The world collection of pearl millet at ICRISAT genebank includes 19,696 landraces. Passport and characterization data of 2,929 accessions belonging to 89 named landraces originating in 15 countries of Africa was used to study the adoption pattern and genetic potential. Out of 89 named landraces under study, 71 were grown in one country, 11 in two countries, six in three countries and one in four countries. Latitude and prevailing climate at collection sites were found as the important determinants of cultivation pattern of landraces. A hierarchical cluster analysis using 12 agronomic traits resulted in five clusters. Cluster 1 for late flowering, short height in rainy season, high tillering and thin panicles; cluster 2 for early flowering; cluster 3 for stout panicles in both the seasons and larger seeds and cluster 5 for longer panicles in both seasons, were found as promising sources. IP 8957, IP 8958, IP 8964 of Iniadi landrace for short height, downy mildew and rust resistance and high seed iron and zinc contents; IP 17521 of Gnali (106.9 ppm) and IP 11523 of Idiyouwe (106.5 ppm) for high seed iron content; IP 17518 of Gnali (79.1 ppm) and IP 11535 of Iniadi (78.4 ppm) for high seed zinc content were the important sources. All accessions of Raa for high seed protein content (>15%) and those of Enele for drought tolerance, were found to be promising sources. Further evaluation of promising sources identified in this study is needed for enhanced utilization of germplasm in pearl millet improvement.

Only a little information is available on the genetic association of basic within-boll yield components of segregating populations. A total of 25 genotypes were evaluated for genetic diversity using SSR markers in 2012; of these, eight diverse genotypes were selected to attempt the generation of five crosses. From the progeny of these five crosses, five F3 populations were developed. Data for within-boll yield components were recorded by taking 30 observations (one observation average of five bolls) from each population, and analysed for genotypic and phenotypic correlations followed by the path coefficient analysis from the genotypic correlation. The highest genotypic correlation was observed between seed cotton yield per locule and number of seeds per boll (ranging from 0.654 to 0.972 for different crosses). Except number of seeds per locule and lint percentage, all the other within-boll yield components had a highly significant positive correlation with seed cotton yield, whereas the former two had a negative correlation. Path coefficient analysis revealed that number of seeds per boll had a maximum direct effect on yield (ranging from 0.776 to 0.895 for different crosses), and also had a relatively high magnitude of the indirect effect via other traits. Differences were observed in the magnitude of correlation coefficients and direct/indirect effects for different populations, but the direction of genetic association always remained the same. The present study showed that number of locules per boll, seed cotton yield per locule, number of seeds per boll and seed cotton yield per boll can be used as efficient selection criteria for the improvement in seed cotton yield.

Fungal blast disease is one of the major constraints in finger millet production. Breeding for disease resistance in finger millet, needs characterization of genetic polymorphism among and between the resistant and susceptible genotypes. In total, 67 finger millet genotypes, which are resistant or susceptible to fungal blast disease, were analysed using sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers to assess genetic variations and select diverse parents. Twelve each of SRAP and SSR primers produced 95.1 and 93.1% polymorphic bands and grouped them into unweighted pair-group method with arithmetic average clusters. Two of the finger millet genotypes, IE 4709 (blast resistant) and INDAF 7 (susceptible) were distinguished as most diverse genotypes as parents. Several genotype-specific bands observed with SSR primers are potential in developing genotype-specific markers. A high genetic diversity within the resistant and susceptible genotypes, rather than between them, was revealed through Nei's gene diversity (h) index and analysis of molecular variance. The finding helps us to understand the extent of genetic polymorphism between blast disease resistant and susceptible finger millet genotypes to exploit in resistance breeding programs.

