Development of Indian mustard [Brassica juncea (L.) Czern.] core collection based on agro-morphological traits

Genetic Resources and Crop Evolution - Indian mustard [Brassica juncea (L.) Czern.] is a major edible oil crop of India. The Indian Council of Agricultural Research—National Bureau of Plant...     

Genetic diversity in sorghum [<Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench] germplasm from Southern Africa as revealed by microsatellite markers and agro-morphological traits

Cultivated sorghum [Sorghum bicolor (L.) Moench] is an important food security crop in the semi-arid regions of the world including Asia and Africa. Its genetic diversity is contained mostly in traditional varieties and modern cultivars used by farmers. In this study, agro-morphological traits and molecular markers were used to assess genetic diversity in 22 accessions of cultivated sorghum from five countries (Botswana, Namibia, Swaziland, Zambia and Zimbabwe) in the Southern African Development Community (SADC) region. The study revealed a significant variation among 22 accessions in both qualitative and quantitative morphological traits, indicating the accessions’ promising potential as breeding material. For molecular analysis, 11 microsatellite primer-pairs were used, and generated a total of 70 alleles across 20 accessions. Analysis of molecular variance revealed a high level of genetic variation; 67 % among the accessions and 10 % among the five countries. The patterns of genetic diversity and the relationships observed in this study should provide insights for genetic resource conservation and utilization of sorghum germplasm in the SADC region.     

Evaluation of genetic diversity in a Camelina sativa (L.) Crantz collection using microsatellite markers and biochemical traits

A genomic DNA library enriched with GA/TC repeats from Camelina sativa variety Calena has been analysed. After sequencing of about 200 randomly selected clones, approximately 60 % of them showed to contain simple or compound microsatellites with a high number of repeats. Among all microsatellite markers analysed 15 primer pairs amplified polymorphic fragments. Forty C. sativa accessions of different origin were genotyped with 15 microsatellite markers that generated 134 alleles with an average of 8.93 alleles per locus. The observed heterozygosity (Ho) among the accessions ranged from 0.0 to 0.15 with an average of 0.0370, whereas the average of expected heterozygosity (He) among accessions was 0.2769. The analysis of the average total heterozygosity (H_T = 0.651), the intrapopulation genetic diversity (H_S = 0.260), the interpopulation genetic diversity (D_ST = 0.391) and the coefficient of genetic differentiation among populations (G_ST = 0.574) demonstrated that 57.4 % of the genetic diversity is among the accessions, while 42.6 % resides within them. Phylogenetic tree of the 40 C. sativa accessions was constructed based on Nei’s genetic distance. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram shows, except for CAM108 and CAM170, a clear discrimination among C. sativa accessions grouping them in five subgroups. ANOVA analysis indicates significant differences in some biochemical and agronomic parameters among the C. sativa accessions grouped according to Nei’s genetic distance. The result of the Tukey HSD test demonstrated that the A4 subgroup showed a significant higher TWS and linoleic acid (LA) content, while the subgroup A1 showed a significant higher linolenic and lower LA content compared to the remaining groups.     

Ecogeographical distribution of wild, weedy and cultivated Sorghum bicolor (L.) Moench in Kenya: implications for conservation and crop-to-wild gene flow

The potential gene flow between a crop and its wild relatives is largely determined by the overlaps in their ecological and geographical distributions. Ecogeographical databases are therefore indispensable tools for the sustainable management of genetic resources. In order to expand our knowledge of Sorghum bicolor distribution in Kenya, we conducted in situ collections of wild, weedy and cultivated sorghum. Qualitative and quantitative morphological traits were measured for each sampled wild sorghum plant. Farmers’ knowledge relating to the management of sorghum varieties and autecology of wild sorghum was also obtained. Cluster analysis supports the existence of several wild sorghum morphotypes that might correspond to at least three of the five ecotypes recognized in Africa. Intermediate forms between wild and cultivated sorghum belonging to the S. bicolor ssp. drummondii are frequently found in predominantly sorghum growing areas. Crop-wild gene flow in sorghum is likely to occur in many agroecosystems of Kenya.     

Evaluation of genetic diversity and relationships within an on-farm collection of Perilla frutescens (L.) Britt. using microsatellite markers

The present study demonstrates utilization of 11 microsatellite markers to explore genetic diversity held in Perilla frutescens (L.) Britt. landrace accessions growing on farms in different parts of Korea and Japan and to assess their genetic relationships. All microsatellite loci were polymorphic and produced a total of 96 alleles ranging from 4 to 20, with an average of 8.7 alleles per locus. Of the 96 alleles found, a total of 15 unique landrace-specific alleles were observed at 9 different loci. The locus GBPFM203 provided the highest number of alleles (20), of which five were unique and each specific to a particular landrace accession. The occurrence of unique, accession-specific alleles presented molecular evidence for the generation of new alleles within on-farm collection of Perilla. The mean values of observed (H _O) and expected heterozygosity (H _E) were 0.39 and 0.68, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped the two Perilla varieties, var. frutescens and var. crispa (Thunb.) Decne into two distinct groups. Accessions belonging to var. frutescens could also be divided into two subgroups at a close genetic distance (GD = 0.432). The overall clustering pattern did not strictly follow the grouping of accessions according to their geographic origins. These observations are indicative of extensive germplasm exchange among farms from different geographical regions. The genetic similarity observed among the Perilla landraces may be useful for future Perilla crop variety identification, conservation, and improvement programs.     

