جستجوی مقالات مرتبط با کلیدواژه « آنتراکنوز » در نشریات گروه « گیاهپزشکی »

Bean anthracnose disease caused by Colletotrichum lindemuthianum is one of the most important bean diseases in Iran. In this study, the presence of disease resistance genes was investigated using SCAR primers in 12 Iranian bean cultivars. Also, disease symptoms were evaluated based on the disease severity index in the greenhouse condition. Amplification of SCAR markers SAS13, SY20, SZ04 and SB12 indicated the presence of Co-42, Co-4, Co-6 and Co-9 resistant genes respectively. Cultivars Akhtar, Derakhshan, Almas, Talash and Koosha contained Co-42, Co-4 and Co-6 resistance gene revealed by amplification of SBB14, SC08 and SZ20 markers accordingly. Co-42 gene was detected in Goli and Naz cultivars and Co-4 and Co-42 genes were present in Pak, Sadri and Khomein cultivars. Co-42 gene that is linked to SH18 marker was observed in Dorsa and Shokofa cultivars. The presence of Co-2 resistance gene was observed only in Almas cultivar. Co-5 gene linked to SAB3 marker was only observed in the related differential cultivars. Phenotypic evaluation for disease symptoms showed that out of 12 cultivars studied, four (Naz, Almas, Dorsa and Shokofa) showed resistance reaction and two (Akhtar and Goli) were moderately resistant. Based on the disease severity index, these cultivars were considered relatively resistant. Simultaneous analysis of molecular and phenotypic data showed that only the two markers of SQ4 and SH18 succeeded in band amplification in resistant cultivars Diamond, Shokofa and Dorsa. The results of this study will be of help in producing resistant bean cultivars to anthracnose disease by resistance gene pyramiding.

In this study survivability, morphological characteristics and pathogenicity of 12 isolates of Ophiognomonia leptostyla, which is known as causal agent of walnut anthracnose, have been evaluated after 13-years of storage on filter paper in oat meal agar (OMA) and -20°C. The recovery rate varied from 0 to 89 percent and seventy-five percent of stored isolates were shown to be viable. In macroscopic and microscopic studies of revived cultures, the morphology of colonies was uniform for all isolates. Production of asexual bodies (acervular conidiomata) was preserved by all isolates. Fertile perithecia with asci and ascospores were not detected in pure fungal cultures after three months incubation at 8-10°C in darkness. In pathogenicity experiments, there was not a significant variability in infection severity for different isolates, and the first symptoms were observed on leaves 12-16 days after inoculation. Stability of morphological characteristics, ability to sporulation and retaining the pathogenicity of isolates confirmed that transferring of acervuli on filter paper in OMA medium could be a suitable, safe, simple and cost-effective tool to preserve O. leptostyla isolates in a viable state.