110 BREEDING CROP PLANTS 



Time of culm formation was carefully studied by Hoshino 

 (1915), who crossed an early with a late variety. The parents 

 averaged 83.8 and 113.2 days, respectively, from time of planting 

 to jointing, the parental average being 98.5 days, while the FI 

 gave an average of 94 days from planting to jointing. The F% 

 generation equalled the combined range of the parents. Some 

 forms bred true to the parental types in F 3 . One form which 

 segregated in F 3 was much less variable than the F 2 . This line 

 could be explained by the presence of a single heterozygous factor 

 for time of shooting. The author suggests that three multiple 

 factors will explain the results. 



Kock (1917) crossed Karang Serang, an early maturing good 

 quality rice, with Skrivimankotti, a variety of high yielding 

 ability. Results were not easily explained on a factor basis. 

 After seven years some hybrids showed considerable uniformity. 

 Improvements in quality and quantity of yield were obtained as 

 shown by a comparison of the parents and the better of these 

 hybrid lines. 



These facts show that correct methods of breeding rice are 

 similar to those of the other small grains. 



