ITEMS FROM JAPAN

GIFU UNIVERSITY

Faculty of Applied Biological Sciences, 1-1 Yanagido, Gifu 501-1193 Japan.

http://www.gifu-u.ac.jp/~watnb/

Nobuyoshi Watanabe.

Reduced height gene in Triticum polonicum IC12196. [p. 77]

Triticum turgidum subsp. polonicum IC12196 is a GA3-insensitive semidwarf accession. To assess allelic relationships, IC12196 was hybridized with the GA3-insensitive cultivar Cando (Rht-B1b), the tall cultivar LD222 (Rht-B1a), and the GA3-sensitive semidwarf durum wheat cultivar Icaro (Rht18). The GA3-response of F2 seedlings from the cross 'Icaro/ IC12196' segregated into the ratio 3 (insensitive): 1 (sensitive). All F2 seedlings from the cross, 'Cando/IC12196' were GA3-insensitive. A single, dominant gene allelic to Rht-B1b on chromosome 4B determines the GA3-insensitivity of IC12196. The allele may be either Rht-B1b itself or one of the alternative alleles at Rht-B1 locus, although further experiments will be required to distinguish between these possibilities. The allele at the Rht-B1 locus of IC12196 was tentatively designated as Rht-B1IC12196. IC12196 may be alternative source of semidwarfing genes at the locus Rht-B1, and it may have potential for the development of durum wheat cultivars.

Chlorophyll b-deficient mutants of Triticum monococcum subsp. monococcum. [p. 77]

The primitive cultivated wheat T. monococcum subsp. monococcum often is viewed as a source of genes to be used in durum and bread wheat breeding programs. In the present study, two chlorophyll-deficient mutants of T. monococcum subsp. monococcum were used to analyze the consequences faced by chlorophyll-deficient mutation. We assessed the inheritance of chlorophyll-deficient mutants purple mutant and Moegi mutant. Both mutations are determined by different single recessive genes. The Moegi mutant is one of the chlorina mutations based on light environmental effect on chlorophyll accumulation. A striking difference was found between the purple mutant and the wild type, which had much higher PSII and Fv/Fm at the given level of absorbed photon irradiance that can be attributed due to the severe reduction of in PSII antenna size in the absence of LHCII.

Chromosomal location of the homoeologous genes effecting phenol color reaction of kernels in durum wheat. [p. 77]

Polyphenol oxidase activity was estimated by the color reaction of kernels to phenol solution. We found that the genes located on homoeologous group-2 chromosomes have an important effect on the level of phenol color reaction of kernels. The genes Tc1 and Tc2 are responsible for high phenol color reaction of kernels and were mapped to the long arms of chromosome 2A and chromosome 2B, respectively. The map distances were estimated to be 46.8 cM for Tc1 and 40.7 cM for Tc2 from the centromere using double-ditelosomics of durum wheat.

Telosomic mapping of chlorina mutant genes on the long arm of homoeologous group-7 chromosomes. [p. 77-78]

Chlorina mutations of hexaploid wheat have somewhat less chlorophyll a and significantly less chlorophyll b than wild-type plants. Ditelosomic lines for long arms of homoeologous group-7 chromosomes of Chinese Spring (CS) and NILs of Novosibirskaya 67 with the chlorina mutant gene were used to map homoeologous chlorina mutant loci (Cn-A1, Cn-B1, and Cn-D1). The distance from the centromere to each of three loci for chlorina mutant genes was mapped at 47.2 cM for Cn-A1 on chromosome 7AL, 42.2 cM for Cn-B1 on chromosome 7BL, and 42.0 cM for Cn-D1 on chromosome 7DL. The newly developed CS ditelosomic 7DL line was useful to analyze the genes on chromosome 7D.

Publications. [p. 78]

