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

parameters Ínvestigated. the very high herítability <strong>of</strong>
<strong>plant</strong> heíght suggested that the selection <strong>of</strong> short statured
genotypes should present no probJ.ems. On the other hand.,
the overall breeding proeedure may have to be somewhat
altered to attain the usual performance objectives in
populations ínvolving short-statured genotypes. Á,rnong the
reasons for this are: the smal1 proportion <strong>of</strong> short tJrpes
derived from some crossesi the 1ow competitive ability <strong>of</strong>
semi-dwarfs relative to the tall segregates¡ and the large
number <strong>of</strong> undesirable character associatíons with <strong>reduced</strong>.
<strong>plant</strong> <strong>height</strong>.
Uithin the scope <strong>of</strong> the sample investigated, which was
small by <strong>plant</strong> breederrs standards, the idear conbination <strong>of</strong>
short <strong>height</strong> and adequate levels <strong>of</strong> other important agronomic
parameters was not found. However, consÍdering the total
number <strong>of</strong> short strawed l"lne s ineluded in the study, the
results were erlcouraglng.
The snall proportion <strong>of</strong> seml_-dwarf types may have re_
sulted fron the adverse conditions ( salínity) encountered
during the F4 increase Ín Californía. Several lines whieh
were increased either were not returned or produced insufficient
seed to be included in the study. îhis salinity
may have particularly affected the semi-dwarfs, due to their
inability to perform well under stress cond.itions, as was
denonstrated throughout the study.
Although the <strong>height</strong> di.fference bstv{een the tal1 and the
semi-dwarf in barley is generalLy assumed. to be simply
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