Breeding potential of the backcross progenies of a hybrid between Trifolium medium × × T. pratense to T. pratense. Can. J. Plant Sci. 82: [395][396][397][398][399]. In this study, T. medium (zigzag clover, 2n = 80 and T. pratense (red clover, 2n = 28) were hybridized and backcrossed four times to T. pratense (BC 1 , BC 2 , BC 3 and BC 4 ), and the seed production and vigor of the backcross progenies were assessed under field conditions. Both female and pollen fertility of the backcross progenies increased as the backcross generations advanced. Female and pollen fertility of BC 4 were 21.3 and 65.3%, respectively. When honeybees were used as pollinators, almost all BC 4 plants produced mature seeds in the field. Most of the BC 1 , BC 2 , and BC 3 plants died by the end of the fourth year in the field, whereas 61% of the BC 4 plants survived for 4 yr. The number of chromosomes in 79% of the BC 4 plants was more than 28, which is greater than that of T. pratense. Mots clés: Rétrocroisement, matériel génétique, hybridation interspécifique, Trifolium medium, Trifolium pratenseTrifolium pratense L. (red clover) is an important forage legume in the northern part of Japan because it is easy to cultivate due to high adaptability to acidic and humid conditions. However, its usefulness is limited due to its lack of perenniality, which is a common deficiency of T. Pratense throughout the world. Introgression of genes for longevity from perennial Trifolium species to T. pratense is a potential means for improving the persistence of T. pratense. Various hybridizations with T. pratense have been carried out with several species: T. pallidum [Palestine clover (Armstrong and Cleveland 1970)], T. diffusum (Taylor et al. 1963;Schwer and Cleveland 1972), T. hirtum [Rose clover (Schwer and Cleveland 1972)], T. sarosiense Collins et al. 1983), T. alpestre [Purple glove clover (Merker 1988;Phillips et al. 1992)], and T medium [Zigzag clover (Merker 1982);Nedbalkova et al. 1995;Sawai et al. 1990Sawai et al. , 1995. Although many hybrids have been successfully produced, there have been no reports of hybrid plants being used as germplasm in conventional breeding programs. The reason for this lack of use is that the plants have not shown sufficient levels of fertility and vigor to justify employing them as practical breeding materials. Anderson et al. (1991) produced third backcross progenies of hybrids between T. ambiguum (Kura clover) × T. repens (White clover) to T. repens, and succeeded in increasing their fertility to a sufficient level for direct use in forage production. Their study showed that backcrossing is an effective means for increasing fertility and vigor.To introduce the rhizomatous growth habit and perenniality from T. medium to T. pratense, Sawai et al. (1995) obtained first and second backcross progenies of the hybrid between T. medium × T. pratense to T. pratense. The fertility of the backcross progenies increased as their generations advanced. However, neither the fertility nor the vigor were adequate for use in a ...

[1] The recent distribution of Russian hydrochemical data collected from the Arctic Basin provides useful information on ocean interior variabilities. Among various chemical components, silicate is the most valuable for showing the boundary between the silicate-rich Pacific Water and the opposite Atlantic Water. Here, it is assumed that the silicate distribution receives minor influence from seasonal biological productivity and Siberian Rivers outflow. It shows a clear maximum around 100-m depth in the Canada Basin. The vertical gradient below 100 m provides information on the vertical motion of the upper boundary of the Atlantic Water at a decadal time scale: i.e., the boundary shifts upward (downward), as realized by the silicate reduction (increase) at a fixed depth, responding to a more intense (weaker) Polar Vortex or the positive (negative) phase of the Arctic Oscillation. This valuable hydrochemical data set has provided a tool for verifying Arctic Ocean models with decadal responses to atmospheric variabilities. Citation: Ikeda, M., R. Colony, H. Yamaguchi, and T. Ikeda (2005), Decadal variability in the Arctic Ocean shown in hydrochemical data, Geophys. Res. Lett., 32, L21605,

Sunrouge is an anthocyanin-rich, new tea cultivar that contains similar levels of catechins as Yabukita, the most popular tea cultivar consumed in Japan. Interestingly, Sunrouge preparations have previously been shown to have more pronounced acetylcholinesterase inhibitory and anticolitis activities than those of Yabukita. In this study, we examined their effects on expressions of self-defensive molecules, including heat shock proteins (HSPs), which are molecular chaperones involved in homeostasis and longevity. Hot water extract from freeze-dried Sunrouge significantly upregulated messenger RNA (mRNA) expressions of HSP40, HSP70, and HSP32 (heme oxygenase-1), with grades greater than those shown by Yabukita. Oral administration of freeze-dried preparation of Sunrouge to male ICR mice at a dose of 1% in the basal diet for 1 month resulted in marked upregulations of several HSP mRNA expressions in mucosa from the gastrointestinal tract, especially the upper small intestine. Again, its efficacy was remarkably higher than that of Yabukita. Moreover, exposure of Caenorhabditis elegans to Sunrouge conferred thermoresistant phenotype, and also resulted in a significant life-span elongation. Taken together, our results suggest that Sunrouge is a unique and promising tea cultivar for regulating self-defense systems.

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