70 THE PEANUT— THE UNPREDICTABLE LEGUME 



United States. They are shown here as they could occur if classified by 

 the foregoing system. 



1. Virginia Runner — Prostrate 



2. Jumbo Runner — ' ' 



3. N.C. or Wilmington Runner — " — Virginia 



4. African — ' ' 



5. Virginia Bunch — Erect 



6. Spanish — Erect 



7. Improved Spanish — " — Spanish 



8. Small Spanish — ' ' 



9. Tennessee White — ' ' 



10. Tennessee Red — " — Valencia 



11. Valencia — " 



If this scheme of classification based upon the orders and patterns 

 of branching were generally employed, the understanding of reported 

 experiments, not only in breeding, but in essentially all other types of 

 peanut research would be greatly facilitated. Where original varietal dis- 

 tinctions have been obliterated through crossing and segregation, the 

 parentage and a brief description in the above terms would furnish the 

 needed information. Prevot (54) has already indicated the relationship 

 between branching habit and the problem of fertilizer treatments with 

 peanuts. It is obvious, however, that this relationship could not be the 

 same for both Spanish and Virginia peanuts. 



GENETICS AND BREEDING 



The problem of .the improvement of peanuts through selection is not 

 a simple one. The peanut is a plant which is, in our experience, for all 

 practical purposes 100 percent inbred, difficult to cross, and productive 

 of so few seeds per plant that the recovery of improved types in small se- 

 gregating populations is rendered highly improbable. Consequently to- 

 day's peanut breeder must not only increase the precision of estimating 

 genetic differences within segregating populations, but also must over- 

 come the sterility barriers between the various species of peanuts, gather 

 fundamental biological information on the structure and physiology of the 

 peanut and its relatives, and relate these to the problem of improvement 

 through selection. 



The reproductive behavior {i.e. self-pollination) of peanuts is such 

 that new forms tend to be preserved and isolated from one another. 

 Nevertheless there has been hardly a breeder from the time of Van der 



