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Wheat Information Service
Number 84: 53-55 (1997)
Research information
A simple procedure for the production of
wheat-barley 5H chromosome recombinant lines utilizing 5B nullisomy
and 5H-specific molecular markers
K. Murai1, S. Taketa2, A.K.M.R.
Islam3 and K.W. Shepherd3
1 Research Institute of Agricultural
Resources, Ishikawa Agricultural College, Nonoichi-machi, Ishikawa
921, Japan. E-mail: mural @ ishikawa-c.ac.jp
2 Research Institute for Bioresources,
Okayama University, Kurashiki, Okayama 710, Japan
3 Department of Plant Science, Waite
Campus, University of Adelaide, Glen Osmond, SA 5064, Australia
Barley (Hordeum vulgare L.) is a potential new source of genes
for wheat (Triticum aestivum L.) improvement, e.g., genes
conferring resistance to some diseases and cereal cyst nematode (e.g.
Islam and Shepherd 1992a). The production of 6 of the 7 possible
wheat-barley disomic addition lines by Islam et al. (1981), involving
individual pairs of 'Betzes' barley chromosomes added to 'Chinese
Spring' wheat, has made it possible to manipulate barley chromosomes
in a wheat background.
Wheat-barley disomic addition lines possessing 'New Golden' barley
chromosome 5H added to 'Shinchunaga' wheat was two to three days
earlier in heading time than the original wheat cultivar under
fall-sowing conditions in the field (Koba et al. 1997). Study on
earliness of this line revealed that the 'New Golden' 5H accelerates
narrow-sense earliness and decreases vernalization requirement (Mural
et al. 1997). To introduce the barley genes for early heading on 5H
into wheat, we plan to produce wheat-barley 5H chromosome recombinant
lines. Here, we propose a simple procedure to develop those lines
using 5B nullisomy in combination with molecular markers.
The proposed procedure to isolate recombinants involving 5H and wheat
homoeologues 5A or 5D (5A/D) is shown in Fig.
1. In the first cross, 'Chinese Spring' monosomic 5B is
pollinated with the wheat-barley 5H addition line. Progeny double
monosomic for 5B and 5H (2n=42 and 20"+5B'+5H') are selected and
pollinated with 'Chinese Spring' nullisomic-5B tetrasomic-5A/D in the
second stage of crossing. Among progeny with 42 chromosomes, plants
which are nullisomic-5B trisomic-5A/D monosomic-5H (19"+5A/D'''+5H')
will be identified cytologically (utilizing the C-banding technique)
and with molecular markers. Barley 5H chromosome-specific RAPD
markers developed by Murai (1995) will be used to identify those
plants having 5H. Because of the absence of the Ph1 gene in
the 19"+5A/D'''+5H' stocks, 5H is expected to pair with its
homoeologues 5A/D. Wheat-barley recombinant chromosomes will be
isolated from the selfed progeny of these stocks by using molecular
markers to screen for dissociation of the barley markers. STS-PCR
markers derived from RFLP probes located on 5H (Blake et al. 1996)
will be used to allow efficient screening of recombinants. These
selected plants (2n=42) possessing recombinant chromosome will be
pollinated with nullisomic-5A/D tetrasomic-5B to reintroduce 5B into
the progeny. After selfing the putative recombinants, plants
homozygous for wheat- barley recombinant chromosomes will be
isolated.
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