The wild species of tomato Solanum pennellii (Lpa) is more tolerant to salt-induced oxidative stress than the cultivated species Solanum lycopersicum (Lem), due to the increase of several antioxidative metabolites and enzymes in this species under stress. The increase of reduced glutathione (GSH), one of these metabolites, in NaCl-treated Lpa, is due at least partly to the elevation of γ-glutamylcysteine synthetase (γ-ECS). Introgression line IL 8–3, which was found to include the Lpa orthologue of the γ-ECS gene (Lpa γ-ECS) in Lem's genetic background, was used to assign this gene to chromosome 8 and to assess its relative contribution to the effective antioxidative response of Lpa to stress. The growth of IL 8–3 and Lem plants responded similarly to NaCl and cadmium (Cd) stresses. In both genotypes, GSH and H2O2 levels responded also similarly to NaCl stress. NaCl and Cd stresses affected similarly the transcription of the γ-ECS gene in leaves of both IL 8–3 and Lpa plants. The effect of buthionine sulfoximine (BSO), a competitive inhibitor of the γ-ECS enzyme, on γ-ECS transcription was also similar in these two genotypes. Taken together, these results suggest that γ-ECS orthologues differ mainly in the regulation of their transcription and not at the post-transcriptional or translational levels. The mutation(s) led to these differences in the response of the two orthologues to the salinity and heavy metal stresses are expected to occur in a cis-regulatory element(s) located relatively close to γ-ECS.

This study assessed the genetic diversity in 928 individuals from 40 diploid populations of Lolium perenne using nuclear simple sequence repeat markers, including 22 accessions of Irish ecotypes, seven European ecotypes and 11 released varieties. High levels of allelic and genetic diversity were determined, with intra-population variation accounting for the majority of the variation. The majority of the accessions deviated from Hardy–Weinberg equilibrium and had relatively high inbreeding coefficients. Two major gene pools of ecotypic accessions were defined by unweighted pair group method with arithmetic mean (UPGMA) and PCA analyses. One of these two gene pools accounted for two-thirds of the ecotypes and included most of the current Irish and Northern Irish breeding materials and about half of the European ecotypes included in this study; these European ecotypes performed well under Irish selection conditions. Population structure and differentiation analyses using Structure analysis and analysis of molecular variance confirmed the results found in the UPGMA and PCA analyses. These results will be useful for breeders who wish to exploit specific pools from ecotype collections.

The genetic diversity of 39 Iranian black cumin (Nigella sativa L.) landraces was analysed using 14 polymorphic Start Codon Targeted (SCoT) markers. A total of 106 bands ranging from 3 (for SCoT70) to 13 (for SCoT23) were observed. Of them, 33 (31%) bands were polymorphic with a mean of 1.65 bands per primer. Polymorphism information content (PIC) per primer ranged from 0.035 (for SCoT12) to 0.133 (for SCoT70), with an average of 0.078. Besides PIC, Simpson's diversity (D) index was also calculated for each SCoT marker as an indication of discrimination power across population. The D index was used to adjust the PIC of the SCoT markers. As the adjusted PIC (PICD= PIC × D) was calculated based on both the PIC and the rate of band dispersion, this reflected the informativeness of a dominant marker more precisely than PIC. Genetic relationships were estimated using Jaccard's similarity coefficient-generated values between different pairs of genotypes that varied from 80 to 97% with an average of 88%. These coefficients were applied to construct a dendrogram using the UPGMA algorithm. A high genetic similarity was observed that might be due to the fact that N. sativa is a self-pollinated plant not originated from Iran and might have been imported from the Mediterranean regions.

