Effect of Hybrid Breeding on Genetic Diversity in Maize

2015 ◽  
pp. 119-126 ◽  
Author(s):  
J.S.C. Smith ◽  
D.N. Duvick ◽  
O.S. Smith ◽  
A. Grunst ◽  
S.J. Wall
Keyword(s):  
Genetic Diversity ◽  
Hybrid Breeding

scholarly journals Applications of molecular markers in Genetic Diversity Studies of maize

2020 ◽  
Vol 37 (1) ◽  
pp. 101-108
Author(s):  
Degife Asefa Zebire
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Inbred Lines ◽  
Hybrid Breeding ◽  
Diversity Analysis ◽  
Crop Species ◽  
Heterotic Groups ◽  
Genetic Diversity Analysis ◽  
Diversity Studies ◽  
Genetic Diversity Study

Molecular markers are efficient for exploiting variations in genotypes as they are not influenced by environmental factors and also speed up breeding programs. They are used to detect large numbers of distinct divergence between genotypes at the DNA level. Genetic diversity study helps to estimate the relationship between inbred lines to make the best hybrid combinations. Lines which are clustered in different heterotic groups are considered as the best hybrid combinations to carry out further breeding activities. Molecular markers are used to meet a number of objectives, including genetic diversity analysis and prediction of hybrid performances in divergent crop species. Agro-morphological and molecular markers have been utilized to study genetic diversity so far. In maize, the uses of molecular markers are important for the evaluation of genetic diversity of inbred lines and in clustering them into heterotic groups. These markers determine genetic similarity of the lines and are used to assess the genetic diversity of maize. Molecular markers have proven valuable for genetic diversity analysis of many crop species and genetically diverse lines are important to improve hybrid breeding. Keyword: Molecular marker; Genetic diversity; Genetic variation, Diversity Array technology; cluster analysis

scholarly journals Genetic diversity among tropical maize inbred lines as revealed by SSR markers

2020 ◽  
pp. 2010-2019
Author(s):  
Maizura Abu Sin ◽  
Ghizan Saleh ◽  
Nur Ashikin Psyquay Abdullah ◽  
Pedram Kashiani
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Similarity Index ◽  
Inbred Lines ◽  
Hybrid Breeding ◽  
Heterotic Groups ◽  
Breeding Programs ◽  
Maize Inbred Lines

Genetic diversity and phenotypic superiority are important attributes of parental inbred lines for use in hybrid breeding programs. In this study, genetic diversity among 30 maize (Zea mays L.) inbred lines comprising of 28 introductions from the International Maize and Wheat Improvement Center (CIMMYT), one from Indonesia and a locally developed, were evaluated using 100 simple sequence repeat (SSR) markers, as early screening for potential parents of hybrid varieties. All markers were polymorphic, with a total of 550 unique alleles detected on the 100 loci from the 30 inbred lines. Allelic richness ranged from 2 to 13 per locus, with an average of 5.50 alleles (na). Number of effective alleles (ne) was 3.75 per locus, indicating their high effectiveness in revealing diversity among inbred lines. Average polymorphic information content (PIC) was 0.624, with values ranging from 0.178 to 0.874, indicating high informativeness of the markers. High gene diversity was observed on Chromosomes 8 and 4, with high number of effective alleles, indicating their potential usefulness for QTL analysis. The UPGMA dendrogram constructed identified four heterotic groups within a similarity index of 0.350, indicating that these markers were able to group the inbred lines. The three-dimensional PCoA plot also supports the dendrogram grouping, indicating that these two methods complement each other. Inbred lines in different heterotic groups have originated from different backgrounds and population sources. Information on genetic diversity among the maize inbred lines are useful in developing strategies exploiting heterosis in breeding programs

Assessment of genetic diversity in advanced breeding lines derived from intraspecific crosses of garden pea (Pisum sativum L.)

