On optimum plot size and shape for field experimentation on brinjal (Solanum melongena L.) under middle Gujarat condition

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1 Volume 5 Issue 2 September, e ISSN International Research Journal of Agricultural Economics and Statistics Visit Us - DOI : /HAS/IRJAES/5.2/ Research Paper On optimum plot size and shape for field experimentation on brinjal (Solanum melongena L.) under middle Gujarat condition M.S. SHITAP AND V.B. DARJI See end of the paper for authors affiliations Correspondence to : M.S. SHITAP Department of Agriculture Statistics, B.A. College of Agriculture, Anand Agricultural University, ANAND (GUJARAT) INDIA Paper History : Received : ; Revised : ; Accepted: ABSTRACT : An uniformity trial on JBGR-1 of brinjal was conducted at the Main Vegetable Research Station, Anand Agricultural University, Anand to determine the optimum size and shape of the plot using maximum curvature method. The variability as judged by co-efficient of variation (CV) per unit area decreased with the increase in plot size. The optimum plot (net) size obtained and advocated was 6.48 sq. m. covering single row of 7.2 m length and spaced at.9 m (7.2 m.9 m) for field experiments on brinjal under Anand condition. KEY WORDS : Plot size, Shape, Field experiment Brinjal HOW TO CITE THIS PAPER : Shitap, M.S. and Darji, V.B. (214). On optimum plot size and shape for field experimentation on brinjal ( Solanum melongena L.) under middle Gujarat condition. Internat. Res. J. Agric. Eco. & Stat., 5 (2) : INTRODUCTION Brinjal (Solanum melongena Linn.) belongs to the family Solanaceae. Brinjal is popular vegetable and is native of India. In India, major brinjal producing states are Orissa, Bihar, Karnataka, West Bengal, Andhra Pradesh, Maharashtra and Uttar Pradesh (Anonymous, 24). It can be grown throughout the year it almost all the states of India except at higher altitudes. The varieties of Solanum melongena L. show a wide range of fruit shapes and colors, ranging from oval or egg-shaped to long club shaped; and from white, yellow, green through degrees of purple pigmentation to almost black. Choice of suitable size and shape of plot is the basic requirement of field experiments. Reliability of the results of such field experiments depends on the amount of experimental error which is usually expressed in terms of co-efficient of variation (CV). Soil fertility variation is the prime source of experimental error (Fisher, 1935 and Federer, 1955) which is also influenced by the experimental factors such as size and shape of experimental units (plots), block size, number of replications, number of treatments, experimental designs etc. (Panse and Sukhatme, 1978). Patel and Patel (1968); Prajapati (1981); Patel et al. (1985); Ramani (199); Bhatt (1993); Anonymous (1996) and George (1986) have worked on the optimum plot size for various crops at Anand, Gujarat. But for brinjal, the main vegetable crop of the zone, such information is yet lacking. The present study, therefore, was undertaken to investigate the optimum plot size as well as shape for field experimentation on brinjal crop. MATERIALS AND METHODS A uniformity trial on brinjal crop was conducted at Main Vegetable Research Station, Anand Agricultural University, Anand to workout optimum size and shape of plot. The high yielding variety JBGR-1 was sown at a spacing of 9 cm 6 cm covering an area of approximately 35 sq. m. All the cultural

