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

individual lines.
It is generally considered that a minimum goal would be
for semå-dwarfs to exceed the yield level <strong>of</strong> regionally
âdapted tatr c urtír¡ars in trials under average conditions.
Such an íncrease in yield require s a change in the basic
sink <strong>of</strong> the crop and this may initiatly be hard to achieve.
0n the other hand the high tillering seni_dwarf rnay be more
capable <strong>of</strong> providing a larger sink under ¡nore id.eaL growing
conditions. Even lf the sink is not Lncreased the semi_
dwarf stature wour-d be desÍrabre in terms <strong>of</strong> yield stability.
Short stature eontributes strongly to lodging resistance,
and lodging, whether <strong>of</strong> the early or late season type,
frequently is a serious problem. IhÍs ís especÍally the
case in regions where barley is well adapted. and therefore
highest yields are expected. As previously discussed the
semi-dwarf types would likeIy be most suited to and most
useful in these highly productive areas. Development <strong>of</strong>
semi-dwarf lines with high leveLs <strong>of</strong> lodgÍng resistance and
achíeving a yield 1evel conparable to that <strong>of</strong> the better
tal-l genotypes under condÍtj-ons free <strong>of</strong> lodging, would be
a valuable achievement, and should be the initial goal in
any breeding program attempting to develop useful short
statured genotypes.
The results obtained indicate the possibility <strong>of</strong> select-
ing an adapted, short-strawed, barley genotype with acceptable
yield. Several genotypes <strong>of</strong> intermediate and strort helght
showed high yield levels, but they were undesirable due to
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