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

<strong>of</strong> different yield components in each, followed by inter_
crossing these to achieve the desired goal <strong>of</strong> high yield <strong>of</strong>
p3.unp barley. fhese second.-stage crosses woul.d nlnimize
some <strong>of</strong> the previously diseussed problems, since all the
måterlal would be short statured.
The barley project at the uni.versity <strong>of</strong> saskatchewan
has, and is following such a procedure (Dr. B.L. llarvey,
personal cornmunication). By selecting against lateness and
sLow, prostrate, early growth but naíntaining good spike
size (in the oríglna1 crosses), selections wíth acceptabLe
levels <strong>of</strong> kernel we lght and number <strong>of</strong> kernels per spike
were obtained. However, a lower number <strong>of</strong> spikes per unÍt
area llníted thetr yielding ability. Short statured geno_
types (siniLar to those used in the present stuäy) with
Large numbers <strong>of</strong> spikes per unit area, good spike size, but
lacking kernel weight were obtained from the Uni"versity <strong>of</strong>
Minnesota program' and hybridized with the saskatchewan
lines. This procedure has ninimized the neeat for selection
for <strong>height</strong> or sp5.ke size (both parents had desirabLe levels)
and now at F, the breeder can coneentrate on selecting to_
Ìvard an optirnum balance between spikes per unít area and
kernel weight, toward the objective <strong>of</strong> maximum yíe1d.
Among the rnaterials in the present study were short-
statured lines whieh embodled. the desired leve1s <strong>of</strong> indiv_
idual eornponents. lhese could. be intercrossed, or crossed
to conplernentary types like those <strong>of</strong> the Saskatchewan pro-
gram, to attain desfred levels <strong>of</strong> all components wíthin
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