Landraces are an important resource for crop breeding, due to their resilience and content of quality traits. However, genetic and phenotypic variability needs to be carefully characterized for proper direct and indirect use. In the present study, a multidisciplinary approach was carried out to assess the Italian sweet pepper landrace ‘Friariello’. A total of 18 traditional accessions were compared with five hybrids and two ecotypes with similar fruit typology. Genetic and morpho-agronomic characterization allowed us to distinguish five different group types of ‘Friariello’. Accessions showing two/three lobes at the blossom end of the fruit were found to be the most productive, whereas the genotypes showing one/two lobes at the blossom end were the most homogeneous. A total of 167 volatile organic compounds (VOCs) were identified in the collection analysed. Moreover, of the 37 targeted VOCs, 29 showed significant differences in content among the pepper genotypes studied. Of such VOCs related to main flavours described for pepper in the literature, ten were found to be the major determinants of variability among the derived ‘Friariello’ groups. A slightly negative, albeit not significant, correlation was observed between ascorbic acid (AsA) content and agronomic traits, suggesting a better quality for less productive accessions, but also the possibility to improve yield without significantly reducing the AsA levels. The approach used allowed us to define how the different typologies can be used for different breeding purposes, integrating the peculiar properties in order to establish a desirable landrace ideotype. Furthermore, valuable sources for improving quality traits in pepper breeding were identified.

Introduction of clones from genetic groups that are underrepresented in the pedigree of commercial cacao varieties in West Africa represents an important aspect of cacao improvement strategy of broadening the genetic base to overcome current yield stagnation of the crop. The objective of the present study was to determine the combining abilities of more recently introduced cacao clones for yield and cropping efficiency in the early bearing years. Seven recently introduced clones were crossed as males to five clones commonly used in the seed gardens in Ghana using a North Carolina II design. The 35 F1 varieties and one commercial variety were evaluated in the field from June 2010 to March 2015 for four traits: increase in trunk cross-sectional area in the juvenile, and in the pod-bearing phases, bean yield and cropping efficiency. Though both GCA and SCA variances were significant for all traits, the ratios of GCA:SCA were much smaller than unity, indicating the importance of non-additive effects in the control of the traits. Among the set of clones therefore, prediction of F1 variety performance cannot be based on the GCA or per se (average) performance of the clones. Six varieties were more precocious, and eight had higher cropping efficiencies than the standard variety. Bean yields ranged from 0.74 to 1.05 t/ha/year in the fourth and fifth years after planting among the top six varieties. The study provides evidence of the large potential for productivity increase through the use of cacao clones beyond Pound's early introductions into West Africa.

Salvia (sage) is the most important and largest genus of the Lamiaceae family. High similarities among species in this genus lead to difficulty in its systematic identification. Despite its economic importance, limited molecular studies have been conducted to evaluate the genetic diversity among and within Salvia species. In this study, SRAP (sequence-related amplified polymorphism) markers, which targeted ORFs (open reading frames) as functional regions in the genome, were used to detect the genetic diversity of five Salvia species (S. virgata Jacq., S. nemorosa L., S. officinalis L., S. cereal L. and S. sclarea L.). Fourteen primer combinations (PCs) were amplified by 265 fragments on 54 genotypes, in which 255 (96%) were polymorphic. The average polymorphism information content (PIC) value was 0.308 over all PCs. The genetic distance among species ranged from 0.126 (between S. virgata Jacq. and S. nemorosa L.) to 0.568 (between S. nemorosa L. and S. sclarea L.). Based on Jaccard's similarity coefficient and UPGMA algorithm, cluster analysis separated different species (r= 0.920). The results showed high genetic differentiation (Fst= 0.337) and negligible gene flow (Nm= 0.750) among species. Owing to the high genetic variation among and within Salvia species, it serves as a rich source of germplasm with potential for use in breeding programmes.

Choclero is a Chilean traditional floury maize, consumed as a vegetable, with large economic and cultural value due to its culinary properties that give unique characteristics to the traditional local cuisine. Market diversification demands new materials with different ear and kernel characteristics, which are at present not fulfilled by breeders due to lack of genetic diversity. At present, the Instituto de Investigaciones Agropecuarias has a Choclero germplasm collection composed of 96 accessions, which can supply this lack of diversity, or increase the gene pool. In the present study, 34 selected Chilean Choclero landraces were characterized for 41 agromorphological traits. Phenotypic evaluation in three environments representative of the core production area revealed significant genetic variability for most of the evaluated traits, leading to the identification of several promising accessions. The greater contribution of genotype in most phenological plant, ear and kernel traits suggest their potential usefulness for breeding purposes. Principal component analysis explained over 75% of the total variation for 29 quantitative agromorphological traits. Cluster analysis separated accessions into four major groups, differentiated mainly by plant phenology and ear trait. These findings indicate a number of useful traits at an intra-racial level and a wide range of phenotypic variation that provides a good source of diversity for use in the development of new Choclero varieties.

