TY  - JA
AU  - Pluckneet,D.L.
AU  - Smith,N.J.H.
TI  - Sustaining agricultural yields:  as productivity rises, maintenance research in needed to uphold the gains
SN  - 0006-3568
U1  - 86-071687 
PY  - 1986///
KW  - America
KW  - Breeding
KW  - AGROVOC
KW  - North America
KW  - Policies
KW  - Production
KW  - Selection criteria
KW  - Plant breeding
N1  - ill. references
T2  - BioScience American Institute of Biological Sciences
ER  -