Morphological and molecular characterization using ISSR-PCR markers for half diallel crossing for five genotypes of flax.

A field experiment was carried out during the winter seasons 2019 and 2020, using five genotypes of flax (Sakha1, Sakha 3, Sakha 4, Sakha 5, and Sakha 6), which were entered into a half diallel crossing program, in the research station of the College of Agriculture, University of Anbar, within latitude 33.44, longitude 43.39, and height 53 m above sea level, the behavior of these genotypes and their diallel hybrids was evaluated according to the second Griffing method (the first model), with the aim of obtaining one or more single hybrid of flax genotypes (Linum usitatissimum L.), the comparison experiment was applied using the randomized complete block design with three replications to estimate the general and specific combining ability and some genetic parameters as well as the determine the genetic fingerprint of genotypes and their hybrids. The parental genotypes and their diallel hybrids differed significantly in all the studied traits, the hybrids (Sakha 1 x Sakha 6), (Sakha 1 x Sakha 3) and (Sakha 5 x Sakha 6) outperformed and gave a result of (15.92, 14.41 and 14.34 grams) respectively. The results also showed a significant effect of the general and specific combining ability to most of the studied traits, and the ratio of (σ^2 gca/σ^2 sca) was less than one for all the studied traits, the mean degree of dominance is more than the one, and the percentage of heritability in the broad sense was high for all The traits were medium for heritability in the narrow sense for most of the traits except for the trait of seed yield. ISSR markers were used to assess the genetic divergence between 5 flax genotypes and their diallel-hybrids. All eleven primers given 133 bands at a rate of 11.08 bands per primer, the number of divergent segments ranged between 15 for the UBC 835 primer and 9 for the UBC748 and UBC730 primers, with a molecular weight ranging between 350-2200 bp. Total and percentage of differential segments were 110 and 82.70%, respectively. The highest percentage of differentiated fragments was 100% for UBC 852 and UBC 860 primers, depending on binary data, genetic similarity, and the linkage scheme, the genotypes and hybrids were separated into major and minor groups. The analysis of the groups under the comparison ratio between the genotypes and hybrids within the linkage diagram showed that Sakha 5 with 6 Sakha and Sakha 1 with 6 Sakha gave the highest genetic dimension and reached 0.89 and 0.86 respectively, This may be reflected on the hybrids in the field. The results indicated that the ISSR markers were highly efficient in diagnosing the purity and genetic divergence between flax genotypes and their hybrids. Therefore, it is possible to select the components of the result efficiently at the beginning of the second generation and the following generations. [ABSTRACT FROM AUTHOR]