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major biotic constraint of rice production in all the major irrigated/lowland rice growing regions of Asia, including Punjab and its adjoining states in India. None of the individual BB resistant Xa/xa genes is effective against Punjab pathotypes. In the present study, we have screened 1176 accessions, comprising 1007 accessions of A genome species Oryza glaberrima, O. barthii, O. nivara, O. rufipogon, O. longistaminata, O. meridionalis, O. glumaepatula and 169 accessions from ten other wild species having CC, FF, EE, BBCC and CCDD genomes against two most recently evolved Xoo pathotypes viz. PbXo-10 and PbXo-8 in Punjab state of India, for two constitutive years 2014 and 2015. Based on 2 years of data, four accessions of O. glaberrima (IRGC102206, IRGC1022445, IRGC102512 and IRGC102520) and two of the O. longistaminata accessions (IRGC92624 and IRGC101754) were identified with immune reaction against PbXo-8. For PbXo-10, O. longistaminata showed large number of accessions with complete to partial resistance followed by O. rufipogon (8), O. nivara (2), O. punctata (2) and O. officinalis (1). Two of the O. longistaminata accessions IRGC92624 and IRGC92644 from Mali were found to have resistance against both the Xoo pathotypes indicating presence of BB resistance gene other than Xa21. These can be transferred to elite cultivars of O. sativa for better management of BB.

The study of unknown and therefore unexploited genetic material from landraces and wild relatives could be essential to help modern plant breeders to respond to ongoing requirements and new challenges in food production. The present study evaluates the most relevant physicochemical values and nutrient contents of a genetically unique array of traditional melon varieties, cultivated in Spain at least since the 19th century, and compares them with modern melon hybrids available on the market. This research is complemented with an assessment of variety, environment and repetition effects on each trait to determine their stability. Spanish melon landraces displayed extraordinary diversity with respect to juiciness (70.59–95.97 g/100 g water fresh weight), firmness (20.75–149.89 N), soluble solids content (9.57–16.53 °Brix), pH (5.04–6.38), total sugars (360.21–877.36 mg/g dry weight), carotenoids (0.01–2.05 μg/g fresh weight) and ascorbic acid values (7.55–44.33 mg/100 g fresh weight). A subset of these landraces, belonging to Piel de Sapo and Rochet market classes, revealed remarkably superior values of ascorbic acid in comparison with all commercial varieties, doubling ascorbic acid values with respect to their corresponding market class. Furthermore, most of these landraces exhibited high acidity and accumulated high levels of sugars, fulfilling those sensory and physicochemical characteristics that researchers and breeders have spent many years seeking. The possibilities of these landraces to be used in improvement projects are innumerable; they should be surely taken into account in the near future.

Potato (Solanum tuberosum L.) has been cultivated in Latvia since the 17th century, and formal breeding programmes have been established since the start of the 20th century. The Latvian potato genetic resource collection consists of 83 accessions of Latvian origin, including landraces, old cultivars released starting from the 1930's, modern cultivars and breeding material. These are maintained in field and in vitro collections. Pedigree information about the potato cultivars is often limited, and the use of hybrids of local cultivars as parents is common in the Latvian potato breeding programme. Ninety-four Latvian potato varieties and breeding lines and some commonly used foreign accessions were genotyped with the potato DNA diversity array technology. Analysis of the Latvian potato genetic resources collection revealed that the amount of genetic diversity has increased in the modern cultivars in comparison with the old cultivars.

