Morphological and molecular characterization of garlic (Allium sativum L.) genotypes sampled from Turkey.

Garlic is a vegetable widely used both in food and as a pharmaceutical raw material in the world due to its contents. Although morphological differences are observed in garlic, which is obligatory apomictically propagated, clonal propagation causes narrowing variation, a genetic bottleneck. This situation complicates breeding programs aiming improvements in preferred agronomic characteristics. For this reason, determining the morphological and molecular differences between garlic genotypes originating from Turkey is important for breeding studies. In this study, morphological and molecular characteristics of 39 garlic genotypes, which are widely cultivated in Turkey, were determined. Kahramanmaras4 genotype was different from other genotypes in terms of some morphological features (fresh weight, dry weight, and bulb diameter). In the molecular characterization study, 10 Inter-Simple Sequence Repeats (ISSR) primers were used, and it was determined that the genotype TekDis31 of Tunceli region was different from other garlic genotypes. Genetic similarity coefficient was found to be high (0.85-1.0) in genotypes except for TekDis31 garlic genotype. In general, some garlic clones (Maras3 and Kayseri30, Urfa33 and Topakli35, Kastamonu22 and Kastamonu28, Urfa10 and Kastamonu14, Kastamonu29 and Bademci23) were completely similar to each other, while few differences were found among others. In conclusion, this study revealed that the garlic plant, despite its clonal propagation, consisted of some level of morphological and partially molecular variation. Due to its mode of reproduction (vegetative), this variation may largely be due to point or chromosomal mutation. Furthermore, the 10 identified ISSR primers can generate valuable information for genetic diversity for use by garlic breeders.

Elucidating genetic relationships, diversity and population structure among the Turkish female figs.

A collection of 96 female Turkish fig (Ficus carica L.) accessions was studied to elucidate genetic structure and estimate diversity and genetic similarity distribution among the female figs present in Turkish genetic resources, using 157 molecular genome markers including 129 sequence-related amplified polymorphisms, 21 random amplified polymorphic DNAs, and 7 simple-sequence repeats. The plant samples mainly included Turkish fig collections selected throughout the country over the course of a half-century. Neighbor-joining analysis revealed continuous dissimilarity range, and it was difficult to classify figs into distinct groups. The principle component analysis produced similar results. The analysis of molecular variance indicated that 95 and 93% of genetic variation were explained by within geographic origins and similar fruit rind color, respectively. Sub-structuring Bayesian analysis assigned the 96 female figs into four sub-populations, and indicated that they were highly related. The corrected allelic pairwise distances among the six geographic origins were less than 5%. This study suggests that geography- and color-based groups were not genetically distinct among the Turkish figs.

Polyploidy creates higher diversity among Cynodon accessions as assessed by molecular markers.

Developing a better understanding of associations among ploidy level, geographic distribution, and genetic diversity of Cynodon accessions could be beneficial to bermudagrass breeding programs, and would enhance our understanding of the evolutionary biology of this warm season grass species. This study was initiated to: (1) determine ploidy analysis of Cynodon accessions collected from Turkey, (2) investigate associations between ploidy level and diversity, (3) determine whether geographic and ploidy distribution are related to nuclear genome variation, and (4) correlate among four nuclear molecular marker systems for Cynodon accessions' genetic analyses. One hundred and eighty-two Cynodon accessions collected in Turkey from an area south of the Taurus Mountains along the Mediterranean cost and ten known genotypes were genotyped using sequence related amplified polymorphism (SRAP), peroxidase gene polymorphism (POGP), inter-simple sequence repeat (ISSR), and random amplified polymorphic DNA (RAPD). The diploids, triploids, tetraploids, pentaploids, and hexaploids revealed by flow cytometry had a linear present band frequency of 0.36, 0.47, 0.49, 0.52, and 0.54, respectively. Regression analysis explained that quadratic relationship between ploidy level and band frequency was the most explanatory (r = 0.62, P < 0.001). The AMOVA results indicated that 91 and 94% of the total variation resided within ploidy level and provinces, respectively. The UPGMA analysis suggested that commercial bermudagrass cultivars only one-third of the available genetic variation. SRAP, POGP, ISSR, and RAPD markers differed in detecting relationships among the bermudagrass genotypes and rare alleles, suggesting more efficiency of combinatory analysis of molecular marker systems. Elucidating Cynodon accessions' genetic structure can aid to enhance breeding programs and broaden genetic base of commercial cultivars.

Buffalograss germplasm resistance to Blissus occiduus (Hemiptera: Lygaeidae).

Plant germplasm collections may offer genetic variability useful in identifying insect resistance. The goal of this project was to evaluate buffalograss genotypes [Buchloë dactyloides (Nutt.) Engelm.] for resistance to the chinch bug, Blissus occiduus Barber (Hemiptera: Lygaeidae), and to relate resistance to ploidy level, chinch bug number, and pubescence. Forty-eight buffalograss genotypes from diverse geographic locations were evaluated in replicated studies under greenhouse conditions. Of the genotypes studied, four were highly resistant, 22 were moderately resistant, 19 were moderately susceptible, and three were highly susceptible to chinch bug damage. The mean number of chinch bugs was significantly different among the 48 genotypes. There was no significant correlation between chinch bug resistance and ploidy level or chinch bug resistance and pubescence. These results indicate the genetic source of resistance to chinch bugs exists in buffalograss germplasm. Highly resistant genotypes can be used in breeding programs to further improve buffalograss cultivars.

Elucidating polyploidization of bermudagrasses as assessed by organelle and nuclear DNA markers.

Clarification of relationships among ploidy series of Cynodon accessions could be beneficial to bermudagrass breeding programs, and would enhance our understanding of the evolutionary biology of this warm season grass species. This study was initiated to elucidate polyploidization among Cynodon accessions with different ploidy series collected from Turkey based on chloroplast and nuclear DNA. Forty Cynodon accessions including 7 diploids, 3 triploids, 10 tetraploids, 11 pentaploids, and 9 hexaploids were analyzed using chloroplast DNA restriction fragment-length polymorphism (cpDNA RFLP), chloroplast DNA simple sequence repeat (cpDNA SSR), and nuclear DNA markers based on neighbor-joining (NJ) and principle component analyses (PCA). All three-marker systems with two statistical algorithms clustered the diploids apart from the other ploidy levels. Assuming autopolyploidy, spontaneous polyploidization followed by rapid diversification among the higher ploidy levels than the diploids is likely in Cynodon's evolution. Few tetraploid and hexaploid accessions were clustered with or closely to the group of diploids, supporting the hypothesis above. Eleven haplotypes as estimated by cpDNA RFLP and SSR markers were detected. This study indicated that the diploids had different organelle genome from the rest of the ploidy series and provided valuable insight into relationships among ploidy series of Cynodon accessions based on cp and nuclear DNAs.