Genetic diversity analysis and character associations in black cumin (Nigella sativa L.) based on agro-morphological and phytochemical traits

Black cumin (Nigella sativa L.) is one of the important medicinal plants that used in food and pharmaceutical industries. In the present study, 32 Iran endemic black cumin genotypes were evaluated through randomized complete block design with three replications in 2016 and 2017 growing seasons to determine the extent of genetic diversity and character associations for agro-morphological and phytochemical traits. Results showed the significant differences between genotypes for all traits studied. Clustering analysis using agro-morphological and phytochemical traits grouped genotypes into the two distinct groups. The values of percentage of essential oil and fatty oil content varied from 0.65 to 0.1.36% and 25.30% to 35.02% between genotypes, respectively. The highest seed yield and fatty oil yield obtained for Arak genotype. GC and GC/MS analyses of essential oil and fatty oil compositions of the Arak genotype revealed that p-cymene and linoleic acid were main components, respectively. Stepwise regression analysis revealed that shoot dry mass, days to ripening and seed length were the most important traits associated with seed yield, fatty oil yield and essential oil yield. Hence, these traits can be considered as important indicators for early selection for seed yield and quality in black cumin breeding programs.     

Population genetic diversity and genetic affinity analyses of sweet orange cultivars (Citrus sinensis (L.) Osbeck) by using IRAP molecular markers

Genetic Resources and Crop Evolution - Citrus plants are one of the most important fruit plants which are consumed all over the world. The breeding of these valuable fruit plants is based on...     

Genetic diversity in wild and cultivated black raspberry (Rubus occidentalis L.) evaluated by simple sequence repeat markers

Breeding progress in black raspberry (Rubus occidentalis L.) has been limited by a lack of genetic diversity in elite germplasm. Black raspberry cultivars have been noted for showing very few phenotypic differences and seedlings from crosses between cultivars for a lack of segregation for important traits. Despite these challenges, little molecular work has been done to explore genetic diversity and relationships in wild and cultivated black raspberry germplasm. Microsatellite, or simple sequence repeat (SSR), markers are highly polymorphic codominant markers useful for studying genetic diversity, population genetics, genetic fingerprinting and other applications. We examined genetic diversity in 148 wild and cultivated black raspberry accessions using 21 polymorphic SSR markers. Black raspberry cultivars clustered tightly and showed higher than expected heterozygosity while that of wild accessions was low. Relationships between wild black raspberry accessions were poorly resolved and regional clusters were mostly absent from our analysis. Our results indicated that wild black raspberry germplasm is a relatively untapped resource available for future breeding.     

Spontaneous gene flow and population structure in wild and cultivated chicory, Cichorium intybus L.

Spontaneous gene flow between wild and cultivated chicory, Cichorium intybus L., may have implications for the genetic structure and evolution of populations and varieties. One aspect of this crop-wild gene flow is the dispersal of transgenes from genetically modified varieties, e.g. gene flow from GM chicory to natural chicory could have unwanted consequences. With the purpose to identify and quantify crop-wild gene flow in chicory, we analysed introgression in 19 wild chicory populations and 16 accessions of chicory varieties and landraces distributed across Northern, Central and Mediterranean Europe. The analysis used 281 AFLP markers and 75 SSAP markers giving a total of 356 polymorphic markers. Results from model based assignments with the program STRUCTURE indicated many incidents of recent gene flow. Gene flow was observed both between cultivars and wild populations, between landraces and wild populations, between different wild populations as well as between cultivars. Population structure visualized by distance-based clustering showed a North–South geographical structuring of the wild populations, and a general grouping of the cultivars corresponding to known origin. The results indicated, however, that the structuring between the two groups of wild and cultivated types was weak. As crop and wild recipients are genetically close and genes are transferred between the two types rather frequently, focus on mitigating crop-wild gene flow should be increased, before transgenic varieties are cultivated openly.     

Population structure and phylogenetic relationship of Peach [Prunus persica (L.) Batsch] and Nectarine [Prunus persica var. nucipersica (L.) C.K. Schneid.] based on retrotransposon markers

For effective varietal improvement of horticultural crops peach (Prunus persica) and nectarine (Prunus persica var. nucipersica), information about their population structure and genetic relatedness plays an important role. In this study we used retrotransposon-based markers (iPBS) to estimate the genetic diversity and population structure of 48 peach and nectarine genotypes from various distinct geographical regions of Punjab and Khyber Pakhtunkhwa, Pakistan. A total of 461 alleles were identified from PCR amplicons derived from nine iPBS primer pairs with an average of 8.5 alleles/locus. Among all four groups the genotypes collected from Swat and Hunza had the highest and the lowest expected heterozygosity, unbiased expected heterozygosity and Shannon’s information index, respectively. We constructed a Neighbour-Joining dendrogram and performed principal coordinate analysis based on the distance matrices, and both forms of analysis grouped the 48 genotypes into two distinct clusters. The STRUCTURE software distributed the forty-eight genotypes into two main populations (k?=?2) indicating a low diversity between genotypes collected from Chakwal, Swat, Mansehra and Hunza.

