IBARAKI UNIVERSITY
College of Agriculture, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan.
Nobuyoshi Watanabe.
Italian and Tunisian durum wheats from different eras of breeding were assessed for the presence of a gene for brittle rachis. Nine of 15 Italian durum landraces had brittle rachides. Strampelli's achievement was the release of the well-known variety, Senatore Cappelli, which was derived from a Tunisian landrace, Jenah Rhettifah, which has a brittle rachis. Rachides of two Tunisian landraces were also brittle. Since the 1950s, 16 accessions were released as selections from crosses or mutagenesis involving Senatore Cappelli. Seven of these accessions have brittle rachides. F2 segregation in intercrosses of Senatore Cappelli with other durum accessions with brittle rachides indicated a common allele for brittle rachis. The gene for brittle rachis of Senatore Cappelli was allelic to the brittle allele of the Br-B1 locus on chromosome 3B. Senatore Cappelli was presumably the only source of brittle rachis used in Italian breeding programs. The genes for brittle rachis have been retained in the gene pool of durum wheat, suggesting that the brittle rachis character does is not seem to be associated with an appreciable yield loss in modern farming systems in Mediterranean environments.
Glaucous leaf and tough rachis phenotypes were rare in Ae. tauschii, the D-genome donor to bread wheat. The genes for glaucous leaf and tough rachis were mapped using microsatellite probes in Ae. tauschii. The glaucous phenotype was suppressed by the inhibitor W2I located on chromosome 2DS. The gene W2I was mapped to the distal part of 2DS, and was unlinked to the centromere. This suggests that the distance of the W2I locus from the centromere was maintained during the establishment of hexaploid wheat from its diploid progenitors as the inhibitor gene is at the same position in Ae. tauschii and modern bread wheat. The Brt (Brittle rachis of Ae. tauschii) locus was located on the short arm of chromosome 3D and was linked to the centromeric marker Xgdm72 (19.7 cM). It is noted that Brt causes breakage of the spike at the nodes, thus creating barrel-shaped spikelets, whereas Br1 in hexaploid wheat causes breakage above the junction of the rachilla with the rachis such that a fragment of rachis is attached below each spikelet.
Nobuyoshi Watanabe is now a professor at Ibaraki University since1 December 2005.
NATIONAL AGRICULTURAL RESEARCH CENTER FOR ARGICULTURAL SCIENCES (JCIRAS)
Tsukuba, ibaraki 305-8686, Japan.
Hiro Nakamura.
Introduction. The evaluation method for Japanese hexaploid wheat flour hardness was developed by the Ministry of Agriculture and Forestry (1968) in coöperation with other National Institutes related to wheat. Few studies have been reported on Japanese wheat quality (Nagao 1976, 1977; National Food Research Institute 1984; Takada 1987; Toyokawa 1989a, b). However, the most important characteristic of wheat quality acceptability is wheat flour hardness related to flour yield. There is a little information about the most important quality factors of flour hardness in Japan (Yamashita 1994). However, by the late 1980s, the particle size parameters in wheat flour by laser beam diffractometry method was being used for most flour particle size analyses in the U.S., the AACC technical committee in quality tests for wheat and flour initiated a collaborative study on the determination of wheat flour particle size parameters by the laser beam instrumental method (McDonald 1994). Wu et al. (1990) found that the size distributions of flours measured by sieving and air classification. Devaux et al. (1998) also reported that the detailed particle size distributions can be easily determined by using a laser light apparatus. Flour yield is a main factor affect in wheat bread and noodle quality (Yamashita 1994). Yamazaki and Donelson (1983) reported previously that particle size index for the soft wheat was significantly associated with the break flour yield obtained in milling the common wheat. Particle size in wheat flour is significantly related to the degree of the hardness in the wheat kernel, and hardness is an important factor in flour functionality in wheat food products (Obuchowski and Bushuk 1980). Therefore, it would be of interest to reveal that relationship between flour hardness or flour yield and flour particle size distribution by using laser light diffraction apparatus.
In Japan, a major objective of wheat breeders is to develop new, high flour yielding cultivars with improved bread or Japanese soft noodle-making quality. Wheat for making bread or Japanese soft noodles must have certain minimum standard levels of flour yield and protein content. At the Wheat Breeding Institute, a greater effort is being placed on the improvement of protein quality in the Japanese breeding program (Nakamura 1999, 2000a, b, c). Waxy (amylose-free) wheats have been produced in Japan (Nakamura et al. 1995). Amylose content plays an important role in the quality of wheat since it affects starch properties (Yamamori and Quynh 2000). Therefore, the flour yield of Japanese waxy commercial wheat varieties is greatly important in wheat breeding programs in Japan.
It is well known that as well as being of great importance nutritionally flour hardness plays a fundamental part in food processing, for instance, in the manufacture of bread, biscuits, breakfast cereals, pasta, and Japanese soft-noodle (Udon) products. The aim of this study was to find which flour particle size or flour particle size distribution may be the new flour hardness index instead of glassy kernel ratio (%) in Japan and to find flour particle size distribution most affect flour yield between soft and hard in Japanese wheats.
Flour hardness of breeding or commercial hexaploid wheat from the northern Japan, was related to mean flour particle size and particle size distribution determined by laser diffraction. Hard and soft wheat differed in mean flour particle size and flour particle size distribution patterns from air classification of flour. Hard wheat appeared to differ from soft wheat in mean flour particle size > 64 µm fraction from air classification of flour. Thus, > 64 µm from air classification or screening of flour distinguishes hard wheat, and < 64 µm from air classification or screening of flour distinguishes soft wheat in this study. Hard and soft wheat also were distinctly different in flour particle size distribution patterns from air classification of flour. The two peak particle distribution patterns (pattern II) was shown in soft wheat variety Nebarigoshi, it could be associated to a higher flour yield of soft wheat line. This result suggest that flour particle size distribution pattern II (with two peak patterns) seems to be affected a higher flour yield than that of soft wheat (with only a lower one peak; pattern I) in Japanese wheat.
References.