Barley yellow mosaic virus (BaYMV), which is transmitted by the soil-borne fungus Polymyxa graminis, causes serious damage on winter barleys in East Asia and Europe. Resistance loci were identified on two recombinant inbred populations derived from Russia 6 x H.E.S. 4 (RI1) and Harbin 2-row x Turkey 6 (RI2), and a doubled haploid (DH) population derived from Haruna Nijo x H602 (Hordeum vulgare ssp. spontaneum). By the reaction to BaYMV on field in 2003 season, four, five and three QTLs were detected in the RI1, R12 and DH populations, respectively. The relationship between the QTLs identified in this study and the reported BaYMV resistance genes, described as rym1 to rym13 is discussed.

P-13 H. Nishida, Y. Ohmura, Y. Akashi, H. Yoshino, K. Kato (Faculty of Agriculture, Okayama University)
Geographical variation in the promotor sequence of a Vrn-A1 allele in hexaploid wheat

In hexaploid wheat, a Vrn-A1 allele for spring growth habit has three variations in its promotor region; 20 bp deletion, no in/del (the same as winter allele), and 124 bp insertion, among which the last variation has not been found in tetraploid wheat (Yan et al. 2004). We investigated these variations among 200 wheat landraces, with the Vrn-A1 allele, collected from various parts of the world. Geographical distribution of each variation suggested the transmission routes as below. The no-in/del type transmitted eastward along the southern foot of the Tibetan highland to the northern part of China and southward to the northeastern part of Africa, the 20 bp-deletion type transmitted to the north-eastern part of Africa and the Mediterranean region, and the 124 bp-insertion type transmitted to the northern part of China along the Silk road and to the Mediterranean region and Europe.

P-14 S.K. Ghimire¹, T. Ikeda², N. Ishikawa², S. Ohnishi¹, Y. Akashi¹, H. Nishida¹, K. Kato¹ (¹Faculty of Agriculture, Okayama University, ²WeNAJC)
PCR-based evaluation of genetic diversity in HMW- and LMW-glutenin subunit in wheat

Genetic diversity in high molecular weight (HMW-GS) and low molecular weight glutenin subunit (LMW-GS) was analyzed by PCR-based technique. Among 634 wheat accessions examined, three, five and six alleles were identified at Glu-A1-1 , Glu-B1-1 and Glu-D1-1 locus,respectively. Glu-A1-1a, Glu-A1-lb and Glu-A1-1c were frequently observed in South and East Asia, Europe and Central Asia, respectively. Among the alleles of Glu-B1-1, Glu-B1-1a was frequent in all areas analyzed, while Glu-B1-1d was frequent in England and France. New allele at GluD1-1 locus was mainly found in West Asia. Glu-1D-1e was frequently observed in Japanese accessions, and also in two and one accessions from Afghanistan and Korea, respectively. We amplified type VI genes of Glu-A3 and type II genes of Glu-B3 for LMW-GS after Ikeda et al. (2002), and five and three bands with different size were observed, respectively. 1240 bp type was frequently found in Europe, and its frequency decreased in East Asia where 1320 bp type was frequent. Similar geographical cline was observed also in Glu-A3. PCR products with different size were sequenced for both Glu-A3 and Glu-B3, and compared with the known sequences.

P-15 H. Tanaka, R. Shimizu, H. Tsujimoto (Faculty of Agriculture, Tottori University)
Contribution of low-molecular-weight glutenin subunits to dough strength in common wheat (Triticum aestivum L.)

To analyze the effect of low-molecular-weight glutenin subunit (LMW-GS) genes on dough strength, /?locus-specific primers of LMW-GS genes and gliadin bands tightly linked to LMW-GS genes were used in common wheat. Segregation analysis of the F₂ progeny from a cross between Haruhikari, a good bread-making quality cultivar, and Asakaze-komugi, a poor bread-making quality cultivar, showed that the significant effect on dough strength was concerned with one amplified LMW-GS gene located on Glu-B3 locus from Haruhikari. The LMW-GS gene of Haruhikari relative to Asakaze-komugi had a seven amino-acid deletion in the repetitive domain, and three amino-acid substitutions caused changes of hydrophilicity. The presence of the LMW-GS gene and other LMW-GS genes tightly linked to it may affect the dough strength.