Japanese Wheat Cultivars Research Articles

Photoperiod-sensitive Cytoplasmic Male Sterility Induced in Japanese Wheat Cultivars by Transferring Aegilops crassa Cytoplasm.

Triticum aestivum cv. Norin 26 with Aegilops crassa cytoplasm shows photoperiodsensitive cytoplasmic male sterility (PCMS): The alloplasmic line is almost completely male sterile under longday conditions (≥l5 h light period), but highly male fertile under shortday conditions (≤14.5 h). To examine the effects of the Ae. crassa cytoplasm on other wheat cultivars, this cytoplasm was introduced into 17 Japanese wheat cultivars by repeated backcrosses. Among their alloplasmic lines which reached B5 (11 lines) or B4 (six lines) generation, those of nine cultivars showed PCMS caused by the Ae. crassa cytoplasm, while those of other eight cultivars did not. Thus, the former nine cultivars are converted to the PCMS Iines by transfer of the Ae. crassa cytoplasm, and the latter eight cultivars have demonstrated to carry fertilityrestoring (Rf) gene(s) against PCMS. Pedigrees of the Japanese wheat cultivars suggest monophyletic origin of the Rf gene(s).

Elongation and Branching of Seminal and Nodal Roots in Wheat Grown under Field Condition.

Growth and development of seminal and nodal roots in wheat were examined. After the experimental site was plowed and fertilized, a Japanese wheat cultivar was planted. Root system distributed in the top 30 cm of soil was taken using the monolith method every 2 weeks throughout the growing season. In each sampling, all seminal and nodal roots of three selected plants with normal size were identified and the number of root axes were recorded. Then the length of the root axes and the total root length including all lateral roots were measured, and the branching degree was examined as well. The total number and length of root axes in the seminal roots increased and almost reached a constant value soon after planting. The total root length of seminal roots, on the other hand, increased thereafter due to well-developed root branching, reached a maximum value and then decreased becouse of possible loss of lateral roots. On the contrary, the total number and length of nodal roots on main stems increased in the later growth stages followed by development of nodal roots emerged from tillers. Root branching of nodal roots was poorly developed compared with seminal roots. In the former growing period, most shallow roots consisted of seminal roots with well-developed laterals, whereris nodal roots increased to occupy a large portion in the later stages because of the increase in the total number of nodal roots as well as the decrease in the total length of seminal roots.

Distribution of genes for resistance to the wheatgrass mildew fungus in Japanese wheat cultivars and of their corresponding genes in the wheat mildew fungus

Distribution of genes for resistance to the wheatgrass mildew fungus in Japanese wheat cultivars and of their corresponding genes in the wheat mildew fungus

Distribution of genes for resistance to the wheatgrass mildew fungus in Japanese wheat cultivars and of their corresponding genes in the wheat mildew fungus.

Genotypes of Japanese wheat cultivars at loci for resistance to the twheatgrass mildew fungus, Erysiphe graminis f. sp. agropyri, were examined using the gene-for-gene relationship. Most cultivars carried two genes, Pm10 and Pm15 for resistance to the wheatgrass mildew fungus. Almost all cultivars were non-carriers of Pm11 and Pm14. On the other hand, all isolates of the wheat mildew fungus, E. graminis f. sp. tritici, collected from various areas in Japan were non-carriers of Ppm10, Ppm11, Ppm14, and Ppm15, avirulence genes corresponding to Pm10, Pm11, Pm14, and Pm15, respectively. From these results we suggest that the population of the wheat mildew fungus had lost Ppm11 and Ppm14 before its migration to Japan.

Gravitropic response growth angle and vertical distribution of roots of wheat (Triticum aestivum L.)