• Goncharov NP and Watanabe N. 2005. Physical mapping and chromosomal location of photoperiod response gene Ppd2 in common wheat. Breed Sci 55:In press.
• Kubaláková M, Kovárová P, Suchánková P, Cíhalíková J, Bartoa J, Lucretti S, Watanabe N, Kianian SF, and Dolezel J. 2005. Chromosome sorting in tetraploid wheat and its potential for genome analysis. Genetics (In press).
• Kubo K, Jitsuyama Y, Iwama K, Hasegawa T, and Watanabe N. 2004. Genotypic difference in root penetration ability by durum wheat (Triticum turgidum L. var. durum) evaluated by a pot with paraffin-Vaseline discs. Plant and Soil 262:169-177.
• Kubo K, Jitsuyama Y, Iwama K, Watanabe N, Yanagisawa A, Elouafi I, and Nachit MM. 2005. The reduced height genes do not affect the root penetration ability in wheat. Euphytica 141(1-2):105-111.
• Watanabe N. 2004. Chlorophyll a fluorescence yield and inheritance in two chlorophyll b-deficient mutants of Triticum monococcum. Cereal Res Commun 32:187-192.
• Watanabe N, Takeuchi A, and Nakayama A. 2004. The inheritance and chromosomal location of the genes for phenol colour reaction of grain in durum wheat. Euphytica 139:87-93.
• Watanabe N. 2004. Triticum polonicum IC12196: a possible alternative source of GA3-insensitive semi-dwarfism. Cereal Res Commun 32:429-434.
• Watanabe N. 2005. The occurrence and inheritance of a brittle rachis phenotype in Italian durum wheat cultivars. Euphytica 142(3):247-251.
• Watanabe N, Imamura I, and Koval SF. 2005. Mapping of chlorina mutant genes on the long arm of homoeologous group 7 chromosomes in common wheat ditelocentric lines. J Genet Breed 58:In press.
• Watanabe N, Nakayama A, and Ban T. 2005. Cytological and microsatellite mapping of the gene for liguleless phenotype in durum wheat. Euphytica 140(3):163-170.

NATIONAL AGRICULTURAL RESEARCH CENTER FOR ARGICULTURAL SCIENCES (JCIRAS)

Tsukuba, ibaraki 305-8686, Japan.

Hiro Nakamura.

Effect of sensory viscoelasticity texture on Japanese udon noodle-making quality. [p. 78-80]

Japanese soft noodle (udon) wheat cultivars and lines have different texture characteristics, flour protein contents, and flour amylose contents for cooked udon. Udon-making quality fingerprints were used to determine flour protein content, flour amylose content, flour breakdown scores on the Buhler viscograph test, and sensory viscoelasticity texture scores on cooked udon in this study aimed at improving Japanese udon-making quality. We have speculated on the relationship between flour protein content (%), flour amylose content (%), peak viscosity or breakdown on viscograph tests, sensory tests on cooked noodles (eating-quality of the noodles), and good udon-making quality.

Japanese consumers consider cooked udon texture to be an important quality attribute, and many Japanese consumers prefer cooked udon that has the good viscoelasticity, surface firmness, surface smoothness, and taste of the cultivar Tihokukomugi. Evaluation methods for Japanese udon wheat quality assessment were developed by the Ministry of Agriculture and Forestry in 1985 in coöperation with other National Institutes related to wheat. Few studies have been reported on Japanese wheat quality, however, the most important characteristic of wheat quality acceptability are udon sensory tests related to udon-making quality. Little information is available about the most important quality factors of udon-making quality in Japan. By the late 1980s, amylose content in wheat flour was being used for useful analyses in Australia. Low amylose content of flour is correlated with good udon-making quality. In Japan, a major objective of wheat breeders is to develop new, high flour yielding cultivars with improved udon noodle-making quality. At the Wheat Breeding Institute, a greater effort is being placed on the improvement of udon quality in the Japanese breeding program, and Japanese hexaploid wheats are unique in terms of new types of N-terminal amino-acid sequences.

Many types of noodles are produced throughout the world. Udon is a type of noodle prepared from a dough containing wheat flour, water, and salt. The standard of identity for noodles in Japanese specifies that they usually are made from hexaploid, not durum, wheat. Udon is the most popular noodle in Japan. The major components of starch are amylose and amylopectin, and the amylose content is a main factor affecting wheat udon noodle quality. Amylose content of wheat contributes to starch pasting and gelatinization properties. The eating quality of Japanese udon noodles was negatively correlated with starch amylose content and positively correlated to starch amylopectin content. Our objective was to develop an instrumental method of determining good udon-making quality after cooking.

To determine the effect not only of flour amylose content but also flour protein content on udon quality, the low amylose (flour amylose content ranging from 22.2 to 23.1 %) line Tohoku 206 (named Nebarigoshi for new cultivar registration) with good udon-making quality; the commercial cultivars Koyukikomugi, Kitakamikomugi, Nanbukomugi, Akitatuko, Shiranekomugi, Shunyo, and controls; the ASW (good udon quality) wheat Norin 61 (a standard-quality for sensory evaluation tests on cooked noodles); and Tihokukomugi (good udon quality) were chosen for udon-making quality evaluation. Japanese udon was developed over many years using domestic wheat, and such products have long been accepted by the Japanese. However, ASW is a wheat class mainly and desirably used for the production of udon in Japan at present. ASW is reported to be superior to Western White (WW) wheat in udon quality. Japan has continuously imported udon wheat as ASW wheat from Australia for many years to produce flours for udon-noodle products. Procedures are needed to test the improved udon-quality wheats to meet the demands of targeted noodle markets.