2018 ◽  
Author(s):  
Bhallan Singh Sekhon ◽  
Akhilesh Sharma ◽  
Viveka Katoch . ◽  
Rakesh K. Kapila ◽  
V. K. Sood
Keyword(s):  
Genetic Diversity ◽  
Hybrid Breeding ◽  
Internodal Length ◽  
Garden Pea ◽  
Breeding Lines ◽  
Pisum Sativum L ◽  
Breeding Programmes ◽  
Pedigree Selection ◽  
Direct Use ◽  
Intraspecific Hybrid

An intraspecific hybrid breeding program involving six crosses, Palam Sumool (PS) × Palam Priya, PS × Pb-89, PS × Azad P-1, PS × Palam Triloki and VRPMR10 × Sugar Giant, Green Pearl × DPP-9411 was initiated in 2006 onwards followed by pedigree selection, resulted in isolation of 45 genotypes with desirable attributes. These progenies along with five recommended varieties were evaluated during 2014-15 to assess degree of divergence. A considerable genetic diversity was observed among genotypes, dispersed in 18 diverse clusters. Of these, 17 were monogenotypic while cluster I had maximum genotypes. Internodal length contributed maximum towards total genetic divergence followed by nodes per plant, protein content and average pod weight. Superior performing genotypes viz., ‘DPP-2011-SP-7’, ‘DPP-2011-SP-17’, and ‘DPP-2011-SP-24’ from cluster I and ‘DPP-2011-SP-6’, ‘DPP-2011-SP-22’ ‘DPPMR-09-1’, ‘DPPMR-09-2’, ‘DPP-2011-SN-5’ and ‘Palam Triloki’ from monogenotypic clusters offer promise for their direct use as varieties and as potential parents in future breeding programmes.

scholarly journals Genomic diversity in pearl millet inbred lines derived from landraces and improved varieties

2020 ◽  
Author(s):  
Desalegn D. Serba ◽  
Ghislain Kanfany ◽  
Davina Rhodes ◽  
Paul St. Amand ◽  
Amy Bernardo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Pearl Millet ◽  
Nutritional Quality ◽  
Inbred Lines ◽  
Genomic Diversity ◽  
Hybrid Breeding ◽  
Heterotic Groups ◽  
Improved Varieties ◽  
Different Levels

Abstract Background: Genetic improvement of pearl millet is lagging behind most of the major crops. Development of genomic resources is expected to expedite breeding for improved agronomic traits, stress tolerance, yield, and nutritional quality. Genotyping a breeding population with high throughput markers enables exploration of genetic diversity, population structure, and linkage disequilibrium (LD) which are important preludes for marker-trait association studies and application of genomic-assisted breeding. Results: Genotyping-by-sequencing (GBS) libraries of 309 inbred lines derived from landraces and improved varieties from Africa and India generated 54,770 high quality single nucleotide polymorphism (SNP) markers. On average one SNP per 29 Kb was mapped in the reference genome, with the telomeric regions more densely mapped than the pericentromeric regions of the chromosomes. Population structure analysis using 30,208 SNPs evenly distributed in the genome divided 309 accessions into five subpopulations with different levels of admixture. Pairwise genetic distance (GD) between accessions varied from 0.09 to 0.33 with the average distance of 0.28. Rapid LD decay implied low tendency of markers inherited together. Genetic differentiation estimates were the highest between subgroups 4 and 5, and the lowest between subgroups 1 and 2. Conclusions: Population genomic analysis of pearl millet inbred lines derived from diverse geographic and agroecological features identified five subgroups mostly following pedigree differences with different levels of admixture. It also revealed the prevalence of high genetic diversity in pearl millet, which is very useful in defining heterotic groups for hybrid breeding, trait mapping, and holds promise for improving pearl millet for yield and nutritional quality. The short LD decay observed suggests an absence of persistent haplotype blocks in pearl millet. The diverse genetic background of these lines and their low LD make this set of germplasm useful for traits mapping.

scholarly journals Genomic diversity in pearl millet inbred lines derived from landraces and improved varieties

2020 ◽  
Author(s):  
Desalegn D. Serba ◽  
Ghislain Kanfany ◽  
Davina Rhodes ◽  
Paul St. Amand ◽  
Amy Bernardo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Pearl Millet ◽  
Nutritional Quality ◽  
Inbred Lines ◽  
Genomic Diversity ◽  
Hybrid Breeding ◽  
Heterotic Groups ◽  
Improved Varieties ◽  
Different Levels

