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INHERITANCE ASSESSMENT OF CHOCOLATE SPOT  AND RUST DISEASE TOLERANCE IN MATURE FABA BEAN (VICIA FABA L.) PLANTS

IJAZ RASOOL NOORKA AND M.A.S. EL-BRAMAWY

Abstract: The major aim for any crop breeding program is the development of good quality lines with an adequate resistance/tolerance to yield-reducing stresses. Fungal diseases i.e., chocolate spot (Botrytis fabae Sard) and rust (Uromyces fabae (Pers.) Schart) are the most destructive diseases of faba bean and cause considerable dramatic damage losses on faba bean yield worldwide. Therefore, the use of breeding efforts by studying the mode of inheritance of resistance to both diseases (chocolate spot and rust) in Vicia faba, give evidence for the existence of one or more genes controlling the resistance of these diseases. Identifying the mode of inheritance of field resistance to chocolate spot (B. fabae) and rust (U. fabae) diseases in Vicia faba at the adult plant stage was considered in this work. The F₁’s, F₂’s and F₃’s off-spring of resistant and susceptible faba bean plants were assessed under natural infection in a private field in Ismailia Governorate, Egypt, from the period of mid October to mid April in two successive sesaons (2007/08 and 2008/09). The faba bean plants were evaluated for the resistance to chocolate spot (B. fabae) and rust (U. fabae) diseases at maturity stage using a five-class scale of increasing susceptibility to the disease, which took into account the number of infected leaves and the size of the sporulating lesions. The results exhibited that the F₁’s was completely resistant to both the diseases, the F₂’s segregated a clear 3 resistant: 1 susceptible, while the F₃’s confirmed the F₂’s segregation, which suggests that a dominant character controlled by a single locus. This resistance has well potencial for direct use in commercial faba bean breeding or for transfer to other faba bean gemplasm.

¹Department of Agronomy, Faculty of Agriculture, Suez Canal University, Ismailia, 41522, Egypt

²Department of Botany, Faculty of Sciences, Suez Canal University, Ismailia, 41522 Egypt

³Department of Plant Breeding, Genetics and Molecular Biology, University College Agriculture, University of Sargodha, Sargodha, Pakistan