162 Phjjsiolof/ical Pre -determination 



The question now arises as to whether there is any difference in final 

 yield from immature seeds as compared with that from fully ripe seeds. 

 We have at the outset to distinguish between : 



A. Immature seeds not dried {i.e. sown immediately after harvesting) 

 as compared with fully ripe seeds. 



B. Immature seeds separated from the parent stalk immediately 

 after harvesting and then dried as compared with fully ripe seeds. 



• C. Immature seeds dried on the haulm after harvesting as compared 

 with fully ripe seeds. 



With regard to A no data have been found. In the case of B the 

 question arises as to the effect of storage of the dry seed upon its potenti- 

 ality. The general conclusion to be drawn from the experiments of 

 numerous workers is clearly that immature seeds deteriorate much 

 more rapidly than mature seeds when stored dry under similar con- 

 ditions. For example, Hellriegel(i2), working with rye, found the 

 following percentages of germination after a period of dry storage of 

 seeds harvested at different stages of maturitv : 



And Nobbe(2i), working with red clover, obtained the following 

 results with ripe and unripe seeds respectively after 4 years' {i.e. 1870- 

 1874) dry storage. 



Table V. 



A. Red Clover harvested in 1874 and tested in Doc. 1874. 



B. „ „ 1870 „ „ Dec. 1874. 



100 seeds were used in each experiment. 



Kind of seed used 



A. Fresh seeds \ t, • 



\ Unripe 



B. 4-}'ear-oI(l ( Ripe 



seeds / Unripe 



Percentage of 

 germination 

 after 13 days 



48 



58 



6 



