches, boll number per plant and boll setting percentage. Hall et al. (1957) noticed that intact cotton plants did not produce significant amounts of ethylene until the initiation of reproductive stage indicating that squares and young fruits possibly produced significant amounts of ethylene. According to Lipe and Morgan (1973), ethylene, a gaseous hormone is the main cause of premature flower and fruit shedding. Cobalt ion (Co 2+ ) is known to inhibit the biosynthesis of ethylene (Lau and Yang, 1976) by inhibiting the conversion of methionine to ethylene by the higher plants. It has also been reported that the foliar application of cobalt chloride @ 10µg ml -1 controls the parawilt which is also due to excess ethylene production when irrigation and rainfall is received after long dry spell in cotton (Sarlach et al. 2008). Therefore, present study was conducted on the comparative performance of NAA and cobalt chloride on growth and yield of hybrids namely RCH 314 Bt, RCH 134 Bt and their non Bt versions. MATERIAL AND METHODS Field experiment on the effect of NAA and cobalt chloride on yield and its components on hybrids namely RCH 314 Bt, RCH 134 Bt and their non Bt versions was conducted. The nine treatments included:t 0 - control,t 1 - single spray of 20 µg ml -1 NAA at flower initiation, T 2 -two sprays of 20 µg ml -1 NAA at 15 days interval starting from flower initiation,t 3 - single spray of 40 µg ml -1 NAA at flower initiation,t 4 - two sprays of 40 µg ml -1 NAA at 15 days interval starting from flower initiation,t 5 - single spray of 10 µg ml -1 cobalt chloride at flower initiation, T 6 -two sprays of 10 µg ml -1 cobalt chloride at 15 days interval starting from flower initiation,t 7 - single spray of 15 µg ml -1 cobalt chloride at flower initiation,t 8 - two sprays of 15 µg ml -1 cobalt chloride at 15 days interval starting from flower initiation. The treatments were sown in a factorial split plot design with three replications. The data on plant height, dry matter partitioning, internodal distance, monopods, sympods, source sink ratio, bolls/ plant, boll setting, boll weight, halo length, earliness index and seed cotton yield (Table-1), total chlorophyll, GOT, lint index and seed index was taken (Table-2). Total chlorophyll was measured as per the procedure described by Hiscox and Israelstam (1979). Seed cotton yield was worked out on the mean plot yield and expressed in q/ha. Statistical analysis was carried out following the procedure of Panse and Sukhatme (1961) RESULTS AND DISCUSSION The data on plant height (Table-1) reveals no significant difference between RCH 314 and RCH 134, Bt and non Bt hybrids and chemical spray hybrids, type of hybrids and chemical spray. Reproductive structures recorded significant increase in dry matter accumulation, highest value being recorded by two sprays of 20µg ml -1 NAA (122.34 g/plant) followed by two sprays of 40 µg ml -1 NAA (107.85g/plant). Kumar et al 2006 also recorded maximum fruit dry weight among the treatments with NAA at 150 days after sowing. More dry matter partitioning to fruiting bodies with NAA may be result of its favorable effect on the development and retention of fruiting bodies. Among hybrids RCH 134 (100.72g/plant) was better than RCH 314 (96.30 g/plant) in dry matter accumulation in reproductive parts. Maximum dry matter accumulation in stem (48.93 g/plant) was recorded by single spray of 15µg ml -1 cobalt chloride Chemical sprays did not show any significant increase in internodal distance (Table-2) from control, however, maximum internodal distance (2.87 cm) was