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Wheat Information Service
Number 93: 9-13 (2001)
Research article
Genetic identification of an amphiploid between
Triticum aestivum and Aegilops variabilis
Yang Zu-jun1, Yang Wu-yun2 ,
Li Guangrong1 and Ren Zheng-long3
1Triticeae Research Institute, Sichuan Agricultural
University, Dujiangyan, Sichuan 611830, China
2 Institute for Crop Breeding and Cultivation, Sichuan
Academy of Agricultural Science. Chengdu, Sichuan 610016, China
3Key Laboratory for Plant Genetics and Breeding, Sichuan
Agricultural University, Yaan, Sichuan 625014, China
Summary
An amphiploid between Triticum aestivum and Aegilops
variabilis was identified by observation of morphology, cytology
and seed storage protein electrophoresis as well as disease
resistance surveys in order to evaluate its potential use for wheat
improvement. Most morphological traits of the amphiploid are
intermediate between its parents, but the plant height of the
amphiploid and its selfed progenies is identical to its
Aegilops parent, with significantly shorter than that of the
wheat parent. It is deduced that the Ae. variabilis parent
would carry a new type of dwarfing gene(s), which is strongly
effective in the wheat background. The complete amphiploid contained
2n=70 chromosomes including eight noticeable satellited chromosomes
and a great reduction of the chromosome number was observed in
amphiploid selfed generation. Giemsa C-banding technique enabled the
identification of Ae. variabilis chromosomes in wheat genetic
background and revealed that the cytological instability of the
amphiploid resulted in the loss of Aegilops and sometime wheat
chromosomes. The most seed storage protein of the amphiploid
overlapped those from the parents and the resistance to powdery
mildew and stripe rust of Ae. variabilis generally expressed
in the amphiploid.
Key words: wheat, Aegilops variabilis, amphiploid,
genetic identification
Introduction
Aegilops variabilis Eig (Triticum peregrinum
Hackel) is an annual allotetraploid species with genome
UvUvSvSv. Genes for,
resistance to root knot nematode (Yu et al. 1990), kernel bunt
(Williams and Mujeeb- Kazi 1996), eyespot (Bang and Hulbergen 1992)
and powdery mildew (Spetsov et al. 1993) from this species were
successfully transferred to common wheat, Triticum aestivum L.
Moreover, Dhaliwal et al. (1993) found that most Ae.
variabilis accessions exhibited high resistance to leaf rust and
stripe rust. To exploit the agronomically desirable genes from
Aegilops, and to investigate their expression in wheat genetic
background, we produced a group of hybrids or amphiploids between
wheat lines and 41 accessions of nine tetraploid Aegilops
species (Yang and Liu in press).
Production of amphiploid is an important step for successful gene
introgression, and the amphiploid also allows reliable evaluation of
genomic interaction between the alien species and wheat (Jiang et al.
1994). To obtain the amphiploid,the crossability of wheat genotype
should be considered. A wheat line J-11 was reported to have high
crossability genes including kr1, kr2, kr3 and
kr4, with alien species (Zheng et al. 1992). Furthermore, Yang
et al. (1998) introduced ph1b gene to J-11
background, named J-11ph1b, which can improve the
effectiveness of J-11 to alien gene transfer. An amphiploid between
J-11ph1b and Ae. variabilis was developed through
colchicine treatment of hybrid F1. In the present paper,
we attempted to identify the J-11ph1b - Ae.
variabilis amphiploid from morphology, cytology, seed storage
protein and disease resistance, in order to evaluate its potential
use to wheat improvement.
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