Genetic diversity among some Egyptian bread wheat cultivars based on morphological characters and ssr markers

الملخص EN

The fundamental objective of any successful breeding program is releasing divergent cultivars adapted to every region’s requirements all over the country.

The traditional method for estimating genetic diversity is morphological characterization.

The polymorphism based DNA characterization recently has been emerged as a suitable tool in estimating genetic diversity.

The present study included 14 Egyptian bread wheat cultivars.

This investigation conducted at Shandaweel Agricultural Research Station, Agricultural Research Center, Egypt during two growing seasons 2016/2017 and 2017/2018.

The genetic diversity estimated based on 17 morphological characters as well as 21 microsatellite markers i.e.

SSR markers.

The phenotypic results indicated significant and highly significant differences among the studied cultivars.

Based on the morphological data the principal component analysis (PCA) computed where it revealed that the first principal component (PC1) and the second principal component (PC2), explained 49.31 % of the total variability.

PC1 and PC2 used to construct genotype by trait biplot (GT biplot) to group the cultivars into different groups.

In the same context, the genetic variability estimated using microsatellite markers; the results revealed that high polymorphism information content (PIC) and high marker index (MI) were found.

High variation were found in A and B genomes rather than D genome.

Genetic similarity matrix (Jaccard coefficient) was computed based on the presence and absence of SSR marker bands.

Similarity matrix showed that the highest similarity (0.620) was found between Giza 171 and Giza 168 cultivars and the lowest similarity (0.250) was found between Shandaweel 1 and Misr 3 cultivars.

The dendrogram constructed based on similarity matrix and it clustered the cultivars into three main groups.

The correlation coefficient (Pearson coefficient) between individual characters and markers show strong, positive, and significant correlation between specific markers and particular characters suggesting that each of these specific markers is a candidate linked marker for this particular character to be used in Markers Assisted Selection (MAS).

The similarity among cultivars based on morphological characters showed a narrow range, whereas the similarity among cultivars based on SSR showed a broad range.

The similarity based SSR markers was more accurate and informative than morphological characters basis.

This investigation reveals that SSR markers are well utilized in estimating genetic diversity.