EVALUATION OF ALFALFA CULTIVARS GROWN IN SAUDI ARABIA FOR RESISTANCE TO AG4 OF Rhizoctonia solani KUHN

A. A. Al-Doss*, S. Al-Kherb** and S. El-Hussieni**

* Plant Production Dept. King Saud Uni. Riyadh

** Plant Protection Dept. King Saud Uni. Riyadh

 

ABSTRACT

Rhizoctonia solani Kuhn causes root canker and root rot in Alfalfa growing areas in Saudi Arabia. Ten Alfalfa cultivars were evaluated for damping-off, disease severity and resistance to Rhizoctonia solani AG4. Results of damping-off of R. solani AG4 on alfalfa seedlings indicated that all landraces and imported varieties were highly susceptible.  The Egyptian cultivar was the most resistant cultivar to R. solani AG4 root canker, while the local cultivars Qassimi and Hasawi  along with the introduced cultivars CUF 101, Panner 4860 and Serosal were moderately resistant, on the other hand the other tested cultivars were susceptible. Measurments of plant growth characteristics of the ten tested alfalfa cultivars indicated that the effect of R. solani AG4 was mainly on root fresh weight. This study revealed that most cultivars grown in Saudi Arabia are susceptible to R. solani AG4 which emphasize the need for breeding local cultivars resistance to  soil born diseases such as root canker and root rot caused by R. solani.