recorded in single spray of 20µg ml -1 NAA followed by two spray of 20µg ml -1 NAA (2.84cm). Among the hybrids RCH 134 recorded mean internodal difference of 2.88 cm as compared to RCH 314 (2.56 cm) Among hybrids and type of hybrid, the difference in respect of internodal distance was non significance. This could be due to the fact that monopods developed from lower node during early stage of development but application of chemicals was made at later stage of growth. The highest mean monopodial branches (1.50) observed in one spray of 20µg ml -1 NAA treatment was at par with single spray of 20µg ml -1 NAA. Chemical spray s positively affected the number of sympodial branches per plant with maximum mean of 33.53 recorded by two sprays of 10µg ml -1 cobalt chloride followed by two sprays of 15µg ml -1 Cobalt chloride (30.33), single spray of 10µg ml -1 cobalt chloride (29.33), two sprays of 20µg ml -1 NAA treatment (29.00). Among the type of hybrid the difference was non significant. Among hybrids RCH 134 was better than RCH 314 in respect of sympods. The increase in number of sympodial branches due to NAA and cobalt chloride could be due to their favorable effect on the growth of the plant. These results were corroborated with the finding of Kaur 2008 where two sprays of 20µg ml -1 NAA increased the sympodial branches per plant. All the sprays significantly affected the source sink ratio. The highest mean source sink ratio of 2.90 was recorded in two spray of 20µg ml -1 NAA treatment and least in single spray of 10µg ml -1 cobalt chloride. Further data revealed that among hybrids RCH134 had more source sink ratio (2.68) 77

R S Sarlach and Bhavna Sharma Table 1. Comparative performance of Bt and non Bt hybrids in respect to plant height, dry matter partitioning, internodal distance, monopods, sympods, source sink ratio, bolls per plant, boll setting, boll weight, halo length, earliness index and seed cotton yield in response to hybrids, type of hybrids and chemical treatment Pl ht (cm) Dry Matter Partitioning (g/plant) (A) Hybrids Stem leaves Rep. str Internodal distance (cm) Mon opod s (No) Symptoms (No) Source sink ratio Bolls/ plant Boll setting (%) Boll wt (g) Halo length Earliness index RCH 314 82.15 39.95 48.29 96.30 2.56 1.47 25.90 2.10 32.49 48.42 3.32 24.86 0.91 19.96 SCY (q/ha) RCH 134 87.12 39.68 39.62 100.72 2.88 1.26 30.35 2.68 34.07 48.13 3.41 24.51 0.90 20.83 CD at 5% NS NS 1.03 3.64 0.27 NS 2.08 0.20 NS ns ns ns ns ns (B) Type of hybrids Bt 82.80 41.62 44.21 98.93 2.56 1.35 29.14 2.39 37.6 51.71 3.29 24.60 0.89 22.29 Non Bt 86.47 38.00 43.69 98.10 2.88 1.37 27.10 2.39 29.0 44.84 3.43 24.77 0.91 18.50 CD at 5% NS 2.68 NS NS 0.27 NS NS NS 3.91 4.24 ns ns ns 0.88 (C) Chemicals sprays (Control) 82.58 31.87 45.10 85.35 2.61 1.33 24.08 1.96 25.56 42.77 3.29 24.53 0.91 17.40 *NAA 20µg ml -1 84.20 37.97 42.98 90.71 2.87 1.50 26.53 2.39 32.31 48.27 3.47 23.89 0.88 19.18 **NAA 20µg ml -1 88.86 46.58 44.33 122.34 2.84 1.50 29.00 2.90 39.44 53.86 3.22 24.78 0.91 23.03 *NAA 40µg ml -1 85.28 45.32 42.96 97.10 2.68 1.08 26.92 2.39 30.42 45.50 3.32 25.08 0.91 17.53 **NAA 40µg ml - 80.67 39.25 44.99 107.85 2.66 1.42 27.34 2.70 32.55 48.56 3.60 25.45 0.89 20.83 *CoCl2 10 µg ml -1 87.72 41.55 48.35 100.27 2.80 1.25 29.33 2.10 32.36 47.78 3.23 24.61 0.90 19.74 **CoCl2 10 µg ml -1 82.61 32.48 43.42 96.81 2.60 1.42 33.53 2.38 37.97 51.27 3.48 24.53 0.92 22.71 *CoCl2 15 µg ml -1 86.67 48.93 41.41 91.36 2.81 1.33 26.06 2.20 32.36 46.33 3.33 24.78 0.91 20.19 **CoCl2 15 µg ml -1 83.14 34.36 42.04 94.84 2.63 1.42 30.33 2.45 36.56 50.25 3.31 24.53 0.89 22.95 CD at 5% NS 5.52 3.87 5.68 NS NS 2.56 0.37 4.33 5.16 NS NS NS 1.75 *Single spray at flower Initiation ** Two sprays with15 days interval starting from flower Initiation 78

