118 POULTRY CULTURE 



of union of the two gametes forming the zygote and cell 

 division and formation of a fully developed individual, and 

 third, the separating out of the single structured gametes 

 from the individual or double-structured zygote through its 

 generative gland. 



Nature's scheme of inheritance was first worked out on 

 plants. 



Mendel crossed the tall pea (6 feet in height) on a dwarf pea 

 (1.5 feet high), and, although each kind of plant had been 

 proved to breed true to height, if they were crossed artificially, 

 using either as the pollen parent, the other being used as the 

 ovule parent, the result of crossing tall with dwarf was in every 



T+D 



"YiJO) P Generation 



T 



TjUj JJ Tz Genera-tton 



y , — r— l— 1 1 I — r— ^— 1 1 D F^ Generation 



I T T(D) T(D] D T T(D) T0) D j 

 j" Zl F^Generation 



Fig. 41. — Mendel's illustration of inherited characters: T is for dominant 

 tall.D is for recessive dwarf. 



case nothing but tails. This tall character, because it domi- 

 nated, was called the dominant character. The dwarf charac- 

 ter was called the recessive character. The progeny was the 

 Fi generation (Fig. 41). Seeds from this Fi generation sown 

 the following year gave rise to tails and dwarfs with no inter- 

 mediates. This formed the Fa generation, the tails numbering 

 three to the dwarfs one. From the Fo generation the seeds 

 collected from the dwarf recessive always produced dwarfs. 

 On the other hand, the seeds of the tails, though in physical 

 appearance indistinguishable, some bred tall and some pro- 

 duced both tall and dwarfs in the usual proportion of three 



