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

seni-dwarf wheats to nitrogen fertilizers. All researchers
have reported significant yield increases with increased
nitrogen ínputs up to a certain level, with the improved and
adapted semi-dwarfs yielding more than tal1 cultivars at all
but the lowest nitrogen l-evels. This has especially been
the case under conditions <strong>of</strong> adequate rnoisture, whether by
irrigation or precipitation (Porter g! al., 1964¡ Tuohey,
I9?3), Studies by Beutler arld Foote (L963) and t¡foodward
(L966) gave results índicating a signifícant interaction <strong>of</strong>
genotype and fertílity while Porter et al., (1964), Syme
(f96?), and McNeal et 41. (ry?f), although reporting equal
or greater yields for the semi-dv¡arfs, reported no significant
interaction. Porter et 41. (f964) suggested that the semi-
dwarfs may be more suitable for high production fevels. This
was supported by Syne (L96?).
Gardener and Rathjen (19?5) stated with reference to
barley: "the variatíon in yield response to nitrogen is
remarkable t' and "there is great scope for selecting cultivars
suited to particular nitrogen levels.".
Konishi (I9?6) reported a fertilizer response study
with short-statured barJ-ey and indicated that a fertilj.zer
by genotype interaction occurred. fhe study encompâssed
eight different Japanese dwarf and semi-dwarf strains and
one normal cultivar <strong>of</strong> barley. fhe interaction occurred
because one <strong>of</strong> the short statured genotJ,?e s and the normal
genotype showed a decreased yield at the highest fertílity
Level while the other seven short genotypes showed a yield
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