Division of Botany, I.A.R.I., New Delhi
One hundred varieties of linseed were grown in a randomised block design in 1958–59 rabi, to study the association between yield and some yield contributing characters and between the different yield components, when (a) all the hundred varieties were considered together and (b) when they were grouped into four classes based on seed size and colour. Total correlations were calculated at error, varietal and genetic levels and partial correlations at error and varietal levels.
The correlation coefficient obtained between yield and some of the yield contributing characters showed that in three out of twelve correlations significant differences were present in the estimates of ‘ r ‘ from the different groups. When the association between yield and 1000-seed weight was considered, at the genetic level the ‘ r ‘ values were high in three of the four groups as well as when all the hundred varieties were considered together. The association between yield and capsule number also showed that the estimates of ‘ r ‘ from the different groups were heterogeneous both at the error and genetic levels.
In the correlation between the yield components considered here, the estimates of ‘ r ‘ obtained from different groups showed significant differences in eight out of eighteen correlations. When the association between 1000-seed weight and capsule number was considered at genetic level there was evidence for the heterogeneity of the estimates of ‘ r ‘ from the different groups. In the association between 1000-seed weight and ripening period, the estimate of ‘ r ‘ from the yellow small group differed from all the others in being non-significant at the error level. At the genetic level, however, the yellow bold group deviated from the rest. Similar heterogeneity between different estimates of ‘ r ‘ calculated from different groups was met with at the genetic level between capsule number and number of seeds per capsule; at varietal and genetic levels between 1000-seed weight and number of seeds per capsule and between ripening period and number of seeds per capsule.
In the case of partial correlations also there was evidence of heterogeneity of the estimates ‘ r ‘ obtained from the different groups.
The above findings would seem to lend support to the hypothesis that the existence of a particular type of association between any two characters in a particular group of varieties need not necessarily mean that the same type of association will be present if another group of varieties is considered.
