A brief review on GrainGenes, the database for Triticeae and relatives assembled by the United States Department of Agriculture, was presenterd. The method how to obtain the information of interest was shown. The author also intended to introduce "Mugi-net", a communication tool based on the E-mail system. "Mugi-net" is a mailing list for the researchers working on wheat, barley and relatives. To date, 75 researchers are subscribing "Mugi-net". Additionally, useful URLs on internet were summarized. The URLs are linked by Dr. Eiji Domon and can be connected through the following address; http//infofar,.affrc.go.jp/%7Edomon/mugi-links.htm

T. Terachi (Dept. Biotech., Fac. of Eng., Kyoto Sangyo U.)
Evolution of the mitochondrial genome in Triticeae

In 1984, a multicircular structural model for the plant mitochondrial genome was proposed (Palmer and Shields1984, Lonsdale et al. 1984). Although the model has been widely accepted, it is even unclear whether "a master chromosome" is present or not. Peculiar features of the genome such as "sublimon" and "RNA editing" also make it difficult to study on the evolution of the plant mitochondrial genome. Little is known about mitochondrial genome of Triticeae other than wheat. However, comparative studies on the rrn18/rrn5 repeat between rye and wheat (Coulhart et al. 1990, 1993) showed a possible history of the repeated sequences in grass species. A contradictory nature of the plant mitochondrial genome, represented by the slow rate of base-substitution and the high rate of rearrangement, is emphasized.

G.-Z. Wang¹, N. T. Miyashita¹ & K Tsunewaki² (¹Fac. Agric., Kyoto Univ.; ²Dept. Biosci., Fukui Univ.)
Plasmon analysis of Triticum and Aegilops

To study genetic diversity of organellar genomes of Triticum and Aegilops, 47 alloplasmic lines of the 34 species were analyzed with respect to phenotypic and molecular variations. From the analysis of the phenotypic variations of 22 traits, it was shown that plasmons had a large variation and were calssified into 16 groups. SSCP analysis was conducted to study the molecular variations and the phylogenetic relationship of the genera. A strong evidence that Ae. speltoides is the B genome donor of the common wheat was obtained. In addition, the relationship between the phenotypic traits and the detected molecular variations was investigated.

N. Asakura¹, C. Nakamura¹ & I. Ohtsuka² (¹Kobe Univ., ²Kanagawa Univ.) A nucleus-cytoplasm compatibility gene of T. timopheevi that restors viability and male fertility of an alloplasmic hybrid with Ae. squarrosa cytoplasm

Kihara (1973) was the first to introduce the cytoplasm of Ae. squarrosa into common wheat. Based on the result that Ae. squarrosa cytoplasm causes early maturity and yield increase in some genetic backgrounds, Kihara proposed the nucleus-cytoplasm heterosis (Kihara 1980, 1982). A systematic attempt of introducing Ae. squarrosa cytoplasm into a large number of tetraploid wheat species revealed that 1D chromosome of Ae. squarrosa is required for the NC hybrids to be viable and produce functional pollen (Ohtsuka 1991). It was shown that T. timopheevi and T. araraticum possess a gene or genes functionally similar to that on 1D chromosome. We produced a euploid alloplasmic hybrid of T. durum with Ae. squarrosa cytoplasm by introgressing such nucleus-cytoplasm compatibility (ncc) gene from T. timopheevi. In attempt to tag ncc four RAPD markers were detected that are tightly linked and highly conserved in Timopheevi group of wheat.

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