Twelve F~ lines of barley were selected through !he crop breeding program of
desert research center under saline and rainted conditions. These elite newly bred
lines were chosen according to their superiority in abiotic (saline or drought) and biotic
(net blotcn disease) resistance. Signiflcant differences among all genotypes were
detected in respect to grain yield, 115 main components and nel blotch severity of
infection. Under Ras suder saline conditions, F~ line No.1 9ave the highest number of
spikes I plant (3.8) and il was bener than the check variety (Giza 123). Line (10)
(ollowed by line (9) and line (12) were the superior genotypes in 9rain yield I plant and
yielded more than the check variety (Giza 123) by 70.96, 69.87 and 65.94 %,
respectively. This superiority in yield potential was negatively correlated with severity
of net blotch Infection Posilive and significant correlation coefflcients were detected
between grain yield I plant and each of number of spikes I plant and 100 grain weight
which revealed that selection for each or both yi~ components would be
accompanied by high yielding ability under similar saline environments. One the other hand; under Maryout rainfed conditions, the three F~ selected
lines No. 12, 10 and 9 gave the highest grain yield J plant. These three lines
out yielded the recommended variety (Giza 126), by 73.48, 63.64 and 62.88 %
respectively. This superiority in yield potentiality mainly attributed to number of spIkes
I plant, 100-grain weight and tolerance to net blotch disease. Such elite newly bred
lines had p" in its genetic background which was developed for drought tolerance
under rainted Syrian conditions and selected as a hightv resistant genotype to net
blotch disease under Egyptian conditions. This finding may explain the importance of
the choice of parents in breading program. Small differences between phenotypic and genotypic coefficients of variability
for all trails were recorded except severity of net blotch disease infection suggesting
the relative importance of genetic variance lor such traits under both saline and
rainfall conditions. Accordingly, broad sense heritability estimates were relatively high
and ranging from 81.5 to 96.1 % and from 76.3 to 94.5 % under saline and rainfed
conditions, respectively.