Abstract

Since sesame genotypes differed significantly in the levels of anti-nutritional factors (phytate, trypsin inhibitor and tannins), these anti-nutritional factors were examined as screening criteria for diseases resistance. Forty eight sesame genotypes from different sources were grown in soil infested by Fusarium oxysporum (FOS) and Macrophomina phaseolina (MPH) at Experimental Farm, Faculty of Agriculture, Suez Canal University, Egypt through two seasons (2009 and 2010) and approved for the above mentioned aim. The anti-nutritional factors of the tested sesame genotypes were associated significantly with both of infection pathogens percentages and seed yield. Most tested sesame genotypes were gathered in the scale of resistance (R) by scoring 48.90% and moderate resistance (MR) by scoring 40.7% of all the tested genotypes. On the other hand, 9.90% and 0.50% of the tested sesame genotypes were gathered in the scale of moderate susceptible (MS) and susceptible(S), respectively. Sesame genotype groups(resistant, moderately resistant, moderately susceptible and susceptible) were observed differenced significantly in their contents of the anti-nutritional factors. Most of the relationships among sesame genotype groups or among the anti-nutritional factorsand among themselves were showed significant correlations in both seasons (2009 and 2010) over the two fungal pathogens (FOS and MPH) together. The resistance (R) class possessed the highest values of the anti-nutritional factors, while the lowest values were related to the susceptible (S) class of sesame group. However, the other two classes, the moderately resistance and moderately susceptible possessed the medium values of phytic acid, trypsin inhibitor, and tannins over an average of the two seasons. Hence, these anti-nutritional factors could have played a clear role in the range and magnitude of resistance or susceptibility to fungal pathogens, F. oxysporumand M. phaseolina in sesame genotype groups considered in this work.

Key words: Disease resistance, Fusarium oxysporum, infection percentage,Macrophomina phaseolina, phytate, screening, seed yield, sesame, tannins, trypsin inhibitor.