scholarly journals Genetic diversity and population structure of Heteropogon contortus L. germplasm collected from diverse agro-climatic regions in India and development of a core germplasm set

2021 ◽  
Vol 9 (3) ◽  
pp. 359-370
Author(s):  
Ajoy Kumar Roy ◽  
Devendra Ram Malaviya ◽  
Pankaj Kaushal ◽  
Sanat Kumar Mahanta ◽  
Rupali Tewari ◽  
...  

Heteropogon contortus, an important constituent of major grasslands of India, Australia and many countries in Africa, Asia and the Americas, is important for pasture and grassland productivity. Hence genetic improvement of the grass needs attention. A genetic variability study, including development of a core subset, was carried out by evaluating 235 accessions collected from different agro-ecological zones of India. The study, based on 16 metric and 14 non-metric traits along with 8 nutritional parameters, indicated that considerable genetic variability existed among the germplasm and selection could result in identification of suitable types for target environments. Clustering and subclustering was performed to select 35 accessions to form a core subset. The statistical analysis indicated that the core subset captured almost all the variability present in the entire germplasm. The study will help researchers to focus future studies on this core subset in developing genetic improvement programs.

Author(s):  
C. Montagnon ◽  
A. Mahyoub ◽  
W. Solano ◽  
F. Sheibani

AbstractWhilst it is established that almost all cultivated coffee (Coffea arabica L.) varieties originated in Yemen after some coffee seeds were introduced into Yemen from neighboring Ethiopia, the actual coffee genetic diversity in Yemen and its significance to the coffee world had never been explored. We observed five genetic clusters. The first cluster, which we named the Ethiopian-Only (EO) cluster, was made up exclusively of the Ethiopian accessions. This cluster was clearly separated from the Yemen and cultivated varieties clusters, hence confirming the genetic distance between wild Ethiopian accessions and coffee cultivated varieties around the world. The second cluster, which we named the SL-17 cluster, was a small cluster of cultivated worldwide varieties and included no Yemen samples. Two other clusters were made up of worldwide varieties and Yemen samples. We named these the Yemen Typica-Bourbon cluster and the Yemen SL-34 cluster. Finally, we observed one cluster that was unique to Yemen and was not related to any known cultivated varieties and not even to any known Ethiopian accession: we name this cluster the New-Yemen cluster. We discuss the consequences of these findings and their potential to pave the way for further comprehensive genetic improvement projects for the identification of major resilience/adaptation and cup quality genes that have been shaped through the domestication process of C. arabica.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 342
Author(s):  
Elena Corredoira ◽  
Rita L. Costa

The increasing degradation of forests, together with a higher demand for wood and fruit, has led to the need for more efficient trees adapted to the current climatic conditions and, thus, to the need for genetic improvement programs [...]


2014 ◽  
Vol 139 (5) ◽  
pp. 547-552 ◽  
Author(s):  
Karen R. Harris-Shultz ◽  
Susana Milla-Lewis ◽  
Aaron J. Patton ◽  
Kevin Kenworthy ◽  
Ambika Chandra ◽  
...  

Zoysiagrass (Zoysia sp.) is used as a warm-season turfgrass for lawns, parks, and golf courses in the warm, humid and transitional climatic regions of the United States. Zoysiagrass is an allotetraploid species (2n = 4x = 40) and some cultivars are known to easily self- and cross-pollinate. Previous studies showed that genetic variability in the clonal cultivars Emerald and Diamond was likely the result of contamination (seed production or mechanical transfer) or mislabeling. To determine the extent of genetic variability of vegetatively propagated zoysiagrass cultivars, samples were collected from six commercially available zoysiagrass cultivars (Diamond, Emerald, Empire, JaMur, Meyer, Zeon) from five states (Arkansas, Florida, Georgia, North Carolina, Texas). Two of the newest cultivar releases (Geo and Atlantic) were to serve as outgroups. Where available, one sample from university research plots and two samples from sod farms were collected for each cultivar per state. Forty zoysiagrass simple sequence repeat (SSR) markers and flow cytometry were used to compare genetic and ploidy variation of each collected sample to a reference sample. Seventy-five samples were genotyped and an unweighted pair group method with arithmetic mean clustering revealed four groups. Group I (Z. japonica) included samples of ‘Meyer’ and Empire11 (‘Empire’ sample at location #11), Group II (Z. japonica × Z. pacifica) included samples of ‘Emerald’ and ‘Geo’, Group III (Z. matrella) included samples of ‘Diamond’ and ‘Zeon’, and Group IV (Z. japonica) consisted of samples from ‘Empire’, ‘JaMur’, ‘Atlantic’, and Meyer3 (‘Meyer’ at sample location #3). Samples of ‘Empire’, ‘Atlantic’, and ‘JaMur’ were indistinguishable with the markers used. Four samples were found to have alleles different from the respective reference cultivar, including two samples of ‘Meyer’, one sample of ‘Empire’, and one sample of ‘Emerald’. Three of these samples were from Texas and one of these samples was from Florida. Three of the four samples that were different from the reference cultivar were university samples. In addition, one sample, Empire11, was found to be an octoploid (2n = 8x = 80). For those samples that had a fingerprint different from the reference cultivar, contamination, selfing, and/or hybridization with other zoysiagrasses may have occurred.


