engleski

Recent developments in control of maize diseases through breeding

Within the maize breeding program, 63 inbreds and 62 maize hybrids were tested for resistance to leaf, ear and stalk diseases.Leaves were infected with now dominanat race 2 of Exserohilum turcicum, which is a result of a wide and continued usage of the Ht1 gene. Line resistance to E. turcicum ranged between 0,5 and 4,5. Early hybrids from maturity group 100 and 200 were more resistant in comparison with those from groups 300 and 400, in which a wide range of estimates, from 1,3 to 4,4, was obtained. Although Gibberella zeae, causing ear rot can appear sporadically in the world, it deserves attention because of the mycotoxins it produces. A large number of lines and hybrids was tested using for the first time a new Canadian method of artificial ear infection into the silk channel. Estimates obtained by a 1-7 scale varied from 1,0 to 5,1 for the lines and from 1,4 to 4,4 for the hybrids. Early hybrids proved to be resistant, wherease in groups 300, 400, 600, and 700 distinct differences in resistance were obtained. Because of the growing maize production in monoculture, Colletotrichum graminicola is spreading as a cause of anthracnose stalk rot. Resistance of inbred lines was estimated based on outer stalk discoloration (1-9), and it ranged between 1,3 and 8,0. The most susceptible hybrids were those in group 100 and 200 with 15,8 to 83,4 % of rotted plants. As a result of breeding for resisistance, new versions of the early lines, F2 and Bc 252, resistant to anthracnose stalk rot have been obtained.

anthracnose stalk rot; breeding for resistance; gibberella ear rot; hybrids; lines; maize; methods of artificial infection

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