Studies on Haploid Breeding in Wheat (小麦の半数体育種に関する研究)
1. Tomohiko Ushiyama, Takao Shimizu and Tatsuo Kuwabara 1991. High Frequency of
Haploid Production of Wheat through Intergeneric Cross with Teosinte. Japanese Journal of
Breeding 41: 353-357.
Thirty nine genotypes of maize and one genotype of teosinte were investigated for the haploid production. Wheat x teosinte cross was the highest in frequency of embryo obtained ( 38.5%) and in haploid frequency per pollinated florets (31.5%). Teosinte can be used effectively in haploid breeding programs of wheat.
2．Effect of 2,4-Dichlorophenoxyacetic Acid on the Efficiency of Wheat Haploid Production by the Hordeum bulbosum method. PPS 9:206-211(2006). Tomohiko Ushiyama, Tatsuo Kuwabara and Tomohiko Yoshida
Abstract: Intergeneric crosses between Japanese wheat cultivars (Triticum aestivum L. cv. Nishikazekomugi and Zenkojikomugi) and a tetraploid wild barley, Hordeum bulbosum L. were used to examine the effect of treatment with 2,4-dichlorophenoxyacetic acid (2,4-D) on the formation of wheat haploid embryo and its development into plantlets. The detached wheat spikes with florets pollinated with H. bulbosum were cultured for 14 days in a sucrose and sulfurous acid solution to which 2,4-D was added at the concentrations of 0, 25, 50, 75, 100, 125, 150, and 175 mg L-1. (改行しない) The percentages of florets with seeds set and with embryos formed were increased by increasing the concentration of 2,4-D up to 100 mg L-1. Fourteen days after pollination, embryos (haploid) were isolated from the seed and cultured on agarose-solidified B5 medium. Embryo size tended to decrease as the concentration of 2,4-D increased, but the larger embryos tended to have higher ability to develop into haploid plants. The percentage of florets from which haploid plantlets were developed by embryo culture was slightly increased by the treatment of the spikes with 25-100 mg L-1 2,4-D, but significantly reduced by 125-175 mg L-1 2,4-D. It is suggested that treatment with 2,4-D at 25 - 100 mg L-1 would be effective for haploid wheat production by of H. bulbosum method.
3. Effects of various phytohormones on haploid wheat production in wheat x maize crosses
. T.Ushiyama, T.Kuwabara and T.Yoshida PPS 10(1):36-41(2007.1).
Abstract: The effects of phytohormones on the production of haploid wheat were examined in the intergeneric crosses between Japanese wheat cultivar (Triticum aestivum cv. Zenkojikomugi) and maize (Zea mays cv. Pioneer P80 Lisa). The detached wheat spikes pollinated with maize were cultured in a solution containing sucrose and sulfurous acid supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), indole-acetic acid, naphthalene acetic acid, kinetin or 6-benzylaminopurine at 0, 0.1, 1, 10, 100 or 1000 mg L-1. Haploid embryos obtained were cultured on agarose-solidified B5 medium. The frequency of plant regeneration was significantly affected only by the treatment with 100 mg L-1 2,4-D. Thus, the detached spikes were cultured in the media containing 2,4-D at 0, 25, 50, 75, 100, 125, 150, 175, 200 or 400 mg L-1. The treatments with 50 mg L-1 2,4-D increased the embryo size, but the treatments with above 75 mg L-1 2,4-D inhibited the development of the embryo. The percentage of florets developing into haploid plants was increased by the treatment with 100 mg L-1 2,4-D. Therefore, the concentration of 2,4-D in the spikes treated with 2,4-D at 50, 100 and 150 mg L-1 were measured by gas chromatography. The concentration of 2,4-D in the seed was increased to 9.24 ppm by the treatment with 100 mg L-1 2,4-D, a further increase of 2,4-D concentration in the medium having no effect. On the other hand, the concentration of 2,4-D in the glumes and rachis increased up to 12.72 and 41.55 ppm by the treatment with 100 and 150 mg L-1 2,4-D, respectively. The treatments with 2,4-D at a concentration higher than 100 mg L-1 inhibited embryo development. The present results suggested that 2,4-D at the concentrations from 50 to 100 mg L-1 would be optimum for haploid wheat production using maize.
4．Response to GA and variation of the culm length in doubled haploid lines of wheat
Tomohiko Ushiyama and Tomohiko Yoshida．PPS 11(2):217-222(2008.4)．
An F1 hybrid with the semi dwarf genes, Rht1 and Rht2, was crossed with Hordeium bulbosum and maize (teosinte) (bulbosum method and maize method) to produce doubled haploid (DH) lines, and 102 seedlings of each DH line produced by the two methods were treated with GA. The sensitivity to GA was shown by the GA index (GAI) which is (length of the first leaf sheath (LS) of GA-treated seedlings / length of LS of GA-non-treated seedlings) x 100. The scatter diagram of GAI plotted against culm length was divided into three groups, low, medium and high GAI groups. The segregation ratio of these gametophytic phenotypes was close to the expected ratio; 1:2:1 = Rht1Rht2 : (Rht1rht2+rht1Rht2) : rht1rht2, in both DH lines produced by the two methods. The frequency distribution of culm length in DH3, DH4, DH5 and DH6 populations from DH produced by the bulbosum method showed two peaks, though that in F3, F4, F5 and F6 populations from the same F1 hybrid (non-selective population) showed a continual normal distribution. The ratio of individuals with a shorter culm length to those with a longer culm length in DH lines was close to the expected ratio; 1:3 [ Rht1Rht2 : (Rht1rht2+rht1Rht2+rht1rht2)]. The frequency distribution of culm length in F6 was significantly different from that in F3-F5 populations, indicating an unintentional selection during the generation of the selfed hybrid, but the frequency of short culm relative to long culm individuals was lower in F3 ? F6 populations than in DH lines. These findings suggest the usefulness of selecting the medium culm-length lines in the DH lines produced by the bulbosum or maize method in addition of examining the GA sensitivity (GAI).
5.Pedigree Analysis of Wheat Cultivars Developed by Nagano Agricultural Experiment Station
Tomohiko Ushiyama, Kazuhiro Nakamura, Anas and Tomohiko Yoshida．PPS 12(1):80-87．
ABSTRACT: Pedigree analysis was conducted for wheat cultivars developed by Nagano agricultural experiment station (Tozan lines). For a recently released Tozan line, the maximum generation traced in the pedigree, total number of ancestors in the pedigree and total number of ancestors except common ones was 13, 222 and 94, respectively. Chunaga contributed 24.0 % of the genetic background of Tozan lines. Seven ancestors, collectively, contributed 51.5% to the gene pool. Hiyokukomugi had the highest mean coefficient of parentage to Tozan lines and the mean value was 0.216, followed by Kinuiroha (0.213), Norin 61 (0.206), Mikunikomugi (0.205) and Tokai 80 (0.194). The mean coefficient of parentage between Tozan lines and cultivars in Kanto and Tokai region, Kinki, Chugoku and Shikoku region and Kyushu region was 0.165, 0.155 and 0.157, respectively. Tozan lines more related to cultivars in Tohoku region tended to be late heading and more cold-tolerant. Tozan lines more related to Ayahikari or Kinuazuma tended to be early maturing. Fukuhokomugi, which was a high yield cultivar and often used as a cross parent did not contribute to high flour protein. KS831957 showed positive effect for crude protein content of flour. In general, Tozan lines had no specific cultivars used extensively as a cross parent having significant influence to yield or flour quality.