Recent work on root distribution, growth angles and gravitropic responses in Japanese cultivars of winter wheat are reviewed. Vertical distribution of roots, which influences the environmental stress tolerance of plants, was observed in the 12 Japanese cultivars in the field. The root depth index (RDI: the depth at which 50% of the root length has been reached) differed among the cultivars at the stem elongation stage. Since the RDI was closely related to the growth angle of seminal roots obtained in a pot experiment, it was assumed that growth angle is useful for predicting vertical root distribution among wheat genotypes. Gravitropic responses of the primary seminal root of 133 Japanese wheat cultivars assessed by measuring the growth angle in agar medium, were larger in the northern Japanese cultivars and smaller in the southern ones. It was also found that the geographical variation resulted from the wheat breeding process, i.e. genotypes with limited gravitropic responses of roots had been selected in the southern part of Japan where excessive soil moisture is one of the most serious problems.

Breeding of Candidate Lines for Male Sterility-Maintainer by Anther Culture for Hybrid Wheat Production Using an Sv Type Cytoplasm and a 1BL-1RS Chromosome.

We previously proposed a new breeding scheme to develop hybrid wheat utilizing male sterility induced by the interaction between the Svtype cytoplasm of Ae. kotschyi and the IBL-1RS chromosome (Toriyama et al. 1991, 1993). In our proposed scheme male sterility-maintainer lines can be produced by two ways, i. e. the backcrossing method (Nonaka et al. 1993) and anther culture. This article reports the results of anther culture. Donor for the 1BL-1RS chromosome, namely, the strain 911-B-8-10 (abbreviation, st. 911) was crossed to 13 Japanese wheat cultivars. The anther culture was conducted using the F1 and B1F1 plants. Frequency of embryo formation in the Fls was higher than that in the parental Japanese cultivars. The frequency observed in the B1F1s was lower than that in the F1s. High frequencies of embryo formation in st. 911 and the Fls were attributable in part to the 1BL-1RS chromosome. Since the leaf rust resistance gene Lr 26 was located on the 1RS chromosome arm, regenerated haploid seedlings were artificially inoculated by leaf rust (race 21B) to select resistant ones. Doubled haploids with resistance were crossed with (Sv)-Chinese Spring having the IB chromosome and with (Sv)-Salmon having the 1BL-1RS chromosome. The F1s of the former cross showed high selfed fertility, while the Fls of the latter showed complete male sterility. This means that resistant doubled haploids obtained by anther culture can be used as a maintainer for developing male-sterile line.

Identification of three Wx proteins in wheat (Triticum aestivum L.).

Nullisomic analysis of waxy (Wx) protein of hexaploid wheat (Triticum aestivum L.) cv. "Chinese Spring" using two-dimensional polyacrylamide gel electrophoresis revealed that three Wx loci, Wx-A1, Wx-B1, and Wx-D1, located on chromosome arms 7AS, 4AL, and 7DS, produce three distinct Wx subunit groups, subunit group-A (SGA), SGB, and SGD, respectively. SGA has a higher molecular weight and a more basic isoelectric point (pI) than the other two. SGB and SGD have the same molecular weight but a slightly different pI range. Owing to the detection of these three subunit groups, we were able to identify the expression of three waxy genes in wheat endosperm and to find two types of mutants among Japanese wheat cultivars, one lacking SGA and the others SGB. These results suggest the possibility of breeding a waxy wheat.

Effect of Water Potnetial of Culture Medium on Geotropic Response of Primary Seminal Root in Japanese Wheat Cultivars.

It has been observed that wheat has a shallow root system in wet soil and a deep root system in dry soil. However, the control mechanisms of root growth depending on soil water status remain unclear. Since root geotropic response seems to play an important role in the formation of the root system, the effect of water potential of culture medium on the geotropic response of the primary seminal root in Japanese wheat cultivars was examined. Agar medium with different concentrations of polyethylene glycol (PEG-6000) and vermiculite medium with different levels of water content were used. Growth angle of the primary seminal root in Minaminokomugi, which usually shows small root growth angle, became larger in low water potential media (-0.05 MPa) than in the control (O MPa). Effects of low water potential on root geotropic responses in the agar medium were also examined in 133 Japanese wheat cultivars. Minaminokomugi and 50 other cultivars showed large responses in the low water potential medium. It is considered that low water potential of the culture medium stimulates positive root geotropic responses in certain Japanese wheat cultivars.