Correlation analysis provides a useful assessment of udon-quality lines and commercial cultivars for quality evaluations (Table 1). Result also showed that flour protein content was significantly correlated with the sensory viscoelasticity scores on cooked noodles (r = -0.3913, P < 0.05), udon surface firmness on cooked noodles (r = -0.5128, P < 0.01), total sensory eating-quality score on cooked noodles (r = -0.4211, P < 0.05), and peak viscosity on viscograph (r = -0.5600, P < 0.01). Flour amylose content was significantly correlated with the sensory viscoelasticity score on cooked noodles (r = -0.7123, P < 0.01) and breakdown on viscograph (r = -0.8732, P < 0.01). The relationship between sensory viscoelasticity scores on cooked noodles and total sensory eating-quality score on cooked noodles was important to this study. The highest correlation coefficient was r = 0.9927, P < 0.01 and revealed that good udon-making quality index can be determined by the sensory viscoelasticity scores on cooked noodle in general. The correlation between the sensory viscoelasticity scores on cooked noodle and total eating-quality scores (r = 0.9927, P < 0.01), sensory taste scores on cooked noodles (r = 0.7325, P < 0.01), breakdown (r = 0.7877, P < 0.01), and amylose content (r = 0.7123, P < 0.01) also were relatively high and significant.

Because the correlation between the sensory viscoelasticity score on cooked noodle and total eating-quality score strongly related to good udon-making quality (r = 0.9927, P < 0.01), good udon-making quality can be determined by measuring the sensory viscoelasticity scores on cooked noodles. Protein content is not correlated with surface firmness on cooked noodle. Glutenin:gliadin ratios also vary considerably within and among soft wheat cultivars, supporting a relationship between protein composition and end-use potential. On the other hand, Japanese udon-quality wheats also induced qualitative differences between the composition of 53-kDa endosperm protein band and the HMW-glutenin subunit 2*. The 53-kDa protein band played an important role in good sensory viscoelasticity scores on cooked noodles related to most important udon eating quality in Japanese wheats. Protein content was correlated with surface firmness, viscoelasticity, total eating-quality scores on cooked noodles, and peak viscosity in this study. The protein content of udon has been shown to significantly influence the cooking quality of udon. Not only flour starch-amylose content but also flour protein content strongly effects udon product characteristics made from soft-grained wheat. In fact, protein content also may be an important contributor to udon-wheat functionality and product quality. Protein content of pasta influences pasta-making quality, similar to that of udon-making quality in this study. Udon wheats have noodle-quality factors and end-uses very different from those of hard wheats, and udon wheats have been bred with lower protein content than that of hard bread wheat.

Correlation analysis also has provided a useful assessment of Japanese udon-noodle lines and commercial cultivars for good udon-making quality. Results also revealed that the sensory taste score on cooked noodles was significantly correlated with the sensory viscoelasticity score on cooked noodles (r = 0.7325, P < 0.01), surface-firmness (r = 0.6002, P < 0.01), and surface-smoothness on cooked noodles (r = 0.8302, P < 0.01). The total eating-quality score on cooked noodles was significantly correlated with sensory viscoelasticity score on cooked noodle (r = 0.9927, P < 0.01), sensory surface-firmness on cooked noodles (r = 0.8501, P < 0.01), and the sensory-smoothness on cooked noodles (r = 0.9327, P < 0.01) also were relatively high and significant. Quality characteristics that contribute to the production of improved udon noodles include the sensory viscoelasticity score on cooked noodles, high starch peak viscosity, high breakdown score on viscograph, low flour amylose content (high amylopectin content), and reasonable flour protein content. The Australian commercial cultivar Rosella is a soft-grained wheat with high pasting properties that is used in the production of Japanese udon noodles. The landrace AUS 4635 has a high starch pasting peak viscosity, high breakdown, low amylose content, low protein content, soft grain texture, and high protein quality flour. This wheat is an ideal parent to use in a breeding program that aims to increase the genetic variation available for developing new wheats with good udon-quality characteristics. The genetic diversity of wheat breeding program is relatively narrow when compared with the genetic resources available.

The quality of the cooked udon noodle is judged by sensory viscoelasticity scores on cooked noodles. These sensory viscoelasticity scores on cooked noodles (eating quality) contribute mainly to the total eating-quality scores related to good udon-making quality in Japan. The sensory viscoelasticity scores could be most important Japanese soft udon-quality evaluation index. The present study developed and/or evaluated wheat cultivars with high-quality Udon characteristics for Japanese breeding programs. Further work using a greater number of pure cultivars or lines with different genetic backgrounds, however, is needed to confirm these results in this study.

Acknowledgment. The author gratefully acknowledges the staffs of field section and wheat breeding laboratory at Tohoku National Agricultural Experiment Station for helping with the analyses and crops production.