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Results and Discussion

Analysis of variance has shown that significant difference in yield was observed in data of both the crop season (
Table 1).

Mixture vs Components: Among the component of mixture A of 1979 crop season, wheat variety WL 711 yield significantly higher than mixture A, while HD 2204, WH 147 yielded similar to it. The remaining three components of this mixture i.e. HD 2177, HD 2122 and HD 2009 were inferior in yield. The result of 1980 yield test favoured the superior performance of HD 2122 while the other entries were of as good as the mixture of itself. Among the components of mixture B, none was superior in yield in both years of test. Mixture B was significantly superior in yield over IWP 72 (1979) and WL 410 (1980). Mixture 'C' which consisted of 10 components, yielded significantly inferior than HD 2204, WL 711 and HD 1981 in test of 1979 while in the following year all the components of this mixture except WL 410 were at par to mixture yield.

Mixture vs Multifines: Multiline KML 7406, and KSML 3 showed significantly lower yield than mixture A and mixture B during the test of 1979 while in the following year the yield potential of the multilines and mixtures were similar.

Mixtures vs Component means: The mean yield of mixture were compared with the mean of their respective components by working out t-value. As shown in Table 2; the mean yield of mixture A and mixture B was statistically higher than the mean yield of their respective components during the test of 1979. Yield gain up to 12 per cent was recorded in these mixtures. There was no advantages in mixture C. Mixture B and Mixture C in test of 1980, showed yield superiority as high as 14.2 per cent over component means.

It is evident from this study that mixture yield is not, high than the best adapted genotype. However, yield gain over the component means is observed which is in accordance with the study of Jensen (1965), Gustafson (1953), Frey and Maldonado (1967), Clay and Allard (1969), Shortner and Frey (1979), Shorter (1977), Browning (1957) and Pandey et al (1978). This finding suggests that varietal mixture composed from varieties belonging to particular crop production condition are consistently higher in yield than mixture composed from varieties of different crop production conditions.

Table 3 shows incidence (percentage of plants affected) and intensity of black and brown rusts in respective population of mixtures and their components. It was observed that mixtures had a clear cut advantage in both years of testing over its susceptible components viz WL 711, WH 147, Kalyansona and WL 410. The incidence of black rust in Mixture A was 0-2 per cents with intensity 0-tS as compared to the highly susceptible compoenent WH 147 with incidence of disease 5-10 per cent and intensity 10-20S. Similar comparison with other susceptible components show that disease is checked in mixture. All the mixtures exhibited less disease suscepitbility than their respecitive susceptible components. This trend is distinctly discernible for brown rust as well. Susceptible varieties when mixed in a mixture population the rust build up is very much reduced in comparison to their pure stand. Most of the inoculum that falls on the resistant varieties is further reduced. The reduced rust severity as observed here are similar to those study of Wolfe and Barrett (1977) with powdery mildew of barley and wheat mixture studies of Borlaug and Gibler (1953), Kassem et al (1975) and Barrett (1978).

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