Brassinosteroids (BRs) play important roles throughout plant growth and development. Despite the importance of clarifying the mechanism of BR-related growth regulation in cereal crops, BR-related cereal mutants have been identified only in rice (Oryza sativa). We previously found that semidwarf barley (Hordeum vulgare) accessions carrying the "uzu" gene, called "uzu" barley in Japan, are non-responding for brassinolide (BL). We then performed chemical and molecular analyses to clarify the mechanisms of uzu dwarfism using isogenic line pairs of uzu gene. The response of the uzu line to BL was significantly lower than that of its corresponding normal line. Measurement of BRs showed that the uzu line accumulates BRs, similar to known BR-insensitive mutants. The marker synteny of rice and barley chromosomes suggests that the uzu gene may be homologous to rice D61, a rice homolog of Arabidopsis BR-insensitive 1 (BRI1), encoding a BR-receptor protein.A barley homolog of BRI1, HvBRI1, was isolated by using degenerate primers. A comparison of HvBRI1 sequences in uzu and normal barley varieties showed that the uzu phenotype is correlated with a single nucleotide substitution. This substitution results in an amino acid change at a highly conserved residue in the kinase domain of the BR-receptor protein.These results may indicate that uzu dwarfism is caused by the missense mutation in HvBRI1. The uzu gene is being introduced into all hull-less barley cultivars in Japan as an effective dwarf gene for practical use, and this is the first report about an agronomically important mutation related to BRs.Brassinolide (BL) is a firstly identified plant steroid hormone, isolated from rape (Brassica napus) pollen (Grove et al., 1979). Diverse plant species have been found to contain BL and a variety of structural analogs, called brassinosteroids (BRs). With their characteristic physiological effect on plant growth and development, BRs should be included as essential plant hormones, along with GAs, auxins, cytokinins (CKs), abscisic acid (ABA), and ethylene. The effect of BRs on germination, elongation growth, flowering, and sex expressions of plants have been reported, and various application techniques have been tested in the greenhouse and in the field (Yokota, 1999). BR applications have often increased grain and vegetable yields. Plants treated with BRs also acquired resistance to or tolerance against such stresses as cold, drought, salt, disease, and herbicide. In field tests, however, BR effects were unstable and not replicable. The biological activity of these BRs disappeared rapidly due to deactivation and was influenced by environmental conditions (Kamuro and Takatsuto, 1999).In addition to studies on agricultural applications of BRs, BR physiology has also been studied (Yokota, 1997; Altmann, 1999; Bishop and Yokota, 2001). After many BR-deficient and -insensitive mutants were identified in Arabidopsis, BR biosynthesis and signaling have been rapidly clarified. BR biosynthesis mutants such as deetiolated 2 (det2; Chory et...

Cereal Chem. 74(5):576-580The viscoelastic properties and molecular structure of the starch isolated from waxy (amylose-free) hexaploid wheat (WHW) (Triticum aestivum L.) were examined. WHW starch generally had lower gelatinization onset temperature, peak viscosity, and setback than the starch isolated from normal hexaploid wheat (NHW). Differential scanning calorimetry (DSC) showed that WHW starch had higher transition temperatures (T o , T p , and T c ) and enthalpy (∆H) than NHW starch. However, when compared on the basis of amylopectin (AP) content, ∆H of WHW starch was almost statistically identical to that of its parental varieties. Typical Atype X-ray diffraction patterns were observed for the starches of WHW and its parental varieties. Somewhat higher crystallinity was indicated for WHW starch. WHW starch was also characterized by having greater retrogradation resistance. The high-performance size-exclusion chromatography (HPSEC) of amylopectin showed that each amylopectin yielded two fractions after debranching. Although WHW amylopectin had somewhat long B chains, little difference was observed in the ratio of Fr.III/ Fr.II between WHW and its parental varieties.

Cereal Chem. 81(5):666-672The practical applications of flour from waxy (amylose-free) hexaploid wheat (Triticum aestivum L.) were assessed. The applications evaluated were bread, cakes, white salted noodles, and pasta for gyoza. An excessive addition of waxy hexaploid wheat flour to total wheat flour (>20%) resulted in poorer functional properties (sticky, lumpy, or less crispy textures) in almost every end use product. However, incorporation of <20% waxy hexaploid wheat flour, produced considerable improvement in shelf-life characteristics. After one day of storage, the bread from flour including waxy hexaploid wheat flour maintained moistness, softness, and stickiness. This application of waxy hexaploid wheat flour as an antistaling ingredient was also confirmed in cake products. Tests were also conducted on alimentary pasta products. In alimentary pasta, waxy hexaploid wheat flour was most effective when utilized for frozen fried dumplings (gyoza). By using flour including 30 or 50% waxy hexaploid wheat flour, the problem of firmness was solved without other ingredients. In conclusion, flour from waxy hexaploid wheat may be useful in developing more increased staling-and freezing-tolerant grain-based foods. Starch properties could be responsible for these improved characteristics.

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Foxtail millet, common millet and Japanese barnyard millet have traditionally been important food sources in East Asian countries. Although waxy types of foxtail and common millet have been identified, a waxy mutant of the allohexaploid crop Japanese barnyard millet has not yet been reported. However, several Japanese landraces have been identified that have approximately half the level of amylose found in other varieties. We employed one of the low amylose landraces, 'Noge-Hie', to produce waxy Japanese barnyard millet using a c-radiation treatment. The seeds from a single M 2 plant stained red-brown with iodine solution, indicating the starch in the seeds lacked amylose. Colorimetric tests indicated that amylose was not present in endosperm tissue of the mutant, and analysis of starch granule bound proteins showed that waxy (Wx) protein was absent from the starch granules. The waxy trait was stably inherited in subsequent generations. Additionally, a PCR-based analysis demonstrated the presence of three separate waxy genes in the millet, and indicated that the low amylose landraces carry a deletion in one of these three genes.

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Wheat breeding efforts for a half century in Japan were investigated by using of 129 varieties registered in MAFF from 1929 to 1984 in the view point of case history for three years . Varieties released in each breeding station are classified apparently by growth habit associated closely with duration of the cold requirement . Heading date is earlier in varieties released in southwest breeding stations (southern varieties) than in varieties released in northern breeding stations (northern varieties) . Culm length is higher and the pre-harvest sprouting is more sensitive in northern varieties. In quality characters, northern varieties has the higher milling rate, lower apparent amylose content and larger particle size of flour . In varieties released in the Tohoku district, trend of breeding direction with time is smaller ear numbers and larger 1,000-grain weight and greater resistance to powdery mildew . In varieties released in the Kyushu district, a significant correlation with released year was clearly observed with regard to early maturity, short culm length, less grain crude protein content, less apparent amylose content and higher milling rate on breeding advancement .