Nuttonson 



•131 — 



Phenological Data 



year in any one locality — all provide sources of valuable phenological rec- 

 ords. 



Phenological data when properly organized and analyzed in the light 

 of various latitudinal and climatic factors seem to suggest that mathemati- 

 cally determinable single or several interrelated ecological factors exert a 

 definite influence on the growth behavior pattern of a given variety. 

 Phenological data from a considerable number of various geographic 

 locations are needed in order to be able to analyze and to ascertain the 

 broader implications of these data in regard to certain fundamentals of 

 growth, behavior, and environmental responses of a given variety. The 

 preliminary nature of these phenological studies permits the writer to speak 

 only in terms of some observations of trends of plant behavior rather than 

 in terms of clear-cut conclusions as to the phenological pattern of behavior 

 of various distinct varietal plant material. A demonstration of some of 

 these various trends of phenological behavior of a few selected varieties 

 of plants is all that is attempted at present. 



Table 1 



Phenology of Marquis Wheat at Moro, Oregon* 

 (Time of Seeding Studies During 1926-27 Season) 



• Phenological data upon which this chart and table are based were obtained from B. B. Bayles 

 and J. F. Martin, "Growth Habit and Yield in Wheat As Influenced by Time of Seeding" Journal 

 Agricultural Research, Vol. 42, No. 8, April 15, 1931, pp. 483-500. — Day-degrees were calculated 

 above 32 °F. 



As may be seen from Table 1 and Chart 1 the interval between the dates 

 of emergence and first heading of Marquis wheat provides the least variable 

 mathematical expression when measured in terms of a multiple of the 



