HETEROSIS IN A NEW POPULATION 



429 



portant, the percentage of lines increasing the yield over the tester parent was 

 much higher among the A lines than among the B lines. 



Table 27.2 shows the performance of A and B lines from Urquiza top- 

 crossed on Leon CrioUo when tested at two different locations. Again the 

 average yield of the A topcrosses was higher than that of the B topcrosses, 

 and the percentage of topcrossed lines yielding more than the tester was 

 higher among the .1 lines than among the B lines. 



The same thing was true in A and B lines obtained from three other varie- 

 ties when topcrossed on Urquiza, as summarized in Table 27.3. These data 

 definitely indicate that the probability of obtaining good general combiners 



TABLE 27.1 



COMPARATIVE YIELDS OF A AND B Si LINES 



OF LEON CRIOLLO IN TOPCROSSES 



WITH URQUIZA AT 3 LOCATIONS* 



* Variety Urquiza was used as check. 



TABLE 27.2 



COMPARATIVE YIELDS OF A AND B Si LINES 



OF URQUIZA IN TOPCROSSES WITH LEON 



CRIOLLO AT TWO LOCATIONS* 



*Leon Criollo was used as check. 



