Screening for Drought Stress Tolerance in Wheat Genotypes Using Molecular Markers

Wheat that is one of the most important staple food crops in the world is adversely affected by
drought. Understanding its genetics and genome organization using molecular markers is of great
value for plant breeding purposes. Several screening tests were evaluated in the present research for
ability to estimate drought resistance in total 12 wheat genotypes including tolerant, semi-tolerant and
non-tolerant. Randomly Amplified Polymorphic DNA primers (RAPDs) associated with drought
tolerance were used initially to search genetic diversity in wheat plants. It was found out that primer
P6 (TCGGCGGTTC) produced respectively a 920-bp band present mainly in drought tolerant and
semi-tolerant (absent in sensitive) genotypes. Primer P7 (TCGGCGGTTC) produced a 750-bp band
that is not absolutely universal for our genotypes. Genome-wide investigation was also conducted
using Dreb l genes as an example. Five pairs of genome-specific primers designed for the wheat Dreb 1
genes were used for DNA amplification. Two primers, P21F/P21R and P25F/PR, amplified 596- and
I113-bp fragments, respectively, from the A gen ome. The PiSF/P18R primer amplified a 717-bp
fragment from the B genome. It was found out that Dreb 1 gene was located on chromosome 34A in all
genotypes, including drought-tolerant and drought-sensitive ones, excepting semi-tolerant gen otype
Tale-38. Contrary to other genotypes, a 717-bp PCR product of Dreb-BI gene was located on B
genome from drought-tolerant variety Barakatli-95. Primers P22F/PR and P20F/P20R that amnplify
596- and 1193-bp fragments, respectively, from D genome, that is common for hexaploid Triticum
aestivum L. genotypes, did not reveal positive results.