Rapd-markers for yield ability and disease resistance in barley under rainfed conditions

Abstract EN

Fifteen genotypes comprised one exotic, two local check varieties and twelve newly bred lines produced through the Desert Research Center (DRC) barley breeding program were grown during two successive seasons ended in 2003/2004 at Maryout experimental farm of DRC.

The aim of this study is to obtain reliable molecular markers for drought tolerance and disease resistance in such genotypes.

In the second season, grain yield /plant for the hulled grains type ranged from 3.71g for Giza 126 G126) to 6.18g for line3.

Meanwhile, H10 was the best yielded (7.08 g) and Giza 131 gave the relatively lowest grain yield/plant (2.69g) among the hulles grains genotypes under tested rainfall conditions.

Also the highest grain yielding ability (newly bred hulles grains line, H10) showed highly resistance for both parameters of net blotch disease (D.S and D.I).

In respect to disease occurrence, genotypes P4 and G126 were moderately resistant to net blotch disease where disease severity recorded 50 % and 43.3, % respectively.

Whereas, lines 26, Mar19A, 8, and H10 were resistant. RAPD banding pattern for the five primers were scored seven negative molecular markers which were exhibited in the relatively sensitive barley variety G126 and ten positive molecular markers which appeared in the tolerant line3.

On the other hand, lines 8 and 25 (the two high yielding hulled newly bred lines) seemed to be a drought tolerant genotypes as it had a positive molecular markers (820 bp) for operon primer O4 and 937 bp for operon primer O10.

Also, line 25 had a positive molecular marker of operon primer Z4 (3000 bp) for high yielding ability under tested rainfall conditions The negative markers can be used as indicators to discard the newly bred line 24 as it designed in the lowest yielding barley group and had a negative marker (1032 bp) for O10 operon primer. The two Z operon primers differentiate hulls grains barley genotypes by five positive markers for drought tolerance and net blotch disease resistance. Interestingly, many bands were shown to appear in the tolerant hulls barley lines (H2, H6, and Mar19A).

Also, similar bands were present in Z4 and Z7 operon primers.

For this reason, results of both positive and negative molecular size (bp) against different primers indicated that RAPD markers are dominant.