| There was highly significant and positive correlation between biological
yield and tiller number. This revealed that increase in tiller number will
increase biological yield vis-a-vis the grain yield. A positive but weak
association of biological yield with plant height, grains per ear, spikelets
per spike and grain weight was also noticed. CHOWDHURY et al. (1988)
observed total biological yield to be the best selection criteria with highest
genetic advance and good heritability. For increasing total dry matter they
had suggested to make efforts for horizontal increase i.e. increase
in tillers per unit area and size of spike and grain. Similar conclusion
can be made from the results obtained during this investigation. The path coefficient analysis using yield as dependent variable and other characters as independent variables was carried out (Table 2). Harvest index showed considerable direct and positive effect in all the three environments. It also had considerable positive effects through biological yield in E2 and E3. High and positive direct effect of harvest index was also reported by SIDHU et al. (1976). Biological yield had a very high positive direct effect on grain yield. Its value was almost equal to its correlation coefficient. Its indirect effects through other traits were unimportant. This indicates that the majority of the variation in grain yield was accounted for by it's association with biological yield. These results are in agreement with earlier study by SIDHU et al. (1976). While concluding it appears that there was a high and consistant positive correlation of grain yield with tiller number, biological yield and harvest index (except in E3) in all the three environments. Path coefficient analysis further revealed that biological yield and harvest index had high positive direct effects on grain yield. Tiller number was another character which had sufficient indirect effect through biological yield. Thus these characters should be given due importance while breeding for higher grain yield. Since, the observations on biological yield and harvest index are difficult to make and also become possible only after harvesting, hence selection may be based on high tillering which may avoid these problems. References CHOWDHRY, R.K., PARODA, R.S. & SINGH, B.P. 1985. Drought resistance in wheat. 1 Grain yield responses and its correlations with grain yield components. Genet. Agra. (in press). DE PACE, C., OTTAVIANO, E. & PACVCCI, G. 1978. Genetic analysis of yield components in durum wheat. Genet. Agrar. 32(1-2) : 125-138. KALTSIKES, P.J. & LEE, J. 1971. Quantitative inheritance in durum wheat. Can. J. Genet. Cytol. 13 : 210-218. SIDHU, G.S., GILL, K.S. & GHAI, B.S. 1976. Correlation and path coefficient analysis in wheat (T. aestivum L.). J. Res. PAU 13(3) : 255-341. |
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