Genetic Diversity in Crop Improvement: The Soybean Experience

2005 ◽  
pp. 119-160
Keyword(s):  
Genetic Diversity ◽  
Crop Improvement

scholarly journals Genetic Diversity of Landraces and Improved Varieties of Rice (Oryza sativa L.) in Taiwan

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ai-ling Hour ◽  
Wei-hsun Hsieh ◽  
Su-huang Chang ◽  
Yong-pei Wu ◽  
Han-shiuan Chin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Indigenous Peoples ◽  
Oryza Sativa L ◽  
Crop Improvement ◽  
Genetic Erosion ◽  
Germplasm Conservation ◽  
Gene Pools ◽  
Improved Varieties ◽  
Breeding Goals

Abstract Background Rice, the most important crop in Asia, has been cultivated in Taiwan for more than 5000 years. The landraces preserved by indigenous peoples and brought by immigrants from China hundreds of years ago exhibit large variation in morphology, implying that they comprise rich genetic resources. Breeding goals according to the preferences of farmers, consumers and government policies also alter gene pools and genetic diversity of improved varieties. To unveil how genetic diversity is affected by natural, farmers’, and breeders’ selections is crucial for germplasm conservation and crop improvement. Results A diversity panel of 148 rice accessions, including 47 cultivars and 59 landraces from Taiwan and 42 accessions from other countries, were genotyped by using 75 molecular markers that revealed an average of 12.7 alleles per locus with mean polymorphism information content of 0.72. These accessions could be grouped into five subpopulations corresponding to wild rice, japonica landraces, indica landraces, indica cultivars, and japonica cultivars. The genetic diversity within subpopulations was: wild rices > landraces > cultivars; and indica rice > japonica rice. Despite having less variation among cultivars, japonica landraces had greater genetic variation than indica landraces because the majority of Taiwanese japonica landraces preserved by indigenous peoples were classified as tropical japonica. Two major clusters of indica landraces were formed by phylogenetic analysis, in accordance with immigration from two origins. Genetic erosion had occurred in later japonica varieties due to a narrow selection of germplasm being incorporated into breeding programs for premium grain quality. Genetic differentiation between early and late cultivars was significant in japonica (FST = 0.3751) but not in indica (FST = 0.0045), indicating effects of different breeding goals on modern germplasm. Indigenous landraces with unique intermediate and admixed genetic backgrounds were untapped, representing valuable resources for rice breeding. Conclusions The genetic diversity of improved rice varieties has been substantially shaped by breeding goals, leading to differentiation between indica and japonica cultivars. Taiwanese landraces with different origins possess various and unique genetic backgrounds. Taiwanese rice germplasm provides diverse genetic variation for association mapping to unveil useful genes and is a precious genetic reservoir for rice improvement.

scholarly journals Genetic Diversity and Population Structure of Serbian Barley (Hordeum vulgare L.) Collection during a 40-Year Long Breeding Period

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Ljiljana Brbaklić ◽  
Dragana Trkulja ◽  
Sanja Mikić ◽  
Milan Mirosavljević ◽  
Vojislava Momčilović ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Hordeum Vulgare ◽  
Crop Improvement ◽  
Genetic Erosion ◽  
Breeding Period ◽  
Phenotypic Variance ◽  
Hordeum Vulgare L ◽  
Phenotypic Data ◽  
Breeding Material

Determination of genetic diversity and population structure of breeding material is an important prerequisite for discovering novel and valuable alleles aimed at crop improvement. This study’s main objective was to characterize genetic diversity and population structure of a collection representing a 40-year long historical period of barley (Hordeum vulgare L.) breeding, using microsatellites, pedigree, and phenotypic data. The set of 90 barley genotypes was phenotyped during three growing seasons and genotyped with 338 polymorphic alleles. The indicators of genetic diversity showed differentiation changes throughout the breeding periods. The population structure discriminated the breeding material into three distinctive groups. The principal coordinate analysis grouped the genotypes according to their growth habit and row type. An analysis of phenotypic variance (ANOVA) showed that almost all investigated traits varied significantly between row types, seasons, and breeding periods. A positive effect on yield progress during the 40-year long breeding period could be partly attributed to breeding for shorter plants, which reduced lodging and thus provided higher yield stability. The breeding material revealed a considerable diversity level based on microsatellite and phenotypic data without a tendency of genetic erosion throughout the breeding history and implied dynamic changes in genetic backgrounds, providing a great gene pool suitable for further barley improvement.

scholarly journals Molecular diversity analysis in hexaploid wheat (Triticum aestivum L.) and two Aegilops species (Aegilops crassa and Aegilops cylindrica) using CBDP and SCoT markers

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ghazal Ghobadi ◽  
Alireza Etminan ◽  
Ali Mehras Mehrabi ◽  
Lia Shooshtari
Keyword(s):  
Genetic Diversity ◽  
Triticum Aestivum ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Crop Improvement ◽  
Wild Relatives ◽  
Resolving Power ◽  
Start Codon ◽  
Aegilops Cylindrica ◽  
Aegilops Crassa

Abstract Background Evaluation of genetic diversity and relationships among crop wild relatives is an important task in crop improvement. The main objective of the current study was to estimate molecular variability within the set of 91 samples from Triticum aestivum, Aegilops cylindrica, and Aegilops crassa species using 30 CAAT box–derived polymorphism (CBDP) and start codon targeted (SCoT) markers. Results Fifteen SCoT and Fifteen CBDP primers produced 262 and 298 fragments which all of them were polymorphic, respectively. The number of polymorphic bands (NPB), polymorphic information content (PIC), resolving power (Rp), and marker index (MI) for SCoT primers ranged from 14 to 23, 0.31 to 0.39, 2.55 to 7.49, and 7.56 to 14.46 with an average of 17.47, 0.34, 10.44, and 5.69, respectively, whereas these values for CBDP primers were 15 to 26, 0.28 to 0.36, 3.82 to 6.94, and 4.74 to 7.96 with a mean of 19.87, 0.31, 5.35, and 6.24, respectively. Based on both marker systems, analysis of molecular variance (AMOVA) indicated that the portion of genetic diversity within species was more than among them. In both analyses, the highest values of the number of observed (Na) and effective alleles (Ne), Nei’s gene diversity (He), and Shannon’s information index (I) were estimated for Ae. cylindrica species. Conclusion The results of cluster analysis and population structure showed that SCoT and CBDP markers grouped all samples based on their genomic constitutions. In conclusion, the used markers are very effective techniques for the evaluation of the genetic diversity in wild relatives of wheat.

scholarly journals Cross Species/Genera Transferability of SSR Markers, Genetic Diversity and Population Structure Analysis in Gladiolus (Gladiolus × grandiflorus L.) Genotypes

2021 ◽  
Author(s):  
Varun Hiremath ◽  
Kanwar Pal Singh ◽  
Neelu Jain ◽  
Kishan Swaroop ◽  
Pradeep Kumar Jain ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Ssr Markers ◽  
Structure Analysis ◽  
Genetic Relationships ◽  
Crop Improvement ◽  
Test Analysis ◽  
Average Value ◽  
Population Structure Analysis ◽  
Genetic Diversity And Structure

Abstract Genetic diversity and structure analysis using molecular markers is necessary for efficient utilization and sustainable management of gladiolus germplasm. Genetic analysis of gladiolus germplasm using SSR markers is largely missing due to scarce genomic information. In the present investigation, we report 66.66% cross transferability of Gladiolus palustris SSRs whereas 48% of Iris EST-SSRs were cross transferable across the gladiolus genotypes used in the study. A total of 17 highly polymorphic SSRs revealed a total 58 polymorphic loci ranging from two to six in each locus with an average of 3.41 alleles per marker. PIC values ranged from 0.11 to 0.71 with an average value of 0.48. Four SSRs were selectively neutral based on Ewens-Watterson test. Analysis of genetic structure of 84 gladiolus genotypes divided whole germplasm into two subpopulations. 35 genotypes were assigned to subpopulation 1 whereas 37 to subpopulation 2 and rest of the genotypes recorded as admixture. Analysis of molecular variance indicated maximum variance (53.59%) among individuals within subpopulations whereas 36.55% of variation observed among individuals within total population. Least variation (9.86%) was noticed between two subpopulations. Moderate (FST = 0.10) genetic differentiation of two subpopulations was observed. Grouping pattern of population structure was consistent with UPGMA dendrogram based on simple matching dissimilarity coefficient (ranged from 01.6 to 0.89) and PCoA. Genetic relationships assessed among the genotypes of respective clusters assist the breeders in selecting desirable parents for crossing. SSR markers from present study can be utilized for cultivar identification, conservation and sustainable utilization of gladiolus genotypes for crop improvement.

scholarly journals Population structure and genetic diversity analysis in Sali (Oryza sativa) rice germplasm of Assam using microsatellite markers

2021 ◽  
Vol 58 (2) ◽  
pp. 279-286
Author(s):  
Sandhani Saikia ◽  
Pratap Jyoti Handique ◽  
Mahendra K Modi
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Genetic Improvement ◽  
Crop Improvement ◽  
Mean Value ◽  
Diversity Analysis ◽  
Rice Cultivars ◽  
Improvement Program ◽  
Information Index ◽  
Improvement Programs

Genetic diversity is the source of novel allelic combinations that can be efficiently utilized in any crop improvement program. To facilitate future crop improvement programs in rice, a study was designed to identify the underlying genetic variations in the Sali rice germplasms of Assam using SSR markers. The 129 SSR markers that were used in the study amplified a total of 765 fragments with an average of 5.93 alleles per locus. The Shannon's Information Index was found to be in the range from 0.533 to 1.786. The Polymorphism Information Content (PIC) fell into the range from 0.304 to 0.691 with a mean value of 0.55. The overall FST value was found to be 0.519 that indicated the presence of genetic differentiation amongst the genotypes used in the study. The Sali population was divided into two clusters. The information obtained from the present study will facilitate the genetic improvement of Sali rice cultivars.

Genetic diversity of under-utilized indigenous finger millet genotypes from Koraput, India for crop improvement

2020 ◽  
Author(s):  
Debabrata Panda ◽  
N. Hema Sailaja ◽  
Prafulla K. Behera ◽  
Kartik Lenka ◽  
Shyam S. Sharma ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Finger Millet ◽  
Crop Improvement

scholarly journals Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) accessions using single nucleotide polymorphism markers

2019 ◽  
Vol 17 (5) ◽  
pp. 412-420
Author(s):  
G. Afolayan ◽  
S. P. Deshpande ◽  
S. E. Aladele ◽  
A. O. Kolawole ◽  
I. Angarawai ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Sorghum Bicolor ◽  
Agronomic Traits ◽  
Crop Improvement ◽  
Single Nucleotide ◽  
Breeding Programs ◽  
Diversity Assessment ◽  
Crop Research ◽  
International Crop Research Institute ◽  
Private Alleles

AbstractSorghum (Sorghum bicolor (L.) Moench) is an important resource to the national economy and it is essential to assess the genetic diversity in existing sorghum germplasm for better conservation, utilization and crop improvement. The aim of this study was to evaluate the level of genetic diversity within and among sorghum germplasms collected from diverse institutes in Nigeria and Mali using Single Nucleotide Polymorphic markers. Genetic diversity among the germplasm was low with an average polymorphism information content value of 0.24. Analysis of Molecular Variation revealed 6% variation among germplasm and 94% within germplasms. Dendrogram revealed three groups of clustering which indicate variations within the germplasms. Private alleles identified in the sorghum accessions from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria and International Crop Research Institute for the Semi-Arid Tropics, Kano, Nigeria shows their prospect for sorghum improvement and discovery of new agronomic traits. The presence of private alleles and genetic variation within the germplasms indicates that the accessions are valuable resources for future breeding programs.

Defining and identifying crop landraces

2005 ◽  
Vol 3 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Tania Carolina Camacho Villa ◽  
Nigel Maxted ◽  
Maria Scholten ◽  
Brian Ford-Lloyd
Keyword(s):  
Genetic Diversity ◽  
Crop Improvement ◽  
Farming Systems ◽  
Traditional Farming ◽  
Crop Species ◽  
High Genetic Diversity ◽  
Working Definition ◽  
Landrace Diversity ◽  
Cultivated Plant ◽  
Historical Origin

Awareness of the need for biodiversity conservation is now universally accepted, but most often recent conservation activities have focused on wild species. Crop species and the diversity between and within them has significant socioeconomic as well as heritage value. The bulk of genetic diversity in domesticated species is located in traditional varieties maintained by traditional farming systems. These traditional varieties, commonly referred to as landraces, are severely threatened by genetic extinction primarily due to their replacement by modern genetically uniform varieties. The conservation of landrace diversity has been hindered in part by the lack of an accepted definition to define the entity universally recognized as landraces. Without a definition it would be impossible to prepare an inventory and without an inventory changes in landrace constituency could not be recognized over time. Therefore, based on a literature review, workshop discussion and interviews with key informants, common characteristics of landraces were identified, such as: historical origin, high genetic diversity, local genetic adaptation, recognizable identity, lack of formal genetic improvement, and whether associated with traditional farming systems. However, although these characteristics are commonly present they are not always all present for any individual landrace; several crop-specific exceptions were noted relating to crop propagation method (sexual or asexual), breeding system (self-fertilized or cross-fertilized species), length of formal crop improvement, seed management (selection or random propagation) and use. This paper discusses the characteristics that generally constitute a landrace, reviews the exceptions to these characteristics and provides a working definition of a landrace. The working definition proposed is as follows: ‘a landrace is a dynamic population(s) of a cultivated plant that has historical origin, distinct identity and lacks formal crop improvement, as well as often being genetically diverse, locally adapted and associated with traditional farming systems’.

scholarly journals Genetic diversity of released Malaysian rice varieties based on single nucleotide polymorphism markers

2020 ◽  
Vol 56 (No. 2) ◽  
pp. 62-70 ◽  
Author(s):  
Shahril Ab Razak ◽  
Nor Helwa Ezzah Nor Azman ◽  
Rahiniza Kamaruzaman ◽  
Shamsul Amri Saidon ◽  
Muhammad Fairuz Mohd Yusof ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Single Nucleotide Polymorphism ◽  
Crop Improvement ◽  
Snp Markers ◽  
Group Method ◽  
Chromosome 11 ◽  
Nucleotide Polymorphism ◽  
Rice Varieties ◽  
Single Nucleotide ◽  
K Value

Understanding genetic diversity is a main key for crop improvement and genetic resource management. In this study, we aim to evaluate the genetic diversity of the released Malaysian rice varieties using single nucleotide polymorphism (SNP) markers. A total of 46 released Malaysian rice varieties were genotyped using 1536 SNP markers to evaluate their diversity. Out of 1536 SNPs, only 932 SNPs (60.7%) represented high quality alleles, whereas the remainder either failed to amplify or had low call rates across the samples. Analysis of the 932 SNPs revealed that a total of 16 SNPs were monomorphic. The analysis of the SNPs per chromosome revealed that the average of the polymorphic information content (PIC) value ranged from 0.173 for chromosome 12 to 0.259 for chromosome 11, with an average of 0.213 per locus. The genetic analysis of the 46 released Malaysian rice varieties using an unweighted pair group method with arithmetic mean (UPGMA) dendrogram revealed the presence of two major groups. The analysis was supported by the findings from the STRUCTURE analysis which indicated the ∆K value to be at the highest peak at K = 2, followed by K = 4. The pairwise genetic distance of the shared alleles showed that the value ranged from 0.000 (MR159–MR167) to 0.723 (MRIA–Setanjung), which suggested that MR159 and MR167 were identical, and that the highest dissimilarity was detected between MRIA 1 and Setanjung. The results of the study will be very useful for the variety identification, the proper management and conservation of the genetic resources, and the exploitation and utilisation in future breeding programmes.

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