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

$pikei: pqr llnii Area. The ANOY¡, (fable 16) indica-ted that
inc::easing N significantly increased the nurnber <strong>of</strong> spikes
per unit area as previou.sly reported by several workers
including Konishi (f9?6) and Gardener and RathjerL (I9?Ð"
This increase wâs primaril¡r lirniied to the initial inerement
<strong>of</strong> N, except ai Carroan in Ig?S where the response continued_
throughout al.L N increments and at Sanford in 1pf6 where
there was a sign.if icant response to the finai N increment
(ta¡re r?c ) .
the AtiûVA (îabl_e 16) indicated signåficant d j_fferences
among genotypes for spíkes per unit area existed, and that
no F x G interaction óccut:red.
Further analysis (fable 16) indicated significant
differences between the talls and semi-dwarfs at al-1 sites
in 3-976, This difference was in favour <strong>of</strong> the se¡ní-dwarfs
(ta¡re r?n).
Further single degree <strong>of</strong> freedom comparisons (Iabie l_6)
and the data <strong>of</strong> Table 174 show that most <strong>of</strong> the advantage
<strong>of</strong> the semi-dwarfs came from Mir:lf. 64-62, Õ?o3o3z showed
an advantage over the talls at the lpf6 sites, but semi-
dwarf C703011 was, in fact, lower in spÍkes per unit area
than the ta11s in three <strong>of</strong> the five experinents"
lhe di.sagreement between the analysis <strong>of</strong> Tabl_e 16 and
the lack <strong>of</strong> significant differences ind.icated at Carman,
:..975 in Table 174 arose because the test used in the latter
case was less sensitive tlran the single degree <strong>of</strong> freedom
comparison eraployed Ín îable 16. This si-ngle Cegree <strong>of</strong>
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