| Results and Discussion Simple Correlation Coefficient: The estimates of phenotypic correlation coefficients (Table 1) reveal that plant productivity was most strictly affected by seeds/m2 and harvest index followed by spikes/m2. These characters ie. X3, X5 and X2 participated in the variability of yield/m2 from 78 to 89%. This component ranking agrees well with the results reported by LARIK (1979) and SMOCEK (1977). On the contrary association of yield/m2 with days to heading was negative (-.7614). Negative significant association between yield/m2 and days to heading is desirable one, which suggests that early maturing genotypes with higher yield potential may be obtained in the present material. SANDHA et al. (1980) also observed similar association between days to heading and grain yield. Plants/m2 though have contributed to yield/m2 but its contribution is of second order. Path Coefficient Analysis: Path coefficient analysis of different attributes (Table 1) revealed that harvcst index exerted maximum positive direct effect (70.56%) on yield/m2 followed by spikes/m2 (48.33%). On the contrary plants/m2 had the maximum negative influence on yield/m2. However, the major effect of plants/m2 on yield/m2 was through the path of spikes/m2 and harvest index. The negative effect of plants/m2 on yield/m2 may be attributed to interplant competition for nutrients, water, light and limited supply of photosynthates to all the developing sinks created with increased tillers/m2. With the increasing number of tillers/m2 ear potential decreased which consequently affect yield/m2. However, the issue needs further probing before such a relationship could be established. The direct effect of spikes/m2 is 48.33% however, its effect via seeds/m2 and harvest index was substantial. The effect of spikes/m2 on yield/m2 is diminished because of its negative effects through plants/m2 and days to heading. The direct effect of seeds/m2 on yield/m2 is 14.71% the major effects were through harvest index (53.62%) and spikes/m2 (36.14%) whereas its effect via plants/m2 and days to heading is negative. The direct effect of days to heading on yield/m2 is very low (0.30%) but its major effects were through spikes/m2 (-45.20%) and harvest index (-43.68%). Thus it appeared that the most desirable traits for improving yield are harvest index and spikes/m2 followed by seeds/m2. Some attention therefore must be devoted on plants/m2 to improve yielding ability of wheat cultivars under study. |
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