Effects of reduced plant height on breeding requirements and ...

much as the tall genotypes. Also the F x G interaction at
both sites in L9?5 derronstrated the superior standing
ability <strong>of</strong> the semi-dwarfs under high yieltiing (higher N)
conditions" This was especía1ly noticeable at portage where
lodging was most prominant.
Within the <strong>height</strong> groups there was variable lodging and.
response to N. Bonanza was stronger than C?OZOZI4 and arÂong
the sernl-dwarfs l\{inn64-62 was more lodging resistant than
C703011 a\d. C?O3O3Z. Tn fact C?O3O].L showed a rather high
level <strong>of</strong> loclging at the highest N 1evel at portage, although
not as severe as that <strong>of</strong> the tall genotypes. lhis again
indicates the <strong>plant</strong> helght to lodging association is not
aì.ways constant and it Ís apparent that there are nany
factors besldes <strong>plant</strong> <strong>height</strong> which have a strong infl-uence
on lodglng resistance. In terms <strong>of</strong> breeding methodologyr
therefore, selection pressure for J"odging resistance must
âccompany selection for semi-dwarfism to achíeve the poten_
tial j-n lodging resístance that is possible in this type <strong>of</strong>
material. fhe effects <strong>of</strong> other factors, such as environnent
under which the material ís grown, was evj_denced by the
Sanford and Portage 19?6 locations in the present study.
There, despite better growing conditions and higher yield
levels, no lodging occwred at all, denonstrating the
difficulty encountered when attempting to effectlvely seLect
for lodgíng resj_stance.
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