SOURCES OF RESISTANCE TO COMMON BUNT (TILLETIA-FOETIDA AND TILLETIA-CARIES) IN DURUM-WHEAT

Screening of durum wheat germplasm for resistance to common bunt (Till etia foetida and T. caries) resulted in the identification of 26 resis tant genotypes. The screening was made using nine common bunt isolates from the West Asia and North Africa (WANA) region. In one isolate the two pathogens were represented in ratio of 1:1, whereas eight isolate s contained only T. foetida. The correlation, principal components and clustering analyses grouped the genotypes into three clusters. Cluste r one comprised genotypes with genetic interrelationship with Jennah K hetifa, a Maghrebian landrace. Cluster two comprised genotypes close t o Senatore (S.) Cappelli and Haurani, the latter is a landrace from Sy ria. Cluster three comprised advanced genotypes containing resistance genes from Mindum, a Turkish landrace. Results indicated that donor so urces of resistance appear to be related to the three major sources me ntioned. Cultivar S. Cappelli is considered resistant since it has bee n grown by farmers on a large scale for many years and remained resist ant to common bunt throughout 7 years of testing. This resistance is a ssumed to be of a durable type. The isolates were also grouped into th ree clusters representing different ecological areas and the wheat typ es from which the isolates originated. We infer that the different clu sters reflect the presence of three pathotype groups of the pathogens.