2 M.S. SHITAP AND V.B. DARJI practices in vogue were followed. Picking-wise fruit yield data of individual plant (basic unit) were recorded. There were 63 plants (basic units) under study. Yield data were recorded for 1 pickings which accounted for more than 95 per cent of total fruit yield. The co-efficient of variation (CV) per unit area in per cent for all possible combinations of different plot sizes and shapes were calculated using the following relation : CV% = Standard deviation per unit area General mean X1 For estimating co-efficient of variation per unit area in per cent, the variance V(x) among plots of all possible sizes were calculated using the relation V (x) Sum of squres of a given size = Degreesof freedom (n - 1) Thereafter, to get variance per unit area Vx, the V(x) was divided by the square of plot size, i.e. number of basic units involved in formation of that plot size. Thus, V(x) Vx = 2 X The optimum plot size was taken as the point of curve just beyond the point of maximum curvature (Day,192 and Federer, 1955). The CV per cent (hereafter CV) was plotted against plot size. RESULTS AND DATA ANALYSIS The findings of the present study as well as relevant discussion have been presented under the following heads : Optimum plot size : The CV estimated for 25 sizes and 51 shapes are presented in Table 1. The results (Table 1) revealed that the maximum coefficient of variation was observed in the smallest sized plots i.e. one unit in all pickings as well as total yield and it decreased with the increase in plot size. On an average basis, the maximum CV was observed in the second picking (21.22) followed by first picking (19.58) and seventh picking (18.29). The lowest average CV was found in the sixth picking (13.52), next in line was fifth picking (13.66). The average CV over ten pickings ranged from per cent for one unit to 7.51 per cent for 6 units plot (3 2). The average CV over size of plot ranged from per cent for one unit to 7.71 per cent for 6 units plot. The CV decreased with the increase in plot size. Nonnecke (196), Iyer and Aggarwal (197), Prajapati (1981), Ramani (199), Igue et al. (1991), Bhatt (1993) and Shafi et al. (21) also reported similar trend. C V % Fig. 1 : CV % O b s e rve d va lue Fig. 2 : C V % P lo t S iz e ( U n it s) P re d ic te d va lue Observed and predicted CVs for average over plot size. Observed value Fig. 3 : Plot Size (Unit) Predicted value Observed and predicted CVs for total yeild. O bs erved value P redic ted value P lo t S iz e (U n it) Observed and predicted CVs for second picking. The per unit decrease in CV ease in locating point of maximum curvature. These estimates were calculated for second picking (showing maximum variation), total yield (i.e. sum of fruit yields of 1 pickings which yielded minimum CV and average over plot size. The results (Table 2 and Fig. 1, 2 and 3) revealed that the per unit decrease in CV was observed up to 9 units in case of second picking and it was up to 1 units in case of average over plot size and total yield. Thereafter the per unit decrease in CV was not proportional to the area added in forming the large sized plots barring 15 units size in second picking and average over plot size and 18 and 21 units size plots in second picking. On overall basis and due weightage to total yield, 1 units size was considered as an optimum point and the plot size just adjacent to 1 units i.e. 12 units size was taken as optimum plot size for field experimentation on brinjal 149

3 ON OPTIMUM PLOT SIZE & SHAPE FOR FIELD EXPERIMENTATION ON BRINJAL Table 1: Co-efficient of variation per unit area (size) in per cent for fruit yield of brinjal Plot Plot shape Picking number size Total Average over U L W yield 1 pickings Plot size * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Average * indicates of significance of values at p=.1, respectively U indicates number of unit(s) in that size of plot; L indicates length in unit(s) in that size of plot; W indicates width in unit(s) in that size of plot 15

4 M.S. SHITAP AND V.B. DARJI crop. Plot shape : The data presented in Table 1 brought out the fact that the increase in width of the plot, increased variability (CV), probably due to fertility variation. The variance estimates for all the pickings as well as total yield for various combinations (shapes) were thus tested by Bartlett s test of homogeneity of variances. Results obtained through this test were same in all pickings and total yield. The summarized results are presented in Table 3. The information (Table 3) revealed that the variance estimates for combinations (shapes) of plot size(s) were heterogeneous for all plot sizes barring plot shapes of 2 and 3 units size plot for all pickings and total yield. Among all the combinations of 12 unit size plots, Table 1 provides information for 6 2 and 3 4 combinations but not for 12 1, 4 3, 2 6 and 1 12 combinations. Therefore, CV values were generated using randomly chosen four sets each of size (N = 144) from the experimental area of 3 21 Table 2 : Per unit decrease in CV Plot size Second picking Total yield Average over plot size CV Per unit decrease CV Per unit decrease CV Per unit decrease Table 3: Test of homogeneity of variances for various combinations of plot size(s) Plot size Test Plot size Test Plot size Test ** 21 ** 3 NS 9 ** 3 ** 4 ** 1 ** 4 ** 5 ** 12 ** 42 ** 6 ** 15 ** 5 ** 7 ** 2 ** 6 ** Legend: NS: not significant i.e. homogeneity between variances ** indicates of significance of values at p=.1, respectively 151

