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

A positive rel-atj-onshj-p between coleoptile length and
the ability to ernerge fron greater <strong>plant</strong>ing depth has been
reported in barley ( Kaufmann, 1968) and in wheat (Sunderman,
1963; Burleigh et a]-, L964, Whan, l-926).
A1lan et aI, (L962) reported that another associated
problem was emergence rate. This group and Burleigh et a1.
(f-964) reported that the seni-dwarf short coleoptile wheats
emerged more slowly. fhey calculated an emergence rate
index and found this to be closely related to coloeptile
length.
All"an et al. (1g61) indicated that the heritabilities
<strong>of</strong> <strong>plant</strong> <strong>height</strong> and eoleoptíIe length in wheat are high¡ and
since they are apparently independently inherited, it should
be possible to select for short cuJ-m length with improved.
coleoptile length. This view has been supported by Chowdhry
and A1lan (lgøl).
Boyd gþ a1. (19?r) indicated that seed size and time to
germination were positively related to seedling vÍgor. This
relationship between seed size and emergence characteristics
in barley was previously reported by Kaufmann (1968).
Root System Size in Semi-Dwarfs
Bríggle and Vogel (1968) reported that the earliest
seroi-dwarf wheats did not do we]-l when grown wrder dryland
conditions in the Central United States. They suggested this
was due to problems involving moisture stress, since these
varieties did weLl under irrigation in the same area.
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