INHERITANCE OF RESISTANCE TO NET BLOTCH IN BARLEY IN MOROCCO

Barley cultivars currently grown in Morocco do not have satisfactory r esistance to net blotch, caused by Pyrenophora teres. This study deter mined the inheritance of resistance in spring barley to net blotch in 11 F-2:5 populations in the field in Morocco. Three populations were e valuated in both the field and glasshouse to compare inheritance of re sistance of seedlings to single isolates in the glasshouse with natura l inoculum occurring in the field. In the field, resistance in cvs. He artland and Minn 7 was inherited in a monogenic manner in crosses invo lving moderately susceptible, susceptible, and highly susceptible cult ivars. The degree of susceptibility of the susceptible parent appeared to have little effect on the resistance level in the progeny. AC-SAD 176 and Anoidium had single resistance genes and Manchurian had two in dependent genes that conditioned resistance. Crosses among resistant c vs. Heartland, Minn 7, and ACSAD 176 segregated 7: 8: 1 (homozygous re sistant: segregating : homozygous susceptible) indicating different in dependent genes that condition resistance. Heartland appeared to posse ss a recessive gene that conditioned resistance to isolate I-12 in a c ross involving Rabat 071 and a dominant gene to isolate I-1 in crosses involving Arig 8 and ACSAD 176. Since resistance to P. teres in five cultivars was simply inherited, incorporation of these genes into barl ey adapted to Morocco should be feasible.