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Wheat Information
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Number 75: 14 - 20 (1992)
Cytogenetic
study on the origin of some special Chinese landraces of common
wheat
Wu-Yun Yang, Chi Yen and Jun-Liang Yang
Triticeae Research Institute, Sichuan Agricultural University,
Dujiangyan City, 611830 Sichuan, China
Summary
Tibetan Weedrace, Yunnan Hulled Wheat, Sichuan White Wheat complex
(including Chinese Spring) and Xinjiang Rice Wheat are four special
landraces of Triticum aestivum L. which were found in
China. Genomic analysis showed that they were different from T.
aestivum L. var. spelta by one to two pairs of chromosomes. These
four Chinese landraces could be classified into two groups, with the
Xinjiang Rice Wheat in one group and all the remaining in the other.
These two groups were found to be distinguished by two pairs of
chromosomes and one of them was identified as chromosome 6B.
Cytogenetic analysis showed that these two groups of common wheat
landraces might be independently originated in China via pollination
of different accessions of the cultivated wheat tetraploid by the
Aegilops tauschii accessions which has been discovered as a
native species in the northwestern China and as a weed in the central
China as well.
Introduction
The Xinjiang Rice Wheat (XR) is a Polish-wheat-like landrace
collected from Xinjiang. The Tibetan Weedrace (TW) is a
brittle-rachis weedrace in barley field found in Tibet and the nearby
northwestern Sichuan as a weed. The Yunnan Hulled Wheat (YH) is a
glume-hulled landrace growing in Yunnan. The Sichuan White Wheat
complex (SW) are a group of cultivated common wheat with multifloret
spikelets, rounded glume and lemma. All these four special wheat
landraces have been so far only found in China. Morphological and
cytogenetic studies showed that they all had the AABBDD genome (Chen
1980; Lu and Zhang 1983; Yao 1983; Chen et al 1988; Yen et al 1988).
However, these Chinese landraces have some primitive traits that
distinguish them from T. aestivum var spelta (SP) and
the common wheat of the East Mediterranean origin (Yao 1983; Chen et
al 1988; Yen et al 1988). Based on these evidences, they were
considered to be originated in China (Riley et al 1967; Chen 1985;
Chen et al 1988; Yen et al 1988). However, the problems of how and
where they originated still remain unanswered.
In this paper, we describe the results of the cytogenetical analysis
of these four special Chinese common wheat landraces. The origin of
these four landraces are also discussed.
Materials and methods
The plant materials used in this study are listed in
Table1.
They are all maintained in Triticeae Research Institute, Sichuan
Agricultural University.
Interspecific hybrids were obtained by the conventional crossing
method through immature hybrid embryo culture on N6 medium. The
hybrid plants were moved to Barkam, Sichuan in August to survive the
summer and moved back and grown in Triticeae Research Institute of
Sichuan Agricultural University at Dujiangyan City in October.
Mitotic analysis were made in root-tip cells fixed in the 3 : 1
ethanol(95%)-glacial acid solution and stained by the Feulgen
procedure. Meiotic analysis were done in pollen mother cells (PMCs)
fixed and stained as the root-tip cells.
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