In a germplasm bank collection the conservation and characterization of genetic resources is a prerequisite in order to use the material in breeding projects aiming the creation of new cultivars. In the present study, 54 Prunus salicina domestica and Prunus domestica genotypes (including seven Greek cultivars), maintained in the ex situ National Genebank Collection of Greece, were classified using microsatellite (simple sequence repeat, SSR) markers on high resolution melting (HRM) analysis. The SSR primer pairs were chosen from the published literature as originally designed on Prunus species. This combined approach was used to genotype all plum accessions of the collection highlighting the benefits of either method (HRM and SSRs) for cultivar identification. Dendrograms for P. domestica and P. salicina and a combined one with all the genotypes assayed were produced. A total of 15 from the 19 P. domestica accessions analysed, including all the Greek accessions but ‘Avgati Skopelou’, were grouped into the same clade in the combined dendrogram, whereas the remaining four were dispersed into the P. salinica clades. Bayesian structure analysis confirmed that ‘Avgati Skopelou’ differs from the rest of the Greek plum cultivars since it was not grouped into the same cluster. The combination of HRM and SSRs, provided a considerably faster, cost-effective, closed-tube microsatellite genotyping method for molecular characterization of plum cultivars.

Water deficit is an environmental factor that constrains crops to express their ecophysiological potential and causes crop yield reduction. Eruca vesicaria has been reported to be one of the most drought-tolerant species in Cruciferae. In this study, polyethylene glycol-simulated drought tolerance was evaluated in one line of Brassica carinata, one line of Brassica napus and 249 Eruca lines based on the principal component analysis (PCA) and unweighted pair-group arithmetic average (UPGMA) cluster analysis. The PCA based on eight drought tolerance indices indicated that the first three components accounted for 85.46% of the total variation, with principal component (PC) 1 accounting for 43.89%, PC2 for 27.85% and PC3 for 13.73% of the total variation. The UPGMA cluster analysis indicated that B. napus cultivar Zhongshuang 9 and Eruca lines could be clustered into five major groups, with group 1 being, in general, drought sensitive, group 2 being slightly–medium drought tolerant, group 3 being drought tolerant, group 4 being highly drought sensitive and group 5 being highly drought tolerant. B. carinata cultivar XB1, as an outstander, showed high drought sensitivity. The UPGMA cluster dendrogram provides a good representation of the similarity matrix (r= 0.68). The drought-tolerant Eruca materials obtained in this study will be valuable for genetic improvement not only in Eruca itself, but also in Brassica crops since they are drought-tolerant lines from a drought-tolerant species.

Genetic diversity of a red clover global collection was assessed using 36 simple sequence repeat (SSR) primers representing all seven linkage groups (LGs). The number of fragments amplified ranged from 1 to 6 for all the primers. Primer RCS0060 detected highest number of fragments, whereas four SSRs viz., RCS0899, RCS1594, TPSSR40 and RCS6927 amplified single fragment. Size range of amplicons generated by all the primers varied from 100 to 400 bp. Polymorphism information content values ranged from 0.301 to 0.719 with an average value of 0.605. LG wise diversity analysis showed that LG 3 was most diverse (I = 0.65, Ht = 0.44), whereas LG-1 showed minimum diversity (I = 0.48, Ht = 0.26) for the microsatellites used. Bayesian model-based clustering inferred three genetically distinct populations in the red clover germplasm holding and showed considerable admixture in individuals within clusters. Neighbour-joining analysis showed intermixing of accessions within groups. Principal component analysis plot complemented the clustering shown by Structure and distinguished three populations to greater extent. Analysis of molecular variance showed that 91% of the genetic variation was residing within populations, while 9% variation was among populations. Overall, the results showed that a high level of genetic diversity is prevailing in this worldwide collection of red clover, which can be exploited for its genetic improvement through breeding approaches.

