| Multiple correlation and partial regression Detailed information on the effectiveness of different quantitative attributes and their contribution towards final yield was obtained by working out multiple correlation and partial regression (Table 1). This was accomplished by assessing the cumulative effect of yield components on grain yield per plant, taking grain yield per plant as the dependent variable and the other traits as independent variables. The multiple correlation coefficient between yield per plant and other characters was .8425 which means that 71% of the variation in yield per plant can be attributed to four independent variables. The calculated F-value 33.66 (Table 2) reveals that the multiple correlation coefficient is highly significant at the 1% level of probability. The 't' test for significance of the partial regression cofficients indicates that only seeds per spike contributed significantly towards yield per plant while the other three variables (Spike length, spikelets per spike and yield per spike) do not contributed significantly towards yield per plant. This is also confirmed by path coefficient analysis which indicates that the character having the maximum influence on yield per plant is seeds per spike. These results are in accordance with the results obtained by LARIK (1979), SIDDIQUI et al. (1980) and SANDHA et al. (1980). The relative contribution of the basic yield components would be expected to vary considerably depending upon the range in the genetic population and environment (WORLEY et al, 1976). It is therefore advisable to pinpoint the yield components most susceptible to alteration in a particular agricultural environment. From the path coefficient and partial regression analyses carried out in the present work, it may be inferred that seeds per spike is the effective yield component of the wheat cultivar Nayab. References DEWEY, D.R. and K.H. LU 1959. Agron J. 51: 515-518. LARIK, A.S. 1978. Genet. Agr. 32: 237-244. LARIK, A.S. 1979. Wheat Infor. Serv. 50: 36-40. SANDHA, G.S., D.S. PANNU and K.S. GILL 1980. Cereal Res. Comm. 8(2): 401-408. SIDDIQUI, K.A., M.A. RAJPUT and K.H. TAHIR 1980. Genet. Agr. 34: 89-100. STEEL, R.G.D and J.H. TORRIE 1960. Principles and precedures of statistics. McGraw Hill Book Co., Inc. New York pp. 481. WORLEY SMITH, Jr., H. HARMON, Jr. RAMEY, D.C. HARRELL and J.W. CULP 1976. Crop. Sci. 16: 30-34. |
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