PREVIOUS EXPEEIMENTS WITH FIRST-GENEEATION HYBRIDS. 15 



The table further shows the marked decrease in size of ear in the 

 hybrids that follows even one generation of self-fertilization. There 

 is, however, so much ''splitting" in the type of the ears in the second 

 year that their size, as compared with those of the second generation, 

 can not fairly be expressed in averages. 



The following year, 1892, Morrow and Gardner, also at the Illinois 

 station, reported the results of tests of five first-generation hybrids 

 compared with their parent varieties." In all cases the yield of the 

 cross was greater than an average of the parents and in three cases it 

 exceeded that of either parent. Stated in bushels, the increases 

 above the average of the parents ranged from 1.2 bushels, or 1.9 per 

 cent, to 17.2 bushels, or 28 per cent, the average increase being 13.8 

 per cent. The average increase of the crosses over the highest yield- 

 ing parents was 4.66 bushels per acre, or 6.5 + per cent. The com- 

 parisons were apparently made in jL.acre plats. The results of the 

 experiment are shown in Table II. 



Table II.— Results of experiments by Morrow and Gardner xviih corn hybrids at the Illinois 

 Agricultural Experiment Station in 1892. 



Variety. 



Burr's White 



Cranberry 



Average 



Cross 



Burr's White 



Helm's Improved 



Average 



Cross 



Learning 



Golden Beauty 



Average 



Cross 



Champion White Pearl 

 Leaming 



Average 



Cross 



Burr's White 



Edmonds 



Average 



Cross 



Yield per acre. 



Number 

 of ears. 



9.960 

 9,200 



9,580 

 7,080 



9,960 

 10,880 



Air-dry 

 corn. 



Bushels. 

 64.2 

 61.6 



62.9 

 64.1 



64.2 

 79.2 



10, 420 

 11,000 



10.440 



8,280 



9,360 

 11,520 



11,080 

 10,440 



10, 760 

 8,760 



9,960 

 9,040 



9.500 

 10,400 



71.7 

 73.1 



73.6 

 65.1 



69.3 

 86.2 



60.6 

 73.6 



67.1 

 76.2 



64.2 

 58.4 



61.3 

 78.5 



It will be noted that the crosses in this experiment were all between 

 good-yielding varieties and apparently under favorable conditions. 

 The relatively uniform results also indicate a small experimental error. 



a Morrow, G. E., and Gardner, F. D. Field Experiments with Com, 1892. Bulletin 

 25, Illinois Agricultural Experiment Station, 1893, pp. 179-180. 

 52927°— Bull. 191—10 3 



