Evaluation of Some Faba Bean Genotypes against Chocolate Spot Disease Using cDNA Fragments of Chitinase Gene and Some Traditional Methods

Abstract

Thirteen faba bean (Vicia faba L.) genotypes were assessed under greenhouse and field conditions in 2008/2009 and 2009/2010 seasons, using morphological and molecular characterization methods for resistance to chocolate spot diseases caused by Botrytis fabae A significant variation among the tested genotypes and their reaction to the disease was found under greenhouse condition. Sakha 1, Sakha 2 and Nubaria-1 were resistant, indicating by the lowest disease severity. Whereas Giza 40, line 375 and Cairo 25 where susceptible. Other faba bean genotypes were moderately susceptible. Reverse-Transcription (RT-PCR) showed that Chitinase gene is expressed at early stages in infected faba bean leaves. By using of Chitinase specific primers DNA fragment at molecular weight 900 bp appeared at 48 hrs. in six faba bean genotype upon infection with the pathogen 48 hrs after inoculation and disappeared in the healthy plants. This fragment detected only in the resistance cultivars Sakha-1, Sakha-2 and Nubaria-1 and some moderate resistance genotype including Giza-3, line-24H and line 36. At the same time no signal was detected in other infected genotypes or healthy ones. Field results of testing genotype against chocolate spot diseases differed slightly than that of greenhouse. The estimates of heritability in broad sense ranged from 0.90 to 0.99, High values of heritability were obtained for seed yield/plant (0.99), followed by plant dry weight, plant height, seeds/pod across the two seasons. However, No relationship was found between resistance of genotypes against B. fabae and their morphological characterizes under field conditions. (Noha F. El-Badawy, M. M.Mazen, H. Abd El- Menem and S. R. E. Abo-Hegazy. Evaluation of Some Faba Bean Genotypes against Chocolate Spot Disease Using CDNA Fragments of Chitinase Gene and Some Agronomic Methods. J Am Sci 2012;8(8):241-250). (ISSN: 1545-1003). http://www.jofamericanscience.org. 36