In Tokachi and Abashiri distidets in eastern Hokkaido, Japan, the minimum temperature often drops to below 10°C and rain in common during the harvest month of August. As a consequence, the development of varieties that are tolerable to sprouting under low temperature and water absorption condition is necessary. The most tolerant spring semi-dwarf line, OS21-5, to germination at 10°C was selected under low temperature conditions from the first cross of Tordo (Rht3)/Zenkouji-komugi in 1982. It was widely used as gene source for breeding of pre-harvest sprouting resistance and year after year OS21-5 has contributed to produce transgressive lines as follows; spring wheats OS38 and OS39, selected from 8019R1/ OS21-5//OS21-5, winter wheats OW77 from OS21-5/ Lancer, OW104 from OS21-5/61199, OW93 from KK1551/OS21-5//W140-37/KK1646, and OW97,98 and 99 from OW63/KK1647. Recent some winter wheat lines have been well improved on the agronomic characteristics except flour quality.

S-1-4 K. Takata (National Agric Res Center for Hokkaido Region)
Breeding for bread-making quality of winter wheat

More than decade has passed since the beginning of our breeding program for bread-making quality. Relationship between high molecular weight glutenin (HMWG) subunits and bread-making quality was studied for first step. HMWG subunits 5+10 coded by Glu-D1 showed much larger effect on the physical properties of dough than subunits 2+12, 4+12 and 2.2+12. Subunit 20 was the weakest physical property of dough at the Glu-B1 allele. Both subunit 20 and subunits 2.2+12 showed extremely poor functional properties. We have introduced subunits 5+10 to improve bread-making -quality at first step. Now we are pursuing balance of strength and extensibility of dough for next step. Canada Western Extra-Strong Red Spring wheat, which has extremely strong dough properties, shows unique properties. For the improvement of flour quality in Japanese wheat, it would be useful to detect the protein components related to the unique properties and introduce them into Japanese wheat cultivars. We have noticed extra strong properties of Hard Red Winter wheat line KS 831957 and have tried to introduce its properties into Japanese wheat. It is considered that combination of a specific low molecular weight glutenin (LMWG) and HMWG subunits 5+10 give extra strong property. Bread-making quality is a complex character consists of HMWG, LMWG, gliadin, lipids, pentosan and starch. We have to elucidate each key factor and it will be very helpful tool for the breeding of bread- making quality.

Abstracts of the second symposium

S-2-1 N. Sakurai (Kazusa DNA Research Institute)
Current macroarray analysis and its extent of utilization - implications from a study of Arabidopsis tetraploids.

We have prepared macroarrays which carry 13,536 clones of non-redundant ESTs from Arabidopsis, and have utilized them to profile gene expression in various states of tissues. By improving the spotting procedure, hybridization and detection methods, and introducing statistical processing for data analysis, we can now obtain expression data for each gene with annotations on the data reliability. Nonetheless, some problems remain to be resolved. A case is when we compare two individuals or tissues that are in different developing stages. As long as we apply mean, median, or other measures of central tendency for normalization of signal intensity, there is a postulate that most of genes are unchanged, or sum of all variance is constant between the both. In our laboratory, diploid and tetraploid Arabidopsis were applied to macroarray analysis as a model system to depict a difference between both nuclear phases. Some genes were significantly extracted as a feature of tetraploids. However, this is rather skeptical interpretation, because there is no certification that the total abundance of mRNAs is the same in diploid and tetraploid plants, even if they were grown under a same condition. How we can overcome this problem? Over discussing such topics, I'd like to introduce the utilization and application of array technology.

S-2-2 Y. Ogihara (Kihara Inst Biol Res & Grad Sch Integrated Sci, Yokohama City Univ)
Toward development of functional genomics in wheat

Recent developments of functional genomics in model plants such as Arabidopsis and rice, enable us to investigate overall gene constituent and expression patterns. In wheat, earnest research works such as mapping of DNA markers, especially Bin mapping of sequenced cDNA clones, and large scale analysis of ESTs in various tissues during wheat life cycle, can offer the tools for functional genomics. Recently, we have developed some of such basic tools for functional genomics: these are a large body of EST data base, cDNA microarray including microarray spotted full length cDNAs, and SNPs analysis of hexaploid wheat. These tools for functional genomics are now available to wheat researchers. Furthermore, we have a plan to set up data base for comparative and functional genomics in wheat.