Isoenzymatic variation in the germplasm of Brazilian races of maize (Zea mays L.)

There are more than 200 races of maize (Zea mays L.) divided into three groups (ancient commercial races, the recent commercial races, and indigenous races). Although the indigenous races have no commercial value, they have many important characteristics which can be incorporated into maize breeding programs. Most Brazilian indigenous germplasm race stocks were collected at least 40 years ago, and nothing is known of the genetic variability present in this germplasm. The genetic variability was assayed in 15 populations from four indigenous races of maize (Caingang, Entrelaçado, Lenha and Moroti) and five indigenous cultivars, using five isoenzymatic systems encoded by 14 loci. The analysis revealed a low level of variability among the samples studied. Overall, the mean number of alleles/polymorphic locus was three, 64.3% of the loci analyzed being polymorphic and the estimated heterozygosity was 0.352. The mean number of alleles/polymorphic locus per population was 1.6. A mean of 47.5% of the loci were polymorphic. The mean expected heterozygosity was 0.195, the mean genetic identity was 0.821 and the proportion of total genetic diversity partitioned among populations (Gst) was 0.156. A founder effect could explain the low variability detected.

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Is it possible to obtain zero estimates of genetic diversity? A case study of the Nigerian indigeneous goat breeds at the β-lactoglobulin gene locus

Biotechnology in Animal Husbandry ◽

10.2298/bah1704375e ◽

2017 ◽

Vol 33 (4) ◽

pp. 375-388

Author(s):

Emeka Ezewudo ◽

Geka Abubakar ◽

Sunday Egena ◽

Olushola Alabi

Keyword(s):

Genetic Diversity ◽

Genetic Distance ◽

Gene Locus ◽

Polymorphic Locus ◽

Information Index ◽

Expected Heterozygosity ◽

Goat Population ◽

The Mean ◽

Β Lactoglobulin

The current investigation was conducted to appraise the genetic diversity and genetic distance of three goat populations namely; Red Sokoto, Sahel and West African Dwarf (WAD), in Nigeria, making use of blood samples collected from 20, 20 and 20 individual from which blood DNAs were extraction, respectively. The DNAs extracted were used to study polymorphism at the ?-lactoglobulin gene locus using RLFP-PCR process. Results revealed that the mean total number of alleles was 1 while the effective number of alleles was also 1. The percentage of polymorphic locus was 0% while Shannon?s information index, observed homozygousity, expected heterozygosity, unbiased expected heterozygosity and inbreeding coefficient (F) were all observed to be 0.000. The pairwise Fst was 0.000 between all the breeds of goats. Variation within and between the populations of goats was 0% at p>0.05. The genetic distance between the goat breeds was 0.000. The present study revealed that RLFP-PCR may not be a powerful tool for the study of the ?-lactoglobulin gene locus and hence other methodologies should be employed for a broader judgment on the genetic status of the goat population at the locus.

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Isozyme analysis of genetic variability and population structure of Lathyrus sativus L. germplasm

Legume Research - An International Journal ◽

10.18805/lr-441 ◽

2019 ◽

Author(s):

R. H. Sammour ◽

A-E. Mustafa ◽

M.- El-Sheikh ◽

A. A. Alatar ◽

W. Taher

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Genetic Variability ◽

Random Mating ◽

Lathyrus Sativus ◽

Isozyme Analysis ◽

Expected Heterozygosity ◽

The Mean ◽

Low Levels ◽

Lathyrus Sativus L

This work aimed at exploring the genetic variability, population structure and relationships of Lathyrus sativus L. germplasm using isozyme analysis. The data of isozyme analysis revealed 12 putative polymorphic loci of a total 33 alleles, indicating that studied accessions express good allelic richness and had an apparent rate of allogamy. The mean average of the expected heterozygosity (0.483) was more than the mean average of the observed heterozygosity (0.449) suggesting an apparent rate of allogamy taking place in Lathyrus sativus L. The average of total heterozygosity (HT) and intra-accessional genetic diversity (HS) were 0.559 and 0.428 respectively indicating that majority of genetic diversity was intra-accessional. The low levels and non-significant of genetic diversity among accessions (DST = 0.190, X2 = 62.59, p = 0.029) were probably indicative of occurrence of several gene flows. The coefficient of gene differentiation (GST) showed significant variation, suggesting the heterogonous distribution of L. sativus accessions among different geographic regions. The mean average of FST was 0.327, suggesting the occurrence of random mating system for the studied accessions and reflecting adaptation to strong environmental dissimilarities. Cluster analysis based on isozyme data suggested that the environment had no influence on the genetic diversity and confirmed that Lathyrus sativus L. had a polyphyletic origin.