     

Revealing genetic diversity and population structure in Pistachio (Pistacia vera L.) by SSR markers

Genetic Resources and Crop Evolution - Pistachio (Pistacia vera L.) is the only cultivated species in Pistacia genus and it is one of the most important species of hard-shelled fruits. Pistachio...     

Development and characterization of microsatellite markers,genetic diversity and population structure analysis in Sapota (Manilkara zapota (L.) P. Royen)

Genetic Resources and Crop Evolution - Manilkara zapota (L.) P. Royen, a widely adapted and popular tree meant for its appetizing fruits in tropics with no genomic resources like microsatellite...     

Genetic diversity and population structure in Jatropha (Jatropha curcas L.) based on molecular markers

Genetic Resources and Crop Evolution - Jatropha (Jatropha curcas L.) is an oleaginous potential, howetever, some studies report that there is low genetic diversity in Brazilian genotypes....     

Genetic diversity of cultivated flax (Linum usitatissimum L.) and its wild progenitor pale flax (Linum bienne Mill.) as revealed by ISSR markers

Little is known about the genetic diversity of pale flax (Linum bienne Mill.), the wild progenitor of cultivated flax (L. usitatissimum L.), and ex situ germplasm of pale flax was scarce. Effort was made to collect 34 pale flax accessions and five landrace accessions of cultivated flax in Turkey. The inter simple sequence repeat (ISSR) technique was applied to characterize this set of flax germplasm, along with one Turkish cultivar, one Russian cultivar, five winter and four dehiscent type accessions of cultivated flax. Twenty-four ISSR primer pairs detected a total of 311 DNA fragments, of which 298 bands were polymorphic across 493 flax samples (roughly 10 samples per accession). These polymorphic bands had frequencies ranging from 0.002 to 0.998 and averaging 0.38. Accession-specific ISSR variation (Fst values) ranged from 0.469 to 0.514 and averaged 0.493. There was 49.3% ISSR variation resided among these 50 accessions, 35.9% harbored among landrace, winter, dehiscent types of cultivated flax and pale flax, and 38.2% present among 34 pale flax accessions. Pale flax displayed more ISSR variation than landraces and dehiscent type, but less than winter type, of cultivated flax. Clustering 493 individual plants revealed that these assayed plants were largely grouped according to their plant types and that pale flax was genetically more close to the dehiscent type, followed by the winter type and landrace, of cultivated flax. Pale flax collected within the geographic range of 180 km displayed a significant spatial genetic autocorrelation. Genetic distances among the pale flax accessions were significantly associated with their geographic distances and elevation differences. These findings are significant for understanding flax domestication and its primary gene pool.     

Assessment of phenotypic and molecular diversity in soybean [Glycine max (L.) Merr.] germplasm using morpho-biochemical attributes and SSR markers

Genetic Resources and Crop Evolution - Soybean is a high-nutritional crop that provides a sustainable source of dietary protein and edible oil for human consumption and animal diet. In this...     

Analysis of genetic diversity and population structure of 135 dill (Anethum graveolens L.) accessions using RAPD markers

Dill (Anethum graveolens L.) leaf, seed and their essential oil are rich source of antioxidants. The plant is native in Southwest Asia and is cultivated in Europe, India and the United States. This study evaluated the genetic diversity structure of 135 accessions of A. graveolens from different continents, based on random amplified polymorphic DNA (RAPD) markers. The selected 10 RAPD primers generated a total of 142 highly reproducible bands, among which 89 were polymorphic. Percentage of polymorphism varied from 41.17 % (OPB20) to 92.85 % (OPB15) with an average of 77.74 %. A relatively high genetic diversity was detected among all the accessions with the Nei’s genetic diversity (H) values ranged from 0.346 (OPB07) to 0.444 (OPB18) with a mean of 0.401. When estimated for Shannon’s information index (I), it has ranged from 0.530 (OPB12) to 0.652 (OPB18), the mean was observed as 0.581. The respective values of H and I were found to be the highest value for primer OPB18. Cluster analysis of RAPD data using UPGMA algorithm based on Nei’s genetic similarity matrix placed the 135 accessions into two main clusters. Although a number of groups can be identified, the clusters show little to no association with the geographic origin of the material. The implication of the results of this study in developing a strategy for the conservation and breeding of dill germplasm are discussed.     

Seed longevity studies in wild type,cultivated and inter-specific recombinant inbred lines (RILs) of soybean [Glycine max (L.) Merr.]

Genetic Resources and Crop Evolution - Loss of seed viability is a serious hurdle in production and ambient seed storage of soybean. Understanding the factors affecting seed viability,&nbsp;and...