TY  - GEN
AU  - Nuttonson,M.Y.
TI  - American Institute of Crop Ecology series, study: No. 18 
PY  - 1956///
CY  - Washington
KW  - Agricultural Ecology
KW  - Crop Ecology
KW  - Variability
KW  - Wheat
KW  - Barley
KW  - Rye
ER  -