8 MASS. EXPERIMENT STATION BULLETIN 443 



the dams are much less variable in winter clutch size than the daughters are in 

 spring clutch size. While regression was linear, there was no significant correla- 

 tion between mothers and daughters on the basis of 739 degrees of freedom. 

 Summer records were available for 2032 of these daughters, but no correlation 

 was found between daughters' summer clutch size and mothers' winter clutch size, 

 although regression was linear. The number of daughters having a fall record 

 was again reduced over that of the two previous periods. There was no significant 

 correlation between dams' winter clutch and daughters' fall clutch, but regression 

 was linear. 



The table indicates an insignificant correlation between mothers' winter clutch 

 size and daughters' spring, summer, and fall clutch size. These data suggest 

 that selection of breeding females on the basis of their winter clutch size is not a 

 rapid method for improving intensity in other periods of the year. 



Spring Clutch Size of Dams 



Spring clutch records were available on 236 dams. The correlation between 

 the dams' spring clutch and the winter clutch size of 2392 daughters approaches 

 significance, but the regression is not linear. The correlation is so low that it 

 would be of little value from the standpoint of selection. Summer clutch records 

 were obtained for 2021 daughters. Regression of daughters' summer clutch on 

 dams' spring clutch was non-linear, and the correlation was so low that it was 

 insignificant. The data available for 17C0 daughters showed no significant cor- 

 relation between dams' spring clutch size and daughters' fall clutch, although 

 regression was linear. 



Selection of breeding females on the basis of their spring clutch size offers an 

 unsatisfactory method of improving intensity, with the possible exception of 

 winter intensity. 



Summer Clutch Size of Dams 



Summer clutch records are available for 234 mothers. The summer clutch size 

 of these mothers was definitely superior to the winter clutch size exhibited by 

 their 2376 daughters, but variability was greater in the dams. Regression was 

 non-linear and there was little evidence of correlation between mothers and 

 daughters. No significant correlation was observed between mothers' summer 

 intensity and the spring intensity of 2285 daughters, though regression was 

 linear. Regression of daughters' fall clutch size on mothers' summer clutch size 

 was linear, but no significant correlation was found. 



Fall Clutch Size of Dams 



Intensive laying in the fall at the close of the first laying year has been recog- 

 nized as very important from the standpoint of egg production. Its value in 

 selective breeding, therefore, requires study. 



Regression of daughters' winter clutch size on mothers' fall clutch size was not 

 linear and no significant correlation appeared. There was no significant correla- 

 tion between dams' fall clutch size and daughters' spring clutch size, although 

 regression was linear. Regression of daughters' summer clutch size on mothers' 

 fall clutch size was not linear, and there was no significant association. 



In general, the data in Section 2 do not disclose significant correlations between 

 dams' clutch size in the different seasons of the year and the clutch size of their 

 daughters at other seasons of the year. In other words, the selection of dams for 

 large clutch size at one season of the jear gives no assurance that their daughters 

 will exhibit large clutch size at other seasons. 