5 ON OPTIMUM PLOT SIZE & SHAPE FOR FIELD EXPERIMENTATION ON BRINJAL Table 4: CV for various shapes of 12 units sized plot (n = 144) Picking Set Total yield I II III IV Average Second I II III IV Average Overall average size (N = 63) and the results so obtained are presented in Table 4. Among all the combinations of 12 unit size plots (Table 1 and 4), a plot of 12 1 unit shape (single row plot) had minimum CV (1.45 %) and the next in line was 4 3 shape. The 12 units size plot having 12 units length (7.2m) and one unit width (.9 m) i.e. 7.2 m.9 m = 6.48 m 2 as net plot size can be considered as an optimum size and shape for field experiments on brinjal. Conclusion : Based on uniformity trial on brinjal crop (Cv JBGR-1) the plot size of 7.2 m.9 m = 6.48 sq. m. as net size was advocated for field experimentation. Authors affiliations: V.B. DARJI, Department of Agricultural Statistics, B.A. college of Agriculture, Anand Agricultural University, ANAND, (GUJARAT) INDIA. LITERATURE CITED Anonymous (1996). Annual report. Department of Agricultural Statistics, B. A. College of Agriculture, Anand Agricultural University, ANAND, GUJARAT (INDIA). Anonymous (24). Report of the Ad Hoc technical Expert Group in Forest Biological Diversity. (UNEP/CBD/SBTTA/7/6). Anonymous, Food an Agricultre Organization, Production Year book, 54: Bhatt, H.M. (1993). Plot technique in potato ( Solanum tuberosum L.). M.Sc. Thesis. Gujarat Agricultural University, SARDARKRUSHINAGAR, GUJARAT (INDIA). Day, J.W. (192). The relation of size, shape and number of replications of plots to probable error in field experiments. J. Amer. Soc. Agron., 12: t h Year of Excellence Federer, W.T. (1955). Experimental desingns. The MacMillin Co., New York. : Fisher, R.A. (1935). The design of experiments. Edinburgh: Oliver and Boyd. George, K.C. (1986). Optimum size and shape of plots for field experiments in brinjal. Agric. Res. J. Kerala, Igue, T., Espironelo, A., Cantarella, H. and Nelli, J. (1991). Plot size and shape for sugarcane experiments. Bragantia, 5(1): Iyer, S.S. and Agrawal, K.C. (197). Optimum size and shape of plots for sugarcane. Indian J. Agri. Sci., 4: Nonnecke, I.L. (196). The precision of field experiments with vegetable crops as influenced by plot and block size and shape. Can. J. Plant Sci., 4: Panse, V.G. and Sukhatme, P.V. (1978). Statistical methods for agricultural workers. ICAR Publication, Ministry of Agriculture, NEW DELHI (INDIA) Patel, N.M. and Patel, R.M. (1968).Plot technique in Bajri (Pennisetun typhoides S & H.). B. A. Col. Mag.: Patel, N.M., Patel, R.B. and Patel A.S. (1985). Plot size studies in Forage Oat under two methods of irrigation. GAU. Res. J., 1(2): 5-9. Prajapati, B.H. (1981). Plot size study in bidi tobacco ( Nicotiana tabacum L.). M.Sc. Thesis. Gujarat Agricultural University, SARDARKRUSHINAGAR, GUJARAT (INDIA). Ramani, C.V. (199). Plot technique in lucerne. M.Sc. Thesis Gujarat Agricultural University, SARDARKRUSHINAGAR, GUJARAT (INDIA). Shafi, S., Mir, S.A., Nazir, N. and Rashid, A. (21). Optimum size for tomato by using S-PLUS and R-software s in soils of Kashmir. Asian J. Soil Sci., 4(2):