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Genetic variability in Tambaqui generations of the breeding program in the Central-West Region of Brazil

Semina Ciências Agrárias ◽

10.5433/1679-0359.2021v42n3supl1p1785 ◽

2021 ◽

Vol 42 (3Supl1) ◽

pp. 1785-1796

Author(s):

Angela Maria Urrea-Rojas ◽

◽

Annaiza Braga Bignardi ◽

Felipe Pinheiro de Souza ◽

Ed Christian Suzuki de Lima ◽

...

Keyword(s):

Genetic Diversity ◽

Genetic Variability ◽

Native Species ◽

Genetic Improvement ◽

Improvement Program ◽

Breeding Programs ◽

Mato Grosso ◽

West Region ◽

Fish Breeding ◽

The Mean

The implementation of fish breeding programs in Brazil has brought significant results in the productivity of tilapia. However, the insertion of native species with great potential (such as Tambaqui Colossoma macropomum) in these programs is still recent, and thus requires genetic information for monitoring and enabling their consolidation into the programs. The objective of the present study was to evaluate the genetic diversity of the parental generation (G0) and two consecutive generations (G1 and G2) in the C. macropomum genetic improvement program, located in the municipality of Sorriso, Mato Grosso, Brazil. Ninety caudal fin samples were collected (30 samples per generation) for DNA extraction. The genetic study implemented seven microsatellite markers (Cm1A8, Cm1A11, Cm1D1, Cm1E3, Cm1F4, Cm1F5, and Cm1H8). A total of 17 alleles were amplified, with variations in the mean number between four to two alleles per locus. The size per locus ranged from 170 to 360 bp. The average inbreeding coefficient was 0.126 (G0), -0.040 (G1), and 0.131 (G2). No null or exclusive alleles were found. The observed heterozygosity values for G1 and G2 demonstrated the preservation of genetic variability (0.453 and 0.409, respectively). In conclusion, the genetic diversity of the parental generation (G0) and the two progenies generations (G1 and G2) were adequate, which demonstrates that the genetic improvement program was conducted correctly; however, it is important to continue to evaluations the genetic diversity of the future progeny.

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Variability and traits association in maize (Zea mays L.) for yield and yield associated characters

Journal of the Bangladesh Agricultural University ◽

10.3329/jbau.v15i2.35062 ◽

2017 ◽

Vol 15 (2) ◽

pp. 193-198

Author(s):

A Ferdoush ◽

MA Haque ◽

MM Rashid ◽

MAA Bari

Keyword(s):

Zea Mays ◽

Genetic Variability ◽

Grain Yield ◽

Zea Mays L ◽

Dry Weight ◽

Kernel Weight ◽

High Yield ◽

Phenotypic Traits ◽

Cereal Crop ◽

Breeding Programs

Maize (Zea mays L.) is world’s third most important cereal crop that has a remarkable productive potential in Bangladesh. In Bangladesh, maize is the second most important cereal crop in terms of production. The selection for high yield with desirable traits depends on the genetic variability in the existing germplasm. Successful breeding programs need adequate genetic variation for selection and improvement based on necessity. The research was conducted in the experimental farm of the Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh during November 2015 to April 2016. The aim of this study was to evaluate the performance of 20 maize genotypes based on their yield and yield contributing characters to determine existing genetic variability. The extrapolated ANOVA for different yield contributing parameters showed a high degree of variation among the genotypes used. Correlation co-efficient analysis revealed that yield plant−1 (g) had positive and significant association with ear girth (cm), 1000-kernel weight (g), yield plot−1 (g), grain yield (tha−1) with dry weight. The genotypes differed significantly for most of the phenotypic traits. The phenotypic co-efficient of variation (PCV) was higher than genotypic co-efficient of variation (GCV) in all traits studied indicating that those traits were interacted with the environment. The traits under study expressed wide heritability estimates (26.81% to 99.95%). Among the characters, highest heritability was recorded for 1000-kernel weight (g). High heritability along with high genetic advance was noticed for 1000-kernel weight (g), yield plot−1 (g)and grain yield (tha−1). Considering different desirable traits P-12, Popcorn, V90-1, 988 were observed as superior genotypes. The data would be useful for proper identification and selection of appropriate parents in breeding programs to develop new maize varieties.J. Bangladesh Agril. Univ. 15(2): 193-198, December 2017

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Heterosis, habilidad combinatoria y diversidad genética en híbridos comerciales de maíz (Zea mays L).

