Evaluation of natural resistance of winter triticale cultivars to grain aphid using food coefficients

Five food coefficients were used to evaluate resistance of winter triticale cultivars against grain aphid Sitobion avenae (Fabr.). On the basis of the results of biochemical analysis the following coefficients were calculated : soluble carbohydrates-total nitrogen, soluble carbohydrates-free amino ac ids, soluble carbohydrates-protein amino acids, nonprotein amino acids-prot ein amino acids, nonprotein amino acids-free protein amino acids. The resul ts showed that the values of all coefficients for the 'Lasko' cultivar, whi ch is resistant to S. avenae, were higher than those of the susceptible 'Gr ado' cultivar. Applied tests of natural resistance of winter triticale, bas ed on biochemical properties of the plants, revealed considerable variabili ty of resistance of both cultivars to grain aphid. Thus, the tests may be v ery useful for preliminary selection of newly introduced strains and cultiv ars of winter triticale in respect of their resistance to grain aphid. The method may be also applied for a quick evaluation of new genetically engine ered products and the culture of highly aphid-resistant plants.