Abstract
Twenty-eight F1 hybrids of wheat and their parents were
grown in field trials at Trumpington,
Cambridge during 1986/87 and 1987/88. They were derived from
crosses between seven ‘modern’
varieties, used as female parents, and either two ‘old’ (Squareheads
Master and Partridge) or two
‘modern’ varieties (Bert and Motto), which were used as
male parents. Grain yield, yield
components, biomass and height were determined. The male parents were chosen
to provide
contrasting phenotypes and genetic backgrounds for the F1 hybrids.
Mid-parent advantage, the
increase of a hybrid for a given character above the mean of its parents,
and heterosis, the increase
of a hybrid above the ‘better’ parent for that character,
were calculated. Most F1 hybrids showed
mid-parent advantage for the characters studied. This tended to be
greatest for hybrids derived from
parents with the largest phenotypic differences in that character.
In contrast, where heterosis occurred
it tended to be greatest where the phenotypic difference between the
parents was least. This suggests
that the beneficial effects of hybridization, resulting from the
dispersion of dominant genes between
the parents, was insufficient to overcome the detrimental effects of
other genes present where the ‘less
good’ parent was substantially lower than the ‘better’
parent. Hybrids derived from the ‘modern’
male parents had greater heterosis for grain yield and mean grain
weight than those from the ‘old’
parents. Of the yield components, positive heterosis for mean
grain weight resulted in heavier seeds
and was the most important yield component in determining heterosis
in grain yield. Heterosis for
the number of grains/ear was small or did not differ
significantly from zero while number of ears/m2
showed negative heterosis resulting in fewer ears/m2 in
the hybrids.
Publisher
Cambridge University Press (CUP)
Subject
Genetics,Agronomy and Crop Science,Animal Science and Zoology
Cited by
7 articles.
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