Agronomía Mesoamericana ◽

10.15517/am.v11i1.17360 ◽

2006 ◽

Vol 11 (1) ◽

pp. 113

Author(s):

Alfredo De la Rosa ◽

Humberto De León ◽

Gaspar Martínez ◽

Froylan Rincón

Keyword(s):

Genetic Diversity ◽

Zea Mays ◽

Genetic Distance ◽

Combining Ability ◽

Zea Mays L ◽

Genetic Distances ◽

Breeding Program ◽

Specific Combining Ability ◽

Maize Breeding ◽

Genetic Value

Knowledge about the combining ability, genetic diversity and heterosis of germoplasm from a maize breeding program is essential for hybrids and varieties development. The objetives of this study were (1) To identify commercial hybrids with high genetic value (GCA and heterosis) useful for initiating a maize breeding program to produce and improved hybrids, varieties and synthetics; (2) To demonstrate that is feasible to create a maize breeding program from commercial hybrids. Estimates of general (GCA) and specific combining ability (SCA) were obtained using the method IV of Griffing (1956) and the genetic distances were estimated according to the method suggested by Troyer (1988). The best crosses were AS910 X AS4450 and PP9538 X AS948 having a yield of 17.538 and 17.463 t/ha respectively; the same crosses had the highest values of SCA. The crosses with the highest values of heterosis over the midparent were PP9539 X AN453 and PP9603 X PP9539 with 11,35 and 11,13 percent respectively. The highest positive values of GCA effects were obtained from hybrids PP9539 and AN447 with 1.168 and 0.684 t/ha respectively;. and the hybrids with the best heterosis were PP9539 ( 2.269 ) and A7500 ( 1.170 ). The most related hybrids were AS910 and AN450 with a genetic distance of 0,033 and heterosis of -47,68 percent whereas the most diverse were AN454 and A7500 with a genetic distance of 1.418 and heterosis of 12,26 %.

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Genetic Variability and Genotypic, Phenotypic Correlation Studies for Yield and Related Traits In Single Cross Hybrids of Maize (Zea Mays L.)

Science Journal of University of Zakho ◽

10.25271/2014.2.1.143 ◽

2014 ◽

Vol 2 (1) ◽

pp. 138-145

Author(s):

Mohammed Mohammed

Keyword(s):

Zea Mays ◽

Genetic Variability ◽

Zea Mays L ◽

Phenotypic Correlation ◽

Correlation Studies ◽

Single Cross ◽

Single Cross Hybrids

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Genetic variability and traits association in maize (Zea mays L.) varieties for growth and yield traits

Heliyon ◽

10.1016/j.heliyon.2021.e07939 ◽

2021 ◽

pp. e07939

Author(s):

Bigul Thapa Magar ◽

Subash Acharya ◽

Bibek Gyawali ◽

Kiran Timilsena ◽

Jharana Upadhayaya ◽

...

Keyword(s):

Zea Mays ◽

Genetic Variability ◽

Zea Mays L ◽

Growth And Yield ◽

Yield Traits

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Genetic diversity of Avena strigosa Schreb. ecotypes on the basis of isoenzyme markers

Biodiversity Research and Conservation ◽

10.2478/v10119-009-0013-3 ◽

2009 ◽

Vol 15 (1) ◽

pp. 23-28 ◽

Cited By ~ 4

Author(s):

Katarzyna Kubiak

Keyword(s):

Genetic Diversity ◽

Genetic Similarity ◽

Avena Strigosa ◽

Total Genetic Diversity ◽

Geographical Regions ◽

The World ◽

Total Variability ◽

The Mean ◽

Intrapopulation Diversity ◽

Very High

Genetic diversity ofAvena strigosaSchreb. ecotypes on the basis of isoenzyme markersGenetic diversity was analyzed in 19 ecotypes of the diploid oatA. strigosaoriginating from various geographical regions of the world. Six isoenzyme systems (AAT, ACP, EST, LAP, MDH, PX) were studied and 16 loci were identified. Only two loci (Est4andMdh2) were polymorphic. Ecotypes were characterized by the percentage of polymorphic loci (P=3.3%), the mean number of alleles per locus (A=1.04) and intrapopulation diversity (HS=0.013). Total genetic diversity (HT=0.07) and interpopulation diversity (DST=0.057) were examined as well. The value of the coefficient of gene differentiation (GST=0.821) indicated that diversity among populations was an important contributor to total variability. Genetic similarity betweenA. strigosapopulations was very high (IN=0.94). Cluster analysis did not demonstrate strongly differentiated groups among the ecotypes examined.

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