Journal of Weed Science and Technology
Online ISSN : 1882-4757
Print ISSN : 0372-798X
ISSN-L : 0372-798X
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Volume 56, Issue 2
Displaying 1-8 of 8 articles from this issue
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Reports
  • Characterization of Vulpia myuros (L.) C.C. Gmel. var. megalura (Nutt.) Rydb. and Vulpia myuros (L.) C.C. Gmel. for sod culture from heading and germination properties
    Keiko Nakatani, Ken Hashizume, Takasi Haji, Tomoko Shibuya, Shigenori ...
    2011 Volume 56 Issue 2 Pages 75-80
    Published: 2011
    Released on J-STAGE: September 09, 2011
    DOIhttps://doi.org/10.3719/weed.56.75
    JOURNAL FREE ACCESS
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    To distinguish foxtail fescue (Vulpia myuros (L.) C.C. Gmel. var. megalura (Nutt.) Rydb.) and rattail fescue (Vulpia myuros (L.) C.C. Gmel.) as sod culture plants employed in orchards, we compared the heading and germination characteristics of these plants. The headings of foxtail fescue were observed 3 weeks earlier than those of rattail fescue under natural conditions at both examination sites:Tsukuba (N36°) and Morioka (N39°) in Japan. In a growth chamber, we observed the heading of foxtail fescue under 10, 13, and 16 hour photoperiods without seed pre-treatments. In contrast, inducing the heading of rattail fescue required a 16-hour photoperiod and low temperature (5°C) pretreatments of imbibed seeds for more than 30 days. Thus, we consider rattail fescue an apparent LD plant that also needs low temperature for heading.
    The optimum temperature for seed germination was observed to be 10-25°C in these plants. Since relatively active germinations were observed in foxtail fescue at sub optimum temperatures (5°C and 30°C), we regard foxtail fescue to have higher allowance regarding germination temperature. For both plants, almost all imbibed seeds (>97%) survived after low-temperature treatment (−3°C) for 3 weeks. Since high-temperature treatment (35°C) of imbibed seeds for 3 weeks killed 31% of rattail fescue seeds and 12% of foxtail fescue seeds, we consider rattail fescue to have higher heat tolerance.
    Although foxtail fescue and rattail fescue are closely related plants, they show different ecological characteristics that are important to consider for introduction to sod culture in Japan.
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  • Effects of low-branching cultivars, narrow-row spacing and herbicides on weed control in soybean in the Tokachi area of Hokkaido.
    Shizuko Ishikawa
    2011 Volume 56 Issue 2 Pages 81-88
    Published: 2011
    Released on J-STAGE: September 09, 2011
    DOIhttps://doi.org/10.3719/weed.56.81
    JOURNAL FREE ACCESS
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    In order to establish an integrated weed control system for low-branching soybean cultivars suitable for mechanical-harvesting in the Tokachi area of Hokkaido, we surveyed weed species in the soybean fields of three farmers in 2003. Also, we conducted field experiments in 2005 and 2006 to determine the effects of combinations of narrow-row spacing and herbicides for weed control. In the farmers' fields, eighteen weed species were recorded, among which Parsicaria nepalensisi (Meisn.) H. Gross was most frequent weed. Pre-emergence application of linuron (0.75kg a.i./ha) plus trifluralin (0.89kg a.i./ha) did not suppress the emergence of Parsicaria nepalensis even in 30-cm rows. Post-emergence directed application of bialaphos (0.54 kg a.i./ha) in combination with soil applied herbicides provided good control of Parsicaria nepalensis. Bialaphos treatment with a dedicated sprayer for post emergence directed application caused no yield reduction in 30-cm row soybeans. These results demonstrate that pre-emergence directed applications of linuron and trifluralin and post-emergence directed applications of bialaphos are the most effective weed management systems for low-branching soybean cultivars in narrow-rows.
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  • Inheritance for sensitivity of high-yielding rice cultivars, ‘Momiroman' and ‘Takanari', to benzobicyclon, a 4-HPPD inhibitor
    Maiko Akasaka, Hiroaki Watanabe, Yoshiaki Kawana
    2011 Volume 56 Issue 2 Pages 89-94
    Published: 2011
    Released on J-STAGE: September 09, 2011
    DOIhttps://doi.org/10.3719/weed.56.89
    JOURNAL FREE ACCESS
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    In order to clarify the inheritance for susceptibility in ‘Momiroman' and ‘Takanari', the high-yielding rice cultivars, to benzobicyclon, a 4-HPPD inhibiting rice herbicide, segregations of the susceptibility was analyzed in F2 generations of reciprocal crosses between the two cultivars and ‘Nipponbare'. The two cultivars, ‘Momiroman' and ‘Takanari' were clearly diagnosed susceptible and ‘Nipponbare' was diagnosed tolerant to the herbicide by double dosage treatment of a commercial one-shot herbicide, 1kg granule containing pyrazosulfuron-ethyl, fentrazamide and benzobicyclon, one day after transplanting of the two-leaf stage rice seedlings, 1kg granule of pyrazosulfuron-ethyl and fentrazamide combination. The segregations of the susceptibility in F2 generation obtained by the herbicide treatment were analyzed using chi-square test. The result revealed that the tolerant/susceptible segregations were fitted a 3:1 ratio. It is suggested that a susceptible trait of the two high-yielding rice cultivars to benzobicyclon is dominated by a recessive oligogene in nuclear, and is no evidence of cytoplasmic inferitance.
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The Society Award Lectures
Review
  • Effectiveness of weed control technology using crops genetically modified for herbicide tolerance (GEHT) —In case of United State of America
    Ryuichi Sago
    2011 Volume 56 Issue 2 Pages 104-110
    Published: 2011
    Released on J-STAGE: September 09, 2011
    DOIhttps://doi.org/10.3719/weed.56.104
    JOURNAL FREE ACCESS
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    Internationally, farmers planted 134 million hectares of genetically modified (GM) corn, soybeans and cotton in 2009. Crops genetically modified for herbicide tolerance (HT) accounted for 85% of GM crops planted. The majority of HT crops are glyphosate tolerant (RR) soybean, corn or cotton. HT crop cultivation in the USA began in 1996;however, HT crops in Japan are not yet cultivated commercially. This paper discusses the effectiveness of weed control technology on HT crops in Japan. Glyphosate resistant weeds are spreading widely in HT crop fields in the USA. Because of the widespread of glyphosate-resistant weeds, the use rate of glyphosate herbicide and the use of herbicides with other modes of action have vastly increased in RR soybean, RR corn and RR cotton fields. GMHT technology has only succeeded in prolonging the use of glyphosate herbicide, but has not solved the weed problem. Therefore, the necessity for GMHT crops in Japan is low, because the area of conservational tillage is small and farmers use herbicides systematically. It is now abundantly evident that there is a necessity for the development of herbicides with new modes of action.
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Technical Report
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