Genetic diversity among melon (Cucumis melo L.) accessions revealed by morphological traits and ISSR markers

The genetic relationships among 48 melon (Cucumis melo L.) genotypes collected from various parts of Azerbaijan were determined by comparing their phenotypic and molecular traits. Eleven agromorphological traits and 10 polymorphic inter-simple sequence repeat (ISSR) primers were used to define the genetic diversity. Principal component analysis grouped the agromorphological traits into the first four axes, describing 78% of the total variations. The highest genetic variation coefficient was found for yield per hectare (20.32%) and for fruit length (17.35%). Calculated heritability for yield was 0.96. The analysis of morphological traits grouped the accessions into four clusters. The 10 ISSR primers yielded 35 polymorphic alleles, representing 85.4% of all the amplified loci. The average genetic diversity index determined was 0.70. The highest and the lowest similarity indexes were equal to 0.97 and 0.36, respectively. The 48 accessions were grouped into 10 clusters based on ISSR markers. Correlation between distance matrices based on agromorphological traits and ISSR markers was not statistically significant (r = 0.012)

Genomic Analysis Confirms Population Structure and Identifies Inter-Lineage Hybrids in Aegilops tauschii

Aegilops tauschii, the D-genome donor of bread wheat, Triticum aestivum, is a storehouse of genetic diversity, and an important resource for future wheat improvement. Genomic and population analysis of 549 Ae. tauschii and 103 wheat accessions was performed by using 13,135 high quality SNPs. Population structure, principal component, and cluster analysis confirmed the differentiation of Ae. tauschii into two lineages; lineage 1 (L1) and lineage 2 (L2), the latter being the wheat D-genome donor. Lineage L1 contributes only 2.7% of the total introgression from Ae. tauschii for a set of United States winter wheat lines, confirming the great amount of untapped genetic diversity in L1. Lineage L2 accessions had overall greater allelic diversity and wheat accessions had the least allelic diversity. Both lineages also showed intra-lineage differentiation with L1 being driven by longitudinal gradient and L2 differentiated by altitude. There has previously been little reported on natural hybridization between L1 and L2. We found nine putative inter-lineage hybrids in the population structure analysis, each containing numerous lineage-specific private alleles from both lineages. One hybrid was confirmed as a recombinant inbred between the two lineages, likely artificially post collection. Of the remaining eight putative hybrids, a group of seven from Georgia carry 713 SNPs with private alleles, which points to the possibility of a novel L1–L2 hybrid lineage. To facilitate the use of Ae. tauschii in wheat improvement, a MiniCore consisting of 29 L1 and 11 L2 accessions, has been developed based on genotypic, phenotypic and geographical data. MiniCore reduces the collection size by over 10-fold and captures 84% of the total allelic diversity in the whole collection

Analysis of genetic diversity among different tomato genotypes using ISSR DNA marker

Inter simple sequence repeat (ISSR) markers were used for variation analysis among 41 tomato accessions. A total of 50 scorable bands were obtained, where 32 were polymorphic, representing 63.3% of all the amplified loci. Polymorphism percentage ranged from 50 to 90% and an average number of polymorphic bands of 4.0 were observed. An average genetic diversity index was 0.61. Primer UBC860 and UBC825 generated the greatest diversity index with a value of 0.89 and 0.85 respectively. The smallest diversity identified by primer UBC808, with an index of 0.34. The genetic similarity among studied genotypes ranged from 0.52 to 0.98. The cluster analysis based on Jaccard’s similarity coefficient divided genotypes into 6 distinct clusters on a value of 0.74. The lowest genetic distance was found between ‘Gronastiy’ and ‘AG1224’ (0.52), ‘Orange’ and ‘AG1224’ (0.54), and ‘Evgeniya’ and ‘AG1224’ (0.55) accessions. The highest similarity of 0.98 was determined between ‘Zafar’ and ‘Azerbaijan-94’, ‘Khachmaz-1’ and ‘Azerbaijan-94’, ‘Khachmaz-1’ and ‘Severyanka’, and ‘Shakar’ and ‘Absheron-1’ accessions

Adaptive reaction of cotton accessions of G. hirsutum L. and G. barbadense L. species to drought stress

