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Hori K.,Japan National Institute of Agrobiological Science | Sugimoto K.,Japan National Institute of Agrobiological Science | Nonoue Y.,Institute of the Society for Techno innovation of Agriculture | Ono N.,Institute of the Society for Techno innovation of Agriculture | And 5 more authors.
Theoretical and Applied Genetics | Year: 2010

Backcrossed inbred lines (BILs) and a set of reciprocal chromosome segment substitution lines (CSSLs) derived from crosses between japonica rice cultivars Nipponbare and Koshihikari were used to detect quantitative trait loci (QTLs) for pre-harvest sprouting resistance. In the BILs, we detected one QTL on chromosome 3 and one QTL on chromosome 12. The QTL on the short arm of chromosome 3 accounted for 45.0% of the phenotypic variance and the Nipponbare allele of the QTL increased germination percentage by 21.3%. In the CSSLs, we detected seven QTLs, which were located on chromosomes 2, 3 (two), 5, 8 and 11 (two). All Nipponbare alleles of the QTLs were associated with an increased rate of germination. The major QTL for pre-harvest sprouting resistance on the short arm of chromosome 3 was localized to a 474-kbp region in the Nipponbare genome by the SSR markers RM14240 and RM14275 by using 11 substitution lines to replace the different short chromosome segments on chromosome 3. This QTL co-localized with the low-temperature germinability gene qLTG3-1. The level of germinability under low temperature strongly correlated with the level of pre-harvest sprouting resistance in the substitution lines. Sequence analyses revealed a novel functional allele of qLTG3-1 in Nipponbare and a loss-of-function allele in Koshihikari. The allelic difference in qLTG3-1 between Nipponbare and Koshihikari is likely to be associated with differences in both pre-harvest sprouting resistance and low-temperature germinability. © 2010 The Author(s).

Imaizumi T.,Japan National Agricultural Research Center | Kataoka Y.,Akita | Ogata S.,Iwate Agricultural Research Center | Uchino A.,Japan National Agricultural Research Center
Weed Research | Year: 2013

To reveal the effects of herbicide selection on genetic diversity in the outcrossing weed species Schoenoplectus juncoides, six sulfonylurea-resistant (SU-R) and eight sulfonylurea-susceptible (SU-S) populations were analysed using 40 polymorphic inter-simple sequence repeat loci. The plants were collected from three widely separated regions: the Tohoku, Kanto and Kyushu districts of Japan. Genetic diversity values (Nei's gene diversity, h) within each SU-S population ranged from h = 0.125 to h = 0.235. The average genetic diversity within the SU-S populations was HS = 0.161, and the total genetic diversity was HT = 0.271. Although the HS of the SU-R populations (0.051) was lower than that of the SU-S populations, the HT of the SU-R populations (0.202) was comparable with that of the SU-S populations. Most of the genetic variation was found within the region for both the SU-S and SU-R populations (88% of the genetic variation respectively). Two of the SU-R populations showed relatively high genetic diversity (h = 0.117 and 0.161), which were comparable with those of the SU-S populations. In contrast, the genetic diversity within four SU-R populations was much lower (from h = 0 to 0.018) than in the SU-S populations. The results suggest that selection by sulfonylurea herbicides has decreased genetic diversity within some SU-R populations of S. juncoides. The different level of genetic diversity in the SU-R populations is most likely due to different levels of inbreeding in the populations. Weed Research © 2013 European Weed Research Society534 August 2013 10.1111/wre.12027 Original Article Research Papers © 2013 The Authors Weed Research © 2013 European Weed Research Society.

