Preliminary investigation in Beta germplasm in order to find accessions resistant to sugar beet powdery mildew
Sheikholeslami, M. | Koulivand, M. | Bassati, J. | Sadeghian, S.Y.
In order to evaluate and finding accessions resistant to sugar beet powdery mildew, some experiments were carried out from 1996 to 1999. First symptoms of disease appeared in late July and later observations indicated that there were 2 peaks in diagram of disease development, which the first one was in early August and the second one in early October. Appraisal method was based on estimating of leaf infection and calculation of average percent of leaf surface covered by powdery mildew. The number of genotypes were appraised in 1996 was 55, in 1997 was 50, in 1998 was 85 and in 1999 was 59. 16 genotypes was regarded as resistant conclusively. Results in 1996 also showed that although the onset of disease on all of accessions was identical but disease development on resistant accessions was slower than susceptible ones. The data obtained from evaluation of genotypes were analyzed through cluster analysis. Based on the results all of resistant genotypes were placed in one group. The accessions which showed an acceptable resistance in 1996 were: 14442, 10417, 10429, 23098 and 22919. In 1997 none of accessions showed resistance to the disease. In 1998 two accessions 23971 and 24302 showed resistance and in 1999 resistant genotypes were 14442, 10417, 23098, 24322 and 24746.
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