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

Their results were from a barley trial, but si¡nilar reactions
have been reported with the other cereals (Porter g-!. ê.!. '
1964).
Frey et aI. (1951) concluded, n'in general' crops in
which one variety has a small area <strong>of</strong> adaptation (such as
corn) tend to show a significant variety by fertility level
interaction, while those crops in which any one variety has
a large area <strong>of</strong> production ( such as oats) do not show
signíficant variety by fertitity level interactions.I' wheat
and barley would be in this latter category. At the time <strong>of</strong>
this stateroent not nearly as much breeding work had been
done in wheat and barley, there were not as large a number
<strong>of</strong> varieties as there are at present, and the semi-dwarfs
had not yet become irnportant or avaílable.
The introduction and use <strong>of</strong> seni-dwarf genotypes has
l.ed to a renewal <strong>of</strong> interest in the ability <strong>of</strong> Índivídual
genotypes to respond to increased leve1s <strong>of</strong> nitrogen
fertility. As already mentioned Briggle and Vogel (1968)
and Chandle? (1969) have indicated that their short stã.tured
wheat and rice cultivars do respond better to higher rates
<strong>of</strong> nitrogen than otder standard <strong>height</strong> types, primarily due
to lodging resistanee. However, Briggle and Vogel (f968)
indicated there was also some inherent yield advantage, and
Beech and Norman, (1968) indicated that the semi-dwarf
wheats showed a greater yÍeld response to applíed nitrogen
in their studies ín Àustralia.
Other workers have investigated the response <strong>of</strong> the
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