Picrorhiza kurroa (family Scrophulariaceae) is a high value medicinal herb used in herbal drug formulations like picroliv, picrolax, etc. It has been collected recklessly from its natural habitat posing endangered status for its existence, thereby necessitating characterization of genetic diversity for its sustainable utilization and conservation. In this study, picrosides content and genetic profiles of 26 accessions of P. kurroa from different locations in north-western Himalayas have been analysed. Picroside-I (P-I) content ranged from 0.37 to 2.7% in fresh shoots whereas total picrosides content (P-I+P-II) ranged from 3.7 to 10.9% in dry rhizomes. High picrosides content accession PKS-1 was identified, both for shoots and rhizomes. To study genetic diversity and correlate picrosides content with their genetic factors, genetic profiling was done using simple sequence repeats (SSRs) identified from P. kurroa transcriptomes. Out of 361 SSR primers tested on 26 accessions, 35 primers yielded polymorphic profiles. Overall low genetic diversity was observed in P. kurroa accessions. The highest polymorphism information content (PIC) of 0.55 was given by SSR marker PKSTS-P9 (TGGTG)4. Mean allele number was 2.97. Mean observed and expected heterozygosities were 0.597 and 0.452, respectively. Among all accessions Nei's genetic diversity (H) was 0.39 and Shannon's information index (I) was 0.58. Cluster analysis of STRUCTURE was comparable to DARWIN. Microsatellite markers would be helpful in the development of DNA diagnostics for the authentication of quality plant material as well as planning a genetic improvement strategy.

Mentha (Nepetoideae, Lamiaceae) is a taxonomically complex genus consisting of 29 species and 11 different hybrids including a number of economically important species among them medical plants used for more than 250 years. Because of its high incidence of polyploidy, diverse morphology, high degree of chromosome number variations and interspecies hybridization, Mentha is considered to be a taxonomical challenge. In this paper, we describe cloning and sequencing of internal transcribed spacers (ITS) 1 and 2 of three mint species: Mentha aquatic L., Mentha longifolia L. (Huds) and Mentha piperita L., collected from natural habitats of Bulgaria. The applicability of ITS1 and ITS2 for molecular fingerprinting and further comparative studies, including the newly obtained ITS1 and ITS2 sequences, was tested in phylogenetic analysis of all eight Mentha species, found in Bulgarian flora.

Chickpea (Cicer arietinum L.) is an important food legume crop grown mostly in Asia and Africa as well as in other parts of the world, and serves as an important source of protein in the diets of vegetarian people. Lot of variation in grain quality traits has been observed in cultivated chickpea in both desi and Kabuli types. It has often been observed that seeds with smaller size have more protein when compared with those with larger size. The joint dependence of these two traits on the same primary characteristics results in this negative relationship. This negative correlation coupled with breeding efforts aimed at increasing grain yield has hampered the progress of improving these two traits simultaneously. Therefore, a germplasm exhibiting wider variability for these quantitative traits is an important resource for the identification of novel alleles. Herein, we report the wide variation observed for five important quantitative traits including days to flowering, days to maturity, plant height, 100-seed weight and protein content, and also report the significant positive correlation observed between 100-seed weight and protein content in a diverse collection of chickpea germplasm comprising both desi and Kabuli types.

Thymus is a widely distributed genus in the Mediterranean region with several species endemic to the Iberian Peninsula. The genetic relationships among the 12 major Thymus taxa, T. albicans, T. caespititius, T. camphoratus, T. capitellatus, T. carnosus, T.lotocephalus, T. mastichina L. ssp. mastichina, T. pulegioides, T. villosus ssp. lusitanicus, T. villosus ssp. villosus, T. zygis ssp. sylvestris and T. zygis ssp. zygis, which occur in Portugal were assessed by AFLP (Amplified Fragment Length Polymorphisms) markers. A general agreement was found between the genetic relationships estimated by the AFLP markers and the accepted Thymus taxonomy based on morphological traits and essential oil content. The AFLP markers also supported suggestions for refinement of the taxonomy of this genus.