Variations in the content of starch-granule bound protein among several Japanese cultivars of common wheat (Triticum aestivum L.)

The starch-granule bound proteins of common wheat (Triticum aestivum L.) and six related species were examined by SDS-polyacrylamide gel electrophoresis. They showed almost the same molecular weight, 61 kD. The amount of the starch-granule bound protein varied among Japanese wheat cultivars although the variation was not as wide as that for rice. The amount of this protein of Kanto 107 and Kanto 79 was about 40% of that of Norin 98. In addition, wheats with lower starch-granule bound protein also possessed lower amylose content.

Relation between Starch Granule Protein and Endosperm Softness in Japanese Wheat(Triticum aestivum L.)Cultivars.

Relation between Starch Granule Protein and Endosperm Softness in Japanese Wheat(Triticum aestivum L.)Cultivars.

Varietal differences in green plant regeneration ability of wheat pollen embryoids.

The present study was undertaken in order to clarify the effect of the culture media and the genotypes on the regeneration of green plantlets from pollen embryoids by anther culture of Japanese wheat cultivars. Pollen embryoids of 4 cultivars produced on Potato-2 medium were transferred onto two kinds of regeneration media (Table 1). On both media, embryoids grew into calli and then regenerated green or albino shoots and/or roots (Fig. 1 b and c). In rare cases, embryoids germinated (Fig. 1 a). The frequencies of green plantlets regenerated from embryoids differed with their genotypes even in the regeneration medium from 2.8% in Nanbukomugi to 33.5% in Chinese Spring. Moreover, the ability of embryoids to regenerate green plantlets was not affected by anther culture media, Potato-2 and C1 medium (Table 2). The effects of abscisic acid (ABA) on the embryoid formation and green plantlet regeneration were studied in anther culture of 7 cultivars (Table 3). ABA at a low concentration (0.1 and 0.5mg/l) had a stimulatory effect on the embryo formation in some cultivars which were genotypes of a rather low ability in embryoid formation, while ABA had a suppressive effect in other cultivars. However, ABA did not show a stimulatory effect on the regeneration of green plantlets in all cultivars tested. In conclusion, the ability of the green plantlet regeneration depended on genotypes regardless of the anther culture and regeneration media tested in this study: Norin 12 and Chinese Spring showed relatively high frequency of the green plantlet regeneration, while Hachimankornugi, Kitakarnikornugi and Norin 61 did not regenerate green plantlets. On chromosome constitutions of the regenerated green plants almost 659 were haploid (2n=21) and about 35% were diploid (2n=42) (Table 4, Fig. 2).

Efficiency of potato medium on induction of pollen embryoids in anther culture of Japanese wheat cultivars.

Efficiency of potato medium on induction of pollen embryoids in anther culture of Japanese wheat cultivars.

Crossability of Japanese wheat cultivars with Hordeum bulbosum L.

The crossabilities between Japanese wheat cultivars (Triticum aestivum L.) and tetraploid clones of Hordeum bulbosum L. were examined. In particular the effects of chemical agents on wheat crossability for improving crossing procedures in wheat haploid production were investigated. Twenty-two of the thirty-two wheat cultivars examined were crossable at frequencies of 10.4%-45.9% seed set. These crossable cultivars are genealogically derived from the progenies of crosses between Japanese local cultivars. The H.bulbosum genotypes used as pollinators also greatly influenced seed setting on wheat cultivar Fukuhokomugi with frequencies of 4.1%-50.0%However, non-crossability of Haruhikari could not be satisfactorily overcome when pollinated with the most promising clone of H. bulbosum. Crossing procedures with application of 2, 4-dichlorophenoxyacetic acid prior to pollination greatly increased seed setting on Fukuhokomugi, but did not appear to reduce effectively the incompatibility of Haruhikari. The present results suggest that this technique can be adopted to improve wheat haploid production using the bulbosum technique when crossable wheat genotypes are used as starting material.

Genealogical Pedigrees of Japanese Wheat Cultivars

Genealogical Pedigrees of Japanese Wheat Cultivars