Influence of N A A and Cobalt chloride on growth and yield of cotton hybrids. Table 2. Comparative performance of Bt and non Bt cotton hybrid in respect of total chlorophyll contents and quality parameters in response to hybrids, type of hybrids and chemical spray Treatments Total chlorophyll (mg chl g -1 fresh weight) Total chlorophyll (mg chl g -1 fresh weight) GOT Lint index Seed index (g) Flower initiation 50% Boll opening stage (%) (g) 100 seed weight (A) Hybrids RCH 314 1.57 1.69 35.38 5.01 9.12 RCH 134 1.57 1.03 37.09 5.39 9.12 CD at 5% NS 0.03 0.90 0.26 NS (B) Type of hybrids Bt 1.57 1.53 35.94 4.98 8.86 Non Bt 1.59 1.18 35.53 5.42 9.39 CD at 5% NS 0.03 NS 0.26 0.23 ( C) Chemical sprays (Control) 1.59 1.31 36.46 2.53 9.29 *NAA 20µg ml -1 1.62 1.37 35.90 5.12 9.13 **NAA 20µg ml -1 1.68 1.41 36.38 5.19 9.05 *NAA 40µg ml -1 1.70 1.24 36.24 5.24 9.19 **NAA 40µg ml - 1.50 1.34 36.86 5.36 9.17 *CoCl2 10 µg ml -1 1.52 1.37 36.51 5.20 9.03 **CoCl2 10 µg ml -1 1.62 1.43 35.62 5.00 9.00 *CoCl2 15 µg ml -1 1.55 1.43 35.80 5.07 9.07 **CoCl2 15 µg ml -1 1.47 1.32 36.64 5.27 9.20 CD at 5% 1.09 0.03 NS NS NS *Single spray at flower Initiation ** Two sprays with15 days interval starting from flower Initiation than RCH 314 (2.10). Among Bt and non Bt, the differences were non significant. In cotton boll numbers per plant and boll weight primarily influence the seed cotton yield since these are cardinal yield components showing direct and indirect association with seed cotton yield (Ismail and Erani 1986). The maximum increase was found in two sprays of 20µg ml -1 NAA (39.44) followed by two sprays of 10µg ml -1 cobalt chloride (37..97). Application of NAA might have increased the reducing sugars content of reproductive parts for the development of flowers and bolls, met out the heavy demand for carbohydrates and ultimately prevented the boll shedding.. Cobalt chloride acted as ethylene inhibitors, thus preventing the abscission of bolls. Among hybrids the differences were non significant. Among type of hybrids, Bt (37.6) performed significantly better than non Bt (29.0). Koler et al 2010 reported that NAA @30 ppm, 20 ppm and 10 ppm recorded increased yield due to higher seed cotton yield per plant, more number of bolls and boll weight. Boll setting is one of the important parameter affecting the seed cotton yield.. The maximum boll setting (53.86) was noticed in two sprays of NAA @ 20µg ml -1. Two sprays of cobalt chloride @10µg ml -1 and 15µg ml -1 gave boll setting percentage of 51.27 and 50.25 respectively which were at par with two sprays of 20µg ml -1 NAA. A single spray of 40µg ml -1 NAA gave the least setting percentage of 45.50 as compared to other treatments. Among the type of hybrids Bt gave significant higher mean boll setting of 51.71 as compared to non Bt (44.84). Similarly, Sharma and Dungarwal (2003) noticed more squares, flowers, number of picked bolls, total number of boll per plant and boll setting percentage with the application of NAA and triacontenol. In the present study two foliar application of 20µg ml -1 NAA improved boll setting by 25 per cent over no spray. The data on seed cotton yield revealed that there was non significant difference in the yield of hybrids (RCH134 and RCH 314). But RCH 134 gave more yield as compared to RCH 314.Among Bt and non Bt, results were found highly 79