Author(s):  
Mekuannet Belay Kebede ◽  
Degefa Gebissa

Genetic improvement in components of economic importance along with maintaining a sufficient amount of variability is always the desired objective in the any maize (Zea mays L.) breeding program which will be handled under the conditions of Haramaya, Eastern Ethiopia. Therefore, an experiment was conducted using (27) and (3) check/control varieties to determine the genetic variability of maize genotypes at Haramaya, eastern Ethiopia. The study results revealed that significantly the tallest plant heights for (PH) were recorded from (3) (170 cm) and (18) (167.5 cm) genotypes whereas the shortest PH were recorded from (13) (117.5 cm) and (23) genotypes (120 cm). Good plant aspects (PA) were obtained from genotype 12, 22 and 26 (PA-1.5) and poor PA were attained from genotype 1 (PA-2.5). Besides, genetic and phenotypic variances were estimated for seven components. The highest genotypic coefficients variation (GCV) and phenotypic coefficients of variation (PCV) were calculated from grain yield (GY – 23.39%). Comparatively the higher GY were attained from the genotypes of 3, 9 and 12. It can be concluded that almost all components of the PCV are greater than the GCV. Superior selected genotypes are recommended to the researchers /breeders to develop disease resistant and high yielder varieties to increase maize production by farmers under Haramaya and other similar agroecologies.


2021 ◽  
Vol 58 (2) ◽  
pp. 279-286
Author(s):  
Sandhani Saikia ◽  
Pratap Jyoti Handique ◽  
Mahendra K Modi

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.


2020 ◽  
Vol 49 (6) ◽  
pp. 1083-1092
Author(s):  
S Goitom ◽  
M.G. Gicheha ◽  
F.K. Njonge ◽  
N Kiplangat

Indigenous cattle play a vital role in subsistence and livelihood of pastoral producers in Eritrea. In order to optimally utilize and conserve these valuable indigenous cattle genetic resources, the need to carry out an inventory of their genetic diversity was recognized. This study assessed the genetic variability, population structure and admixture of the indigenous cattle populations (ICPs) of Eritrea using a genotype by sequencing (GBS) approach. The authors genotyped 188 animals, which were sampled from 27 cattle populations in three diverse agro-ecological zones (western lowlands, highlands and eastern lowlands). The genome-wide analysis results from this study revealed genetic diversity, population structure and admixture among the ICPs. Averages of the minor allele frequency (AF), observed heterozygosity (HO), expected heterozygosity (HE), and inbreeding coefficient (FIS) were 0.157, 0.255, 0.218, and -0.089, respectively. Nei’s genetic distance (Ds) between populations ranged from 0.24 to 0.27. Mean population differentiation (FST) ranged from 0.01 to 0.30. Analysis of molecular variance revealed high genetic variation between the populations. Principal component analysis and the distance-based unweighted pair group method and arithmetic mean analyses revealed weak substructure among the populations, separating them into three genetic clusters. However, multi-locus clustering had the lowest cross-validation error when two genetically distinct groups were modelled. This information about genetic diversity and population structure of Eritrean ICPs provided a basis for establishing their conservation and genetic improvement programmes. Keywords: genetic variability, molecular characterization, population differentiation


2011 ◽  
Vol 11 (spe) ◽  
pp. 16-26 ◽  
Author(s):  
Luiz Antônio dos Santos Dias

The paper analyses the puzzle of the food-energy-environmental security interaction, to which biofuels are part of the solution. It presents and discusses the contribution of genetic improvement to biofuels, with regard to the production of raw materials (oil and ethanol-producing plant species) and designs perspectives, opportunities, risks and challenges, with a special focus on the Brazilian scene. Bioethanol is a consolidated biofuel owing largely to the sugarcane breeding programs. These programs released 111 sugarcane cultivars and were responsible for a 20.8 % gain in productivity of bioethanol (in m³ ha-1) between 2000 and 2009. The program of Brazilian biodiesel production, initiated in 2005, had an annual growth rate of 10 % and the country is already the world's fourth largest producer. However, the contribution of breeding to biodiesel production is still modest, due to the lack of specific improvement programs for oil.


2010 ◽  
Vol 45 (10) ◽  
pp. 1109-1116 ◽  
Author(s):  
Carlos Henrique Mendes Malhado ◽  
Paulo Luiz Souza Carneiro ◽  
Ana Claudia Mendes Malhado ◽  
Raimundo Martins Filho ◽  
Riccardo Bozzi ◽  
...  

The objective of this work was to evaluate the population structure and the genetic and phenotypic progress of Nelore cattle in Northern Brazil. Pedigree information concerning animals born between 1942 and 2006 were analyzed. Population structure was performed using the Endog program. Out of the 140,628 animals studied, 67.7, 14.52 and 3.18% had complete pedigree record of the first, second and third parental generation, respectively. Inbreeding and average relatedness coefficients were low: 0.2 and 0.13%, respectively. However, these parameters may have been underestimated, since information on pedigree was incomplete. The effective number of founders was 370 and the genetic contribution of 10, 50 and 448 most influent ancestors explained 13.2, 28 and 50% of the genetic variability in the population, respectively. The genetic variability for growth traits and population structure demonstrates high probability of increasing productivity through selective breeding. Moreover, management strategies to reduce the currently observed age at first calving and generation intervals are important for Nelore cattle genetic improvement.


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