Conservation of genetic diversity in regenerated landraces of Italian ryegrass

2011 ◽  
Vol 10 (1) ◽  
pp. 5-13 ◽  
Author(s):  
J. E. López ◽  
J. A. Oliveira
Keyword(s):  
Genetic Diversity ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Starch Gel Electrophoresis ◽  
Shikimate Dehydrogenase ◽  
Sheltered Site ◽  
Starch Gel ◽  
Seed Regeneration ◽  
The Mean ◽  
Regeneration Effect

The objective of this study was to investigate the effect of one cycle of seed regeneration on the conservation of genetic diversity in five Italian ryegrass landraces (Lolium multiflorum Lam.). Regeneration took place outdoors, in a sheltered site surrounded by tall Galician wheat, 20 m from the nearest source of alien pollen. A balanced mixture of seed (the same weight of seed per plant) was made from 90–100 plants harvested within each population. The conservation of allele frequencies was assessed by starch gel electrophoresis. Five enzyme systems from 78–153 plants per population were examined on slices of a single histidine–citrate starch gel. Each regenerated population differed from its original landrace in at least one of the five loci. The mean heterozygosity per locus was 0.45 for original and regenerated populations, and the mean number of alleles per locus was 3.7 and 3.6 for original and regenerated populations, respectively. There was no loss of common alleles (frequency >0.05) in the five regenerated populations compared with the original populations. Only three rare alleles (frequency < 0.05) were lost (e.g. alleles phosphoglucose isomerase (PGI)-2a, PGI-2c* and shikimate dehydrogenase (SDH)-1d in Padrón, Pravia and Luarca, respectively). No regeneration effect (P>0.05) was observed in the six agromorphological characters. However, a significant landrace effect was observed (P < 0.05) in the five agromorphological traits and the regenerated landraces deviated from the original landraces in 20% of direct comparisons. The results suggest that the method of regeneration used was not very suitable for maintaining the genetic integrity of the original landraces.

Genetic variation in 26 populations of Racospermaauriculiforme and Racospermamangium using allozymes

1994 ◽  
Vol 24 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
P.D. Khasa ◽  
W.M. Cheliak ◽  
J. Bousquet
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Unknown Origin ◽  
Population Level ◽  
Genetic Distances ◽  
Starch Gel Electrophoresis ◽  
Introduced Populations ◽  
Linear Relationships ◽  
Starch Gel ◽  
The Mean

Racospermaauriculiforme (Cunn. ex Benth.) Pedley and Racospermamangium (Willd.) Pedley are two fast-growing multipurpose leguminous species that have great potential for reforestation in the subhumid and humid tropics. The level and distribution of genetic variability were evaluated among and within 13 populations of each species at 18 loci encoding 10 enzymes, using starch gel electrophoresis. At the population level, the mean number of alleles per locus, the mean percentage of polymorphic loci, and mean expected heterozygosity were, respectively, 1.9, 52.1%, and 0.122 for R. auriculiforme, and 1.5, 24.3%, and 0.064 for R. mangium. Therefore, R. mangium appeared genetically depauperate compared with R. auriculiforme. The proportion of the total genetic diversity that resided among populations in R. auriculiforme (18%) was twice that in R. mangium (9%). No linear relationships were detected between genetic and geographic distances among populations. Cluster analysis of Nei's genetic distances and discriminant analysis did not show any significant geographic pattern of population differentiation for R. mangium. These same analyses revealed two distinct clusters of populations for R. auriculiforme, one in Queensland, Australia, and Papua New Guinea, and the other in the Northern Territory of Australia and Indonesia. For both taxa, seed of unknown origin of some introduced populations in Zaire and Congo could be identified. The genetic distance between the two species (D = 0.097) was, as expected, much larger than the average intraspecific genetic distance derived from comparisons of conspecific populations (D = 0.034 for R. auriculiforme and D = 0.007 for R. mangium). However, the amplitude of the interspecific genetic distance calculated is representative of divergence levels usually observed among subspecific taxa. Based on this, and the lower levels of genetic diversity found in R. mangium, it is suggested that R. mangium derived recently from R. auriculiforme.

Genetic diversity in red pine: evidence for low genic heterozygosity

1977 ◽  
Vol 7 (2) ◽  
pp. 343-347 ◽  
Author(s):  
D. P. Fowler ◽  
R. W. Morris
Keyword(s):  
Genetic Diversity ◽  
Gel Electrophoresis ◽  
Allozyme Variation ◽  
Red Pine ◽  
Starch Gel Electrophoresis ◽  
Banding Patterns ◽  
Coniferous Species ◽  
Low Degree ◽  
Starch Gel ◽  
Genetically Determined

Starch gel electrophoresis was used to survey for genetically determined enzyme mobility differences among 297 megagametophytes of red pine (Pinusresinosa Ait.) from five widely separated geographical sources. Consistent and reproducible enzyme banding patterns were observed with five of the seven isozyme systems assayed. No variation in band mobility was observed in any of these systems. This result stands in contrast with those reported from surveys of allozyme variation in other coniferous species but is consistent with the low degree of genetic variation observed in red pine for higher levels of genetic organization. It is concluded that red pine is genetically depauperate.Possible explanations for restricted genetic diversity are discussed. The most plausible explanation suggests that red pine was at sometime, possibly during the Pleistocene, reduced to a small refugial population and has yet to reestablish equilibrium heterozygosity.

Genetic variation in populations of the endemic Achillea millefolium ssp. megacephala from the Athabasca sand dunes and the widespread ssp. lanulosa in western North America

1996 ◽  
Vol 74 (7) ◽  
pp. 1138-1146 ◽  
Author(s):  
Brett G. Purdy ◽  
Randall J. Bayer
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Diversity ◽  
Sand Dunes ◽  