Three field experiments were carried out at Maryoul. Ras·Sudr and EL·
Maghara Stations, Desert Research Center, 2003 growing season to study the
genetic behavior of nine sorghum genctypes of the M,o generation for the severity
and incidence of leaf spot disease as well as to compare the fresh and dry forage
yield with the parental cunivar (Giza·1). Isozymes (polyphenol oxidase and
peroxidase) banding patterns and RAPO·PCR markers were used to genetically
identify the genotypes studied for disease resistance. The results obtained revealed
that genotypes differ significantly for forage yield at the three locations. however, the
genotypes M16, M48, M32 and M43 gave a significant trend for fresh and dry forage
yield compared with the parent cultivar (Giza-t), On the other hand, the results
showed that genotype M ·2 was the most resistant one for fungi disease severity if
compare 10 the parent cullivar lGiza·1) and the other genotypes among Ihe three field
experiments. Also. the results revealed that different gene expression levels in the
banding patterns when isozymes, which related to disease severity. For RAPO·PCR
analysis. six random arbitrary primers were used; the results showed that there are
polygel'letic relationships between the studied genotypes. Generally, the biochemical and molecular genetic analysis used in the
present study successfully distinguished the fungi disease resistance genotypes of
Sorghum blcolor L.