Yamaguchi T.,Iwate Agricultural Research Center
Acta Horticulturae | Year: 2012

In Japan, asparagus ferns undergo yellowing in autumn, and the germination of the buds is suppressed even when they are exposed to optimum temperatures. This phenomenon is called "dormancy", and low temperatures are necessary for breaking dormancy. To harvest asparagus during winter, forcing culture is performed in part by using dug rootstocks. This method is called "Fusekomi forcing culture". While the major factor affecting the induction of dormancy is the cumulative exposure to chilling temperatures, the photoperiod is also considered to be a possible factor affecting the induction of dormancy. In this study, we investigated the effect of short-day photoperiod on asparagus growth in autumn by using 1-year-old 'Welcome' plants. The plants were sown in early February and grown in non-woven fabric pots with a diameter of 25 cm. From late August, these pots were subjected to 8-h short-day photoperiod (SD) or natural photoperiod (ND; average time, 12 h 06 min). After the treatment, the pots were placed in a greenhouse, and the soil temperature was adjusted to 16°C. There was no difference between the yellowing of asparagus ferns in the SD- and ND-treated plants. The number of stems in the SD-treated plants was slightly greater than that in the NDtreated plants; the plant height in the former group was lower than that in the latter group. The brix value of the root increased with time; the value for the ND-treated plants was greater than that for the SD-treated plants. The root weight showed a similar trend. However, if the temperature of the surroundings is suitable for breaking bud, SD and ND treatments do not have any difference. On the basis of these results, we believe that the dormancy of 1-year-old asparagus in autumn was not influenced by short-day conditions; rather, it was affected only by the reduction in photosynthesis.

Okuyama Y.,Iwate Biotechnology Research Center | Kanzaki H.,Iwate Biotechnology Research Center | Abe A.,Iwate Agricultural Research Center | Yoshida K.,Iwate Biotechnology Research Center | And 10 more authors.
Plant Journal | Year: 2011

The Oryza sativa (rice) resistance gene Pia confers resistance to the blast fungus Magnaporthe oryzae carrying the AVR-Pia avirulence gene. To clone Pia, we employed a multifaceted genomics approach. First, we selected 12 R-gene analog (RGA) genes encoding nucleotide binding site-leucine rich repeats (NBS-LRRs) proteins from a region on chromosome 11 that shows linkage to Pia. By using seven rice accessions, we examined the association between Pia phenotypes and DNA polymorphisms in the 10 genes, which revealed three genes (Os11gRGA3-Os11gRGA5) exhibiting a perfect association with the Pia phenotypes. We also screened ethyl methane sulfonate (EMS)-treated mutant lines of the rice cultivar 'Sasanishiki' harboring Pia, and isolated two mutants that lost the Pia phenotype. DNA sequencing of Os11gRGA3-Os11gRGA5 from the two mutant lines identified independent mutations of major effects in Os11gRGA4. The wild-type 'Sasanishiki' allele of Os11gRGA4 (SasRGA4) complemented Pia function in both mutants, suggesting that SasRGA4 is necessary for Pia function. However, when the rice cultivar 'Himenomochi' lacking Pia was transfected with SasRGA4, the Pia phenotype was not recovered. An additional complementation study revealed that the two NBS-LRR-type R genes, SasRGA4 and SasRGA5, that are located next to each other and oriented in the opposite direction are necessary for Pia function. A population genetics analysis of SasRGA4 and SasRGA5 suggests that the two genes are under long-term balancing selection. © 2011 Blackwell Publishing Ltd.

Abe K.,Japan National Institute for Agro - Environmental Sciences | Nakamura K.,Sumika Chemical Analysis Service Ltd | Arao T.,Japan National Institute for Agro - Environmental Sciences | Sakurai Y.,Japan National Institute for Agro - Environmental Sciences | And 4 more authors.
Journal of the Science of Food and Agriculture | Year: 2011

A simple and quick on-site test for trace levels of cadmium (Cd) in food is needed because of the human toxicity of this heavy metal. We developed an immunochromatography kit which uses the antigen-antibody complex reaction between the Cd-ethylenediaminetetraacetic acid (Cd-EDTA) complex and an anti-Cd-EDTA antibody. We previously reported the successful use of this kit to determine Cd concentrations in brown rice with respect to the international standard: 0.4 mg kg -1. Here, we measured, using this immunochromatography kit, Cd concentrations in crops with lower international standards than rice. RESULTS: Cadmium extracted with 0.1 mol L -1 HCl from wheat grain and fresh eggplant was purified sufficiently using an ion-exchange column treatment. Appropriate HCl extraction rates and dilution rates for the column eluate were selected; Cd concentrations in wheat grain and fresh eggplant were determined successfully by immunochromatography with respect to the international standards of 0.2 mg kg -1 and 0.05 mg kg -1 fresh weight, respectively. CONCLUSION: Approximate Cd concentrations in wheat grain and fresh eggplant can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. © 2011 Society of Chemical Industry.

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