| Path analysis in wheat under different sowing dates
B. K. JADAV and B. S. JADON Gujarat Agricultural University Junagadh, Gujarat, India With the improvement in the production technology in agriculture, different crop rotations are being advocated in order to increase cropping intensity and thereby total agriculture production. Varieties wih specific characteristics are needed for a particular crop rotation which can yield more under given set of production conditions. The knowledge of genetic association between grain yield and its components under different production conditions will improve the efficiency of breeding programme by preparing appropriate selection indices for developing suitable varieties. Though, studies on path coefficient in wheat have been made but such studies under different sowing times are scanty. The present study was, therefore, planned to achieve a clear picture of the inter-relationship with grain yield of various components and developmental traits under early, timely and late sowing. The direct and indirect effects were worked out using path analysis at genotypic level. Materials and Methods One hundred diverse wheat varieties selected from different wheat growing zones of the country including exotics and lines from CIMMYT were grown in randomized block design with three replications on 5 October (early), 15 November (timely) and 15 December (late). 3.5 meter long row plot was randomly assigned to each variety. Distances between row to row was 30 cm and plant to plant within row being 10 cm. Recommended cultural practices were followed uniformly to raise the good crop. Five random comptitive plants were selected from each plot for observations on days to flowering, days to maturity, peduncle length, plant height, tillers/ plant, grains/spike, grain weight/spike, 1000 grain weight, grain yield/plant and harvest index. Genotypic and phenotypic correlation coefficients were calculated using the formula suggested by Miller et al. (1958). Direct and indirect effects of component characters on grain yield were worked out using path coefficient analysis (Dewey / Lu, 1959). Results and Discussion The analysis of variance in early, normal and late sowing revealed significant differences amongst genotypes for all the characters. The phenotypic and genotypic correlation coefficients between grain yield an its components were computed for early, timely and late sowing. All the characters under study showed significant positive correlation with grain yield except harvest index under normal and plant height under late sowing. The direct and indirect effect of each character on grain yield are presented in Table 1. The path analysis in early sowing indicated that tillers/plant and grain weight/spike had high positive direct effect on grain yield/plant. The indirect effect of all characters on grain yield via tillers/plant and grain weight/spike was also of high positive magnitude. The plant height had positive direct and indirect effect of moderate magnitude. Whereas, Days to maturity, peduncle length and 1000 grain weight had negative direct and indirect effects except indirect effect of 1000 grain weight through plant height. The magnitude of positive direct effect of days to flowering and negative direct effect of grains/spike and harvest index was low. |
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