Genetic distance (GD) among six maize inbred lines was determined based on the ISSR
markers. A total of 96 amplification bands were produced by ten ISSR primers; 35 out of them were
polymorphic (36.46 % polymorphism). Highest similarity level (94.3%) was between P2 and P3 that
are closely related. Highest genetic diversity was between P1 and P4. Inheritance of earliness, grain
yield and its components in three specific crosses (P2 x P3 low diversity, P5 x P6 moderate diversity
and P1 x P4 high diversity) were studied in a trial consisting of 6 populations (P1, P2, F1, F2, Bc1
and Bc2) during 2013 and 2014 years. Inbred line differences occurred regarding genetic
background, genetic variance within F2 population, desirable heterosis and inbreeding depression
were detected for all studied traits in the three crosses. Potence ratios were higher than unity
indicating over-dominance towards the desirable parent. Additive gene effects (a) and dominance
gene effects (d) were significant for most studied traits. High heritability in broad-sense was
detected, except for grain yield plant
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in cross No.1. Heritability in narrow-sense was low.
Variance in F2, mean performance in F1 and GCV% increased with increasing GD in the cross
P1xP4 followed by cross P5xP6 and then by cross P2xP3. Values of r were 0.98** between GD and
variance of F2, 0.97**between GD and mean performance of F1 and 0.79** between GD and
GCV% for grain yield plant
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. Hence,ISSR markers method proved powerful, reliable, fast and
inexpensive for screening genetic diversity between maize inbred lines. |