significant. The Bt cotton hybrid gave 22.29q/ha seed cotton yield as compared to 18.50q/ha in non Bt clearly pronouncing the superiority of Bt cotton hybrid. There was difference of 3.70 q/ha which was of high economic value. The increased seed cotton yield in Bt cotton hybrid might be attributed to better fruiting efficiency and more number of picked boll per plant which ultimately reflected in seed cotton yield. So for the effect of chemicals on productivity was concerned, the application of two sprays of 20µg ml -1 NAA gave maximum seed cotton yield (23.03q/ha) which was found at par with two sprays of 10µg ml -1 cobalt chloride (22.71q/ha) and 15µg ml -1 cobalt chloride (22.95q/ha) and significantly more than the rest of treatments. It is astonishing to note the chemical did respond favorably when two sprays were given with 15 days interval starting from flower initiation. These results are corroborated with the findings of Sawan et al 1989 they reported that seed cotton yield per plant was significantly increased with most of the NAA levels. The highest yield was obtained with 20 ppm and the three sprayings proved to be moist effective, followed by twice and then once. Katkar et al (2002) concluded that the spraying of cobalt chloride 2.0 milli molar recorded significantly higher seed cotton yield by 21.2 per cent over control. Interaction effect of type of hybrid and chemical sprays on yield revealed that yield of Bt cotton was highest under two sprays of 20 NAA (26.756q/ha), however on non Bt it was highest (20.47q/ha) with two sprays of 10µg ml -1 and 15 µg ml -1 cobalt chloride, therefore, yield of Bt cotton was significantly more than non Bt at each treatment. The data on total chlorophyll, GOT, lint index and seed index is given in Table2. Among the treatments, two sprays of NAA @ 20µg ml -1 gave highest significant difference in respect of total chlorophyll contents (1.68) which was at par with one spray on 40µg ml -1 NAA (1.70) at flower initiation stage, as compared to control (1.59). Among hybrids and type of, there was non-significant difference at flower initiation stage. At 50% boll opening stage, among the treatments, the maximum total chlorophyll contents was recorded with two sprays of 20µg ml -1 NAA (1.41) and one spray of 10µg ml -1 cobalt chloride (1.43) and single spray of 15µg ml -1 cobalt chloride (1.43). Among the type of hybrids, Bt hybrid retained more total chlorophyll contents (1.53) at 50% boll opening stage than non Bt (1.18). There was non significant difference in respect of boll weight, halo length, earliness index, ginning out turn, lint index and seed index were recorded among hybrids, type of hybrids and treatments. Among the treatments two sprays of NAA @20µg ml -1 and 10µg ml -1 cobalt chloride increased the number of bolls per plant, total chlorophyll contents and dry matter partitioning and seed cotton yield. Transgenic Bt versions recorded average of 22.29 q/ha seed cotton yield as compared to 18.50 q/ha in the non Bt versions clearly pronouncing the superiority of Bt cotton hybrid. Application of NAA and cobalt chloride did not have any significant effect on quality parameters R S Sarlach and Bhavna Sharma such as lint percentage, lint index, seed index. REFERENCES Anonymous (2010-11). Annual progress report for All India Coordinated Cotton Improvement Project, Central Institute for Cotton Research Coimbatore. A3-A4 Baker S H (1976). Response of cotton to row patterns and plant population. Agron J 68: 85-88. Goswami C L and Dayal J (1998). Nutritional and hormonal aspect of boll shedding in cotton. 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