Assessment and identification of alfalfa clones resistance to alfalfa witches' broom in Yazd province.
2009
Tabatabaei, A`li | Esmaeil Zadeh Hosseini, A`li Reza | Ja`fari Nodushan, A`li | Mohammadi Nezhad, Qasem | Qayumi, Mohammad | Izadi Far, Mohammad | Izad Panah, Keramat Ol-Lah
Alfalfa witches'broom (AWB) is one of the most important alfalfa diseases in Iran. To identify alfalfa clones tolerant or resistant to AWB, during 2004-2008 a survey was conducted in the major alfalfa growing regions of Yazd province. Based on characteristic disease symptoms, ELISA test using polyclonal antiserum and polymerase chain reaction using P1/P7 and R16F2n/R16R2 primer pairs, healthy plants were separated from symptomatic and asymptomatic infected plants. Clones of healthy plants were cultured in row planting in Rezwanshahr (Sadugh, Yazd province) and infection percent and diseases severity were evaluated. Furthermore, healthy clones inoculated with AWB phytoplasma using Orosius albicinctus leafhopper vector. Under laboratory condition thousand kernel weight, germination percent, radicle length, plumule length, radicle dry weight and plumule dry weight of tolerant plants were examined in Petri dish. Based on the results of this study 18.7% of plants in perennial alfalfa stand had field resistance. 3.85% of healthy clones were not infested in inoculation trials. Seeds of tolerant plants had low germination percent and plant vigorous compared to healthy plants. Considering to the results, using healthy plants for producing seed is recommended. Because of the low germination percent and low plant vigorous, it is not recommended to use the seeds of tolerant plants.
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