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Wheat Information Service
Number 91: 25-29 (2000)
Research article
Genetic variation in allelopathic activity of
wheat (Triticum aestivum L.) genotypes
8. J. H. Rizvi1*, V. Rizvi1, M.
Tahir2, M. H. Rahimian1, P. Shimi1
and A. Atri.1
1Plant Pests and Diseases Research Institute (PPDRI), P.
0. Box 19395-1454, Tehran, Iran
2 International Center for Agricultural Research in Dry
Areas (ICARDA) Regional Office, P. 0. Box 19835-111. Tehran, Iran
Summary
Exploiting genotypic variation of allelopathic activity of crops
for controlling weeds is relatively a younger area of research.
Barley, rice and sorghum are some of the crops which have been proved
promising in this regard. However, there seems to be no report on
genetic variation in allelopathic activity of wheat genotypes, and
its possible application for weed control. Therefore, a suitable
bioassay was developed and various wheat genotypes were evaluated for
their allelopathic activity against Avena ludoviciana. Tested
wheat genotypes showed a significant genetic variation ranging
between +10% to -30%. Varieties like Ghods, Khazar-1 and PI 4512
caused 27.9%, 28.3% and 30.2% reduction, respectively, in dry weight
of the test weed. Interestingly, cultivars Bezostaya-1, Naveed and
Niknejad expressed positive allelopathy, and promoted the dry weight
of Avena by 6.6%,10.9% and 10.4%, respectively. An increase in the
wheat seed density improved the allelopathic inhibition of the test
weed but did not demonstrate any autotoxicity. There was no
correlation between the growth and allelopathic activity of different
wheat varieties. Bezostaya-1, a variety with maximum height (35.1 em)
caused a 6.6% promotion in Avena dry weight. Whereas cv. Inia with a
comparatively lesser height (26.3 em) inhibited the test weed by
28.3%. These results demonstrate that some of the wheat genotypes
carry genes for allelopathic traits (both inhibitory and promoters)
which can be used for breeding wheat varieties with allelopathic
activity for controlling weeds. Genetic analysis of wheat varieties
with significant allelopathic activity and studies on inheritance
pattern of this trait are suggested.
Key words: Triticum aestivum, wheat, allelopathy,
genetic variation, weed control
Introduction
One of the most prevalent interference mechanisms among plants is
competition for the essential factors required for their normal
growth and development. However, in recent times it has been
repeatedly pointed out that release of chemical compounds from living
plants and/or their residues could also be a strong way of
interference. It was Molisch (1937) who coined the term 'allelopathy'
to describe this kind of interference. It denotes that body of
scientific knowledge which concerns any direct or indirect harmful or
beneficial effect by one plant on another (including micro-organism)
through production of chemical compounds (allelochemicals) that
escape in to the environment (Rice 1984).
*Corresponding author: rizvi55@hotmail.com
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