Adaptation, process of the adjustment of a plant to specific environmental conditions, is provided by physiological mechanisms (physiological adaptation), and at population level (species) by mechanisms of genetic variability, heredity and selection (genetic adaptation). Intraspecific and the interspecific physiological assessment of adaptation potential to drought stress was carried out on 267 collection accessions and varieties of a cotton (197 accessions of G. hirsutum L. and 70 of G. barbadense L.). Comparative study of the stress reaction of tested accessions to unfavorable environmental factors was carried out based on stress depression indices of viability of seeds in sucrose solution-imitating drought. As a result of the studies different sensitivity of plants to abiotic stress was determined. The amplitude of the changes of physiological parameter during stress allowed roughly divide cotton accessions within each species into groups by defining different degrees of comparative drought resistance of samples. Analysis of the percentage ratio of high drought resistant accessions within species, revealed differences between G. hirsutum L. and G. barbadense L. For the specie G. hirsutum L. percentage of accessions with high drought resistance was 9.1%, for specie G. barbadense L.-28.6%. G. barbadense L., in our view, is characterized by a greater potential for volatility and acclimatization to the new, unusual conditions, capable of better resisting the adverse effects of drought and has great promise for using in breeding. It was found that because of the stress in drought resistant varieties activation of RNA synthesis, increase of labile and decrease of stable DNA was observed which indicates an increase of the physiological liability and functional activity of the genetic apparatus. In susceptible varieties a reduction in the synthesis of RNA and DNA and displacement of DNA fraction ratio towards the stable were noted

Assessment of genetic diversity and search for Plum pox virus resistance alleles of apricot<i> (Prunus</i><i> armeniaca</i> L.) genotypes spread in Azerbaijan using SSR markers

Apricot is one of the most important stone-fruit plants widely cultivated in Azerbaijan. SSR markers were used to evaluate the genetic diversity of 61 apricot genotypes representing the entire gene pool in Azerbaijan. A total of 138 alleles were produced based on 17 SSR markers with an average of 8.1 alleles per primer. The polymorphism information content (PIC) and expected (He) heterozygosity for individual loci were in the range of 0.42-0.8 (mean 0.68) and 0.52-0.82 (mean 0.72), respectively, indicating the abundant genetic variation in Azerbaijani apricot cultivars. The polymorphisms generated by SSRs were enough to differentiate 95% of genotypes, while 4 apricot cultivars exhibited complete similarity between them. NJ tree grouped the 61 genotypes into 7 clusters with 1000 bootstrap values, where the grouping of genotypes was not closely related to the geographic origin or collection site. STRUCTURE analysis identified 4 subpopulations in the collection and, in general, was in agreement with cluster analysis. (SEO)/Harlayne-type resistance alleles of three SSR (PGS1.21-240 bp, PGS1.23-161 bp, PGS1.24-119 bp) and one SSLP loci (ZP002-127 bp) were detected in 3, 15, 15, and 9 accessions, respectively. STRUCTURE analysis could separate genotypes with resistance alleles grouping them in the first two subpopulations. Of the 61 apricot genotypes, 28 had at least one resistance allele. The results demonstrate that Azerbaijani apricots are an important source for breeding PPV-resistant apricots

Genetic diversity of chickpea genotypes as revealed by ISSR and RAPD markers

Genetic diversity of 62 chickpea accessions was studied using 8 ISSR and 11 RAPD primers. In the study RAPD primers detected more polymorphism (98%) than the ISSR primers (80%). Genetic diversity index was high (0.73 for ISSR and 0.85 for RAPD) for each of these marker systems. Cluster analysis performed from both separate and combined data of RAPD and ISSR markers using SPSS software package. Jaccard’s similarity coefficient for 62 chickpea genotypes was 0.65. Cluster analyses based on combined data generated a dendrogram that separated genotypes into 11 clusters. Four clusters contained only one genotype showing the genetic uniqueness of these accessions. The studied chickpea collection has been proved to constitute a rich source of biodiversity as revealed by RAPD and ISSR markers. Crossing between distantly related genotypes is expected to yield more vigorous plants constituting much of the different traits contained in the two parental lines

Genetic relationship among introduced lentil germplasm using agronomic traits and ISSR markers

Lentil (Lens culinaris Medik.) is an annual, cool-season grain legume playing an important role in human and animal nutrition, as soil fertility maintenance. National lentil improvement program in Azerbaijan is currently focused on extending the genetic base of the lentil collection through the introduction of new breeding lines from ICARDA and involving them into breeding. The present study was aimed to evaluate the performance of lentil collection, mainly comprised of ICARDA-derived breeding lines for yield traits under Azerbaijan condition and assess genetic diversity among them using inter simple sequence repeats (ISSR) markers. Many breeding lines of ICARDA exhibited agro-morphological performance superior to those of the local improved varieties. Our studies confirmed that the genetic base of the studied lentil collection is quite above board. A total of 71 bands were generated using 7 ISSR primers in 47 lentil genotypes, of which 62 were polymorphic. Genetic diversity values varied from 0.61 (UBC 848) to 0.95 (UBC 835), with a mean of 0.81. ISSR dendrogram was able to clearly distinguish all lentil accessions. Clear tendention was observed on clustering of genotypes according to their pedigree or origin with few exeptions. The results obtained from the Principal Coordinate Analysis were consistent with the results of cluster analysis, with minor differences. Breeding lines with high agronomic performance and sufficient genetic distance from this study can be used as appropriate parents to get more heterotic recombinants. This will accelerate the creation of new varieties well adapted to eco-geographic condition of Azerbaijan with stable and high yield