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Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and
fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention
in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars
with high levels of resistance has been hampered by the lack of sources of strong resistance in the cultivated tomato and
by the quantitative expression and polygenic inheritance of the resistance. In some accessions of wild species, high levels
of early blight resistance have been found, but breeding lines still have unfavorable horticultural traits from the donor
parent. Recently, the first linkage maps with loci controlling early blight resistance have been developed based on interspecific
crosses. These maps may facilitate marker-assisted selection. This overview presents the current knowledge about the A. solani–tomato complex with respect to its biology, genetics, and breeding. 相似文献
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The behavior of estrone (E1) and 17??-estradiol (E2) in relatively closed water environment was studied by continuous flow experiment using sediments from a freshwater reservoir. For this, four sediment columns (two oxic ones and two anoxic ones) were employed, which were structured by packing 30?cm of undisturbed sediment and 60?cm of overlying water collected from two sites within a reservoir. A mass balance model that considered the influent flux, the effluent flux, mass transfer, sorption, and biodegradation was proposed to describe the behavior of E2 and E1 in the columns. The results indicated that the water?Csediment partition coefficient of E1 $ \left( {K_{\text{d}}^{\text{E1}}} \right) $ was higher than E2 $ \left( {K_{\text{d}}^{\text{E2}}} \right) $ . The degradation rate of E1 (k E1) was smaller than E2 (k E2). Under both oxic and anoxic conditions, E1 was formed from E2. Furthermore, to clarify the impact of the model parameters such as the hydraulic retention time (HRT), K d, and k on the behavior of E2 and E1, variance analysis was performed based on the results of model simulations. The results showed that the concentrations of E2 and E1 in the column effluent were controlled most significantly by the sorption capacity of the natural estrogens onto sediment particles, with the determined contributory ratios changing in the order of sorption > HRT > degradation. 相似文献
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Reni Chaerani Remmelt Groenwold Piet Stam Roeland E. Voorrips 《Journal of General Plant Pathology》2007,73(2):96-103
A droplet inoculation method was used for evaluation of tomato resistance to early blight, a destructive foliar disease of
tomato caused by Alternaria solani (Ellis and Martin) Sorauer. In this test method, leaflets are inoculated with small droplets of a spore suspension in either
water or a 0.1% agar solution. Early blight resistance was evaluated based on lesion size. The droplet method better discriminated
the level of resistance (P < 0.001) for a range of spore densities in comparison with the more commonly used spray inoculation method. Lesions generated
by droplet inoculation at 7 days after inoculation ranged from small flecks to almost complete blight with an exponential-like
distribution of lesion sizes. Significant correlations (r = 0.52, 0.58, and 0.63, P < 0.001) were observed across three glasshouse tests of 54 accessions including wild species using the droplet method. The
most resistant accessions included wild species: one accession of Solanum arcanum, three accessions of Solanum peruvianum, one accession of Solanum neorickii, and one of Solanum chilense. Solanum pennellii and Solanum pimpinellifolium accessions were susceptible, whereas Solanum habrochaites and Solanum lycopersicum accessions ranged from susceptible to moderately resistant. The droplet test method is simple to apply, offers a fine discrimination
of early blight resistance levels, and allows objective evaluation. 相似文献
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Tri Asmira Damayanti Desmiarti Susilo Siti Nurlaelah Dewi Sartiami Tetsuro Okuno Kazuyuki Mise 《Journal of General Plant Pathology》2008,74(6):438-442
Severe mosaic with leaf malformation and green vein banding was observed on yam bean in West and Central Java, Indonesia.
Virions of the causal virus were flexuous filaments, about 700 nm in length, with a coat protein of 30 kDa. The virus was
transmitted by mechanical inoculation and by aphids in a nonpersistent manner. The nucleotide sequence of the coat protein
gene had the highest identity with that of Bean common mosaic virus (BCMV, genus Potyvirus) isolate VN/BB2-5. Based on demarcation criteria, including the genome sequence and host range, we tentatively designate
this isolate as BCMV-IYbn (Indonesian yam bean).
The nucleotide sequence reported is available in the DDBJ/EMBL/GenBank databases under accession number AB289438. 相似文献
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