ABSTRACT
The combined effect of different rates of fertilizer (N + P) and concentrations of a growth regulator commercial product on growth and yield of cotton was studied. There were two types of treatments viz. fertilizer rates (F) and Mixtalol concentrations (M) placed randomly in the field under split-splot design with four replications. Main-plot treatments were: Fo Control/no fertilizer), F1 (half rate of recommended N and P fertilizers viz. 575 and 28.8 kg ha-1, respectively) and F2 (full rate of recommended N and P fertilizers viz. 115 and 57.5 kg ha-1, respectively). The sub-plot treatments included: Mo (Control/no Mixtalol Spray), M1 (2 pm Mixtalol sprays thrice) and M2 (3 ppm Mixtalol spray thrice). Thus there were nine treatments combinations in total. Data on plant height and number of branches per plant showed significantly increased values of these two with the both doses of fertilizer as well as Mixtalol over Control. The difference between M1 and M2 was non significant for both parameters, while the F1 and F2 gave statistically similar values for number of branches and F2 was superior to F1 with respect to plant height. The best combination was F2 x M1 and the lowest values were found in Fo x Mo. As regards the number of bolls per plant and seed cotton yield, F2 gave statistically better results than did F1 and F2. among Mixtalol treatments M1 performed better than M2. the synergistic effect was best with F2 x M1 and it was lowest at Fo x Mo. Thus it was concluded that cotton gave the highest response to full rate of fertilizer (F2) along with lower concentration (2 ppm) sprays Mixtalol (M1) as the most suitable combination.
PDF Abstract XML References Citation
How to cite this article
DOI: 10.3923/ajps.2003.974.977
URL: https://scialert.net/abstract/?doi=ajps.2003.974.977
INTRODUCTION
The growth of cotton, like all other plants, is a complex process and is the net result of all the physiological phenomena which are controlled by the interactive reactions between their genetic make up and environments comprising climatic, edaphic and the nutritive factors. The nutritive factors include macronutrients and growth regulators.
Cotton is the white gold of Pakistan occupying the second largest area (2.96 m ha) of all the crops grown in Pakistan (GOP, 1999). Cotton based exports earn nearly 60% of the countrys foreign exchange and cotton seed accounts for about 72% of the domestic edible oil production (Khan, 1999). In spite of this much significance of cotton to Pakistan, its per hectare yield is very low viz. 1580 kg ha-1, which is even less than the world average and far below than the yield in cotton growing countries (FAO, 1997). One of the factors for low yield is the declining soil fertility as reflected by the increasing consumption of chemical fertilizers every year. Even the higher doses of nitrogen (N) and phosphorus (P) fertilizers did not enhance the crop yields significantly.
Under this situation, the use of growth regulators in combination with fertilizers seems to bear prospects to enhance crop yields. Five different types of plant regulators viz. auxins, gibberellins, cytokinins, indole acetic acid (IAA) and ethylene are recognized. They are known to influence the rooting, seed germination, flowering, fruit setting and development, plant size, tillering and environmental stresses. In cotton, there was an increase in the number of bolls per plant through GA3 application (Sawan et al., 1989) and increase in the cotton yield through Pix (mepiquat chloride) application (Pol and Thombre, 1985) and by seed soaking in GA3 (Eid and El-Aggory, 1985). Similarly, Zheng and Zu (1982) reported that exogenous application of IAA in cotton stimulated growth and decreased boll shedding. Sawan et al. (1989) observed that higher rate of N and P on cotton sprayed with IAA, IBA and NAA gave increased seedling vigour/length and seed cotton yield. Similar are the findings of Fan et al. (1990) through application of N fertilizer and mepiquat to cotton.
In Pakistan, (Jalis and Chaudhry, 1997) and in India (Chaudhri and Bathkal, 1977) got increased seed cotton yield with the spray of Planofix (NAA) to cotton.
The present experiment was planned to study the effect of spraying Mixtalol a growth regulator product marketed by Lever Brothers Pakistan Ltd., on cotton in addition to different levels of N and P fertilizers application. It is claimed to enhance seed germination, vegetative and reproductive growth of crop contributing favorably to increase the productivity potential. In a field trial with Mixtalol-fertilizer interaction on cotton, plant height, number of branches and bolls per plant and seed cotton yield were significantly increased, by Mixtalol foliar spray (Saeed et al., 1986).
MATERIALS AND METHODS
The study was undertaken at University of Agriculture, Faisalabad on cotton CV. B-557 as a test variety. This field experiment was laid out according to split-plot design with four replications. Each sub-plot had a dimension of 8 m x 3 m (24 m2). The treatments were as below.
Main-plot treatments = Fertilizer rates (F):
Fo | = | Control (no N and P fertilizer) |
F1 | = | Half rate of N and P fertilizers viz. 57.5 and 28.8 Kg ha-1 N and P2O5, respectively. |
F2 | = | Full rate of N and P fertilizers viz. 115 and 57.5 Kg ha-1 N and P2O5, respectively. |
Sub-plot treatments = Mixtalol concentrations (M):
Mo | = | Control (no Mixtalol spray but only water). |
M1 | = | Mixtalol @ 2 ppm in foliar spray. |
M2 | = | Mixtalol @ 3 ppm in foliar spray. |
Phosphatic fertilizer DAP was whole applied at the time of land preparation before sowing and N fertilizer Urea was applied just before first irrigation. The Mixtalol foliar sprays were done thrice, first at 15 days after sowing, on 10th June, second on 12 July and third on 12th August with Solo Knop Sack hand spray pump. All the other agronomic and plant protection measures were applied equally to all the treatments. Data regarding growth and yield parameters were recorded during the crop duration. Data were analyzed statistically through Analysis of Variance (ANOVA) technique (Steel and Torrie, 1982) and the treatments were compared by Duncans Multiple Range Test (Duncan, 1961).
RESULTS AND DISCUSSION
Plant height: Data regarding the effect of different rates of N and P fertilizers, Mixtalol concentrations and the interaction of fertilizer with Mixtalol are given in Table 1. It indicates that maximum plant height was under F2 (full rate of fertilizer), which was statistically significant over that of F1 (half rate of fertilizer), which was superior to Fo (Control). Among Mixtalol treatments, M1 (2 ppm) and M2 (3 ppm) caused statistically equal plant height, however both concentrations gave statistically higher value than that of Mo (Control). Results of this study show that Mixtalol foliar spray causes increase in the plant height of cotton, however, both the concentrations have non significant difference, although the M2 (higher concentration) caused smaller increase in plant height. Misra and Malik (1980) also recorded an increased plant height of cotton through foliar spray of 0200 ppm Cycocel (Chloromequat), but it was less at increasing concentrations. In contrast, Kerby (1983) and Cathey (1984) observed that application of Pix (mepiquat chloride) and triacontol, respectively, to cotton reduced the plant height.
The interaction of fertilizer and Mixtalol (F x M) revealed that the maximum plant height was under F2 x M1 and F2 x M2 both being statistically similar. The lowest values were recorded under Fo x Mo, Fo x M2 and F1 x Mo which had non significant difference among themselves. This reveals that F2 (full fertilizer) along with M1 (2 ppm Mixtalol) gives the maximum plant height, where as in the absence of both viz. Fo x Mo, the plant height is minimum. Similar results were obtained by Saeed et al. (1986) who observed in a field trial with Mixtalol-fertilizer interaction on cotton that plant height was significantly increased. However, McConnell et al. (1992) found decreased plant height with mepiquat chloride.
Number of branches: Table 2 presents the data on number of branches per plant as influenced by the application of fertilizers and Mixtalol. The average results show the positive effect of the both, however, the differences between half and full rate of fertilizer and that between Mixtalol concentrations viz. 2 ppm and 3 ppm were statistically non significant. Among the interactions of both type treatments (F x M), the best results were obtained by F2 x M1 (full fertilizer x 2 ppm Mixtalol) and the lowest value was in control viz. Fo x Mo. Misra and Malik (1980) also found increased number of branches of cotton plant through foliar spray of Cycocel. Similar results were recorded by Saeed et al. (1986) with Mixtalol x fertilizer applications to cotton.
Number of bolls: Total number of bolls per plant were directly affected by fertilizer application being highest number under F2 (full fertilizer), which was statistically superior to F1 and Fo (Table 3). Mixtalol gave highest value at M1 (2 ppm) which was significantly better than that with M2 (3 ppm). The interaction of F x M gave best results under F2 x M1 followed by F1 x M1. increased number of bolls per plant were also observed by Khan and Hanif (1980) through spray of 20 ppm NAA /acre. Sawan et al. (1981) got similar results with IBA spray, while Kerby (1983) had same experience with Pix application. Higher number of bolls were also obtained by GA3 application (Eid and El-Aggory, 1985), NAA and IAA application (Tanveer et al., 1986) and Mixtalol fertilizer interaction (Saeed et al., 1986).
Table 1: | Effect of fertilizer and Mixtalol application on cotton plant height |
Table 2: | Effect of fertilizer and Mixtalol application on cotton branches (# plant-1) |
Table 3: | Effect of fertilizer and Mixtalol application on cotton bolls (# plant-1) |
Table 4: | Effect of fertilizer and Mixtalol application on seed cotton yield (t ha-1) |
Seed cotton yield: The results of fertilizer and Mixtalol application are similar on seed cotton yield (Table 4) as stated for number of bolls. The best combination of F x M was F2 x M1 followed by F2 x M2, however, both have statistically significant difference and the lowest value was under Fo x Mo. A number of scientists working on different growth regulators found increased seed cotton yield through application of NAA (Jalis and Chaudhry, 1977; Chaudhry and Bathkal, 1977; Fan et al., 1990), IAA, IBA and NAA (Sawan et al., 1989), GA3 (Eid and El-Aggory, 1985) and Pix (Pol and Thombre, 1985). Mixtalol-fertilizer interaction was studied by Saeed et al. (1986), they got exactly the same results as recorded in the present study. In contrast McConnell (1992) reported decreased cotton yields with the application of mepiquat chloride.
Cotton gave best response to the application of full dose of fertilizer even in the presence of Mixtalol treatment. The Mixtalol sprays gave maximum growth and yield of cotton at lower concentration viz. M1 (2 ppm), whereas, higher dose viz. M2 (3 ppm) got smaller response of cotton. Therefore, the most suitable combination of fertilizer-Mixtalol was the F2 x M1 viz. full fertilizer along with 2 ppm Mixtalol spray thrice starting from 15 days after sowing with one month interval between each application.