Abstract Background: Genetic improvement of pearl millet is lagging behind most of the major crops. Development of genomic resources is expected to expedite breeding for improved agronomic traits, stress tolerance, yield, and nutritional quality. Genotyping a breeding population with high throughput markers enables exploration of genetic diversity, population structure, and linkage disequilibrium (LD) which are important preludes for marker-trait association studies and application of genomic-assisted breeding. Results: Sequencing the genotyping-by-sequencing (GBS) libraries of 309 inbred lines derived from landraces and improved varieties from Africa and India generated 54,770 high quality single nucleotide polymorphism (SNP) markers. On average one SNP per 29 Kb was mapped in the reference genome, with the telomeric regions more densely mapped than the pericentromeric regions of the chromosomes. Population structure analysis using 30,208 SNPs evenly distributed in the genome divided 309 accessions into five subpopulations with different levels of admixture. Pairwise genetic distance (GD) between accessions varied from 0.09 to 0.33 with the average distance of 0.28. Rapid LD decay implied low tendency of markers inherited together. Genetic differentiation estimates were the highest between subgroups 4 and 5, and the lowest between subgroups 1 and 2. Conclusions: Population genomic analysis of pearl millet inbred lines derived from diverse geographic and agroecological features identified five subgroups mostly following pedigree differences with different levels of admixture. It also revealed the prevalence of high genetic diversity in pearl millet, which is very useful in defining heterotic groups for hybrid breeding, trait mapping, and holds promise for improving pearl millet for yield and nutritional quality. The short LD decay observed suggests an absence of persistent haplotype blocks in pearl millet. The diverse genetic background of these lines and their low LD make this set of germplasm useful for traits mapping.

Genetic diversity and structure of improved indica rice germplasm

2014 ◽  
Vol 12 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Kai Wang ◽  
Fulin Qiu ◽  
Madonna Angelita Dela Paz ◽  
Jieyun Zhuang ◽  
Fangming Xie
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Latin American ◽  
Hybrid Rice ◽  
Hybrid Breeding ◽  
Model Based ◽  
Population Structure Analysis ◽  
Wide Range ◽  
Genetic Diversity And Structure ◽  
Breeding Programmes

The characterization of genetic diversity and structure for improved cultivated varieties/elite lines is tremendously important to assist breeders in parental selection for inbred and hybrid breeding and heterotic group construction. In this study, a total of 737 improved indica varieties/lines developed recently and/or widely used by present indica breeding programmes worldwide were genotyped with a 384-single-nucleotide polymorphism assay. Model-based population structure analysis revealed the presence of two major groups with six subgroups (SGs), wherein no clear correlation was found between the groups/SGs and breeding programmes or geographical origin of the accessions. Over half of the accessions (51.8%) appeared to have less than 0.6 memberships assigned to any one of the six model-based groups, highlighting the wide range of gene flow within improved indica varieties/lines and the genetic integration of valuable alleles shared by ancestries among improved high-yielding varieties/lines through germplasm exchanges. Distance-based clustering revealed that Latin-American cultivated indica lines have tended to form their own ecological cline, which could serve as a potential heterotic ecotype for hybrid rice breeding, although they are still closely related to Asian indica lines. African cultivated indica lines, on the other hand, have not yet formed their own ecological cline. It was also observed that the most well-known hybrid rice parents, Zhenshan97B and Minghui63, were unexpectedly clustered in the same SG with a relatively narrow genetic distance, which suggests that a significant genetic distance between parents is not a prerequisite for all elite hybrid rice lines with high heterosis.

scholarly journals Changes of genetic diversity of maize inbred lines over four decades of hybrid breeding in the Bc institute revealed by SSR markers

Genetika ◽  
2015 ◽  
Vol 47 (1) ◽  
pp. 233-243
Author(s):  
Ivica Buhinicek ◽  
Mirko Jukic ◽  
Hrvoje Sarcevic ◽  
Jerko Gunjaca ◽  
Zdravko Kozic ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Inbred Lines ◽  
Hybrid Breeding ◽  
Maize Breeding ◽  
Hybrid Production ◽  
The Past ◽  
Maize Inbred Lines ◽  
Heterotic Pattern ◽  
Private Alleles

In this paper, changes of genetic diversity of the most important maize inbred lines used for hybrid production within the Bc Institute in the 1970s, 1980s, 1990s and 2000s were examined using the SSR markers. The average number of alleles per SSR locus was 3.14, 3.43, 3.07 and 3.25 for lines from 1970s, 1980s, 1990s and 2000s, whereas the number of private alleles for the same four decades was 8, 4, 0 and 6, respectively. Mean genetic distance among inbreds within decades steadily decreased over time from 0.64 in 1970s to 0.57 in 2000s, but the observed differences were not statistically significant. The clustering of the studied inbred lines indicates the exploitation of a known BSSS x LSC heterotic pattern within the Bc Institute maize breeding program. The overall results show that recycled inbred lines within these pools do not decline in genetic variation over the past 40 years.

scholarly journals Combining ability and heterosis in plant improvement

2021 ◽  
pp. 108-117
Author(s):  
Begna Temesgen
Keyword(s):  
Genetic Diversity ◽  
Combining Ability ◽  
Crop Improvement ◽  
Critical Factor ◽  
Hybrid Vigor ◽  
Hybrid Breeding ◽  
F1 Hybrids ◽  
Gene Pools ◽  
Crop Species ◽  
Heterotic Groups

Information on combining ability and heterosis of parents and crossings is crucial in breeding efforts. Genetic variety is crucial to the effectiveness of yield improvement efforts because it helps to broaden gene pools in any given crop population. The genotype's ability to pass the intended character to the offspring is referred to as combining ability. As a result, information on combining ability is required to determine the crossing pairs in the production of hybrid varieties. Heterosis is the expression of an F1 hybrid's dominance over its parents in a given feature, as measured not by the trait's absolute value, but by its practical use. To put it another way, heterosis is defined as an increase in the character value of F1 hybrids when compared to the average value of both parents. A plant breeder's ultimate goal is to achieve desirable heterosis (hybrid vigor). In a variety of crop species, heterosis has been widely employed to boost output and extend the adaptability of hybrid types. A crucial requirement for discovering crosses with significant levels of exploitable heterosis is knowledge of the quantity of heterosis in different cross combinations. Any crop improvement program's success is contingent on the presence of a significant level of genetic diversity and heritability. The lack of a broad genetic foundation is the most significant constraint to crop improvement and a major bottleneck in breeding operations. Heterosis is a critical factor in hybrid generation, particularly for traits driven by non-additive gene activity. To get the most out of heterosis for hybrid cultivar production, germplasm must be divided into distinct heterotic groups. Similarly, knowledge on genetic diversity is critical for hybrid breeding and population improvement initiatives because it allows them to analyze genetic diversity, characterize germplasm, and categorize it into different heterotic groupings. In general, general combining ability is used to detect a line's average performance in a hybrid combination, whereas specific combining ability is used to find circumstances where definite combinations perform better or worse than expected based on the mean performance of the lines involved.

scholarly journals Assessment of genetic diversity of yellow-seeded rapeseed (Brassica napus L.) accessions by AFLP markers

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 105-112 ◽  
Author(s):  
Ch. Yu ◽  
L. Leišová ◽  
V. Kučera ◽  
M. Vyvadilová ◽  
J. Ovesná ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Brassica Napus ◽  
Geographic Origin ◽  
Aflp Markers ◽  
Hybrid Breeding ◽  
Pedigree Information ◽  
Aflp Analysis ◽  
Polymorphic Markers ◽  
Principal Coordinates Analysis ◽  
Principal Coordinates

The genetic diversity of 35 yellow-seeded <i>Brassica napus</i> L. accessions originating from China, Czech Republic and Poland was assessed by means of Amplified Fragment Length Polymorphism (AFLP) markers based on multiplex PCR using multi-colour fluorescent-labelled primers. Five brown-seeded accessions originating from China and France were selected as outliers. In total, 632 peaks were generated by AFLP reaction using 18 primer combinations. Only distinctly polymorphic markers among them were scored. In total, 242 polymorphic markers were detected with an average of 13.4 markers per primer combination. The AFLP analysis separated forty studied accessions into Chinese and European groups by UPGMA clustering and Principal Coordinates Analysis (PCA). The grouping of accessions based on the cluster analysis and PCA was generally consistent with known pedigree information and geographic origin. Notable geographical divergence was found between Chinese and European yellow-seeded accessions. This information is useful for yellow-seeded hybrid breeding and encouraging breeders to exchange their germplasm as to enlarge the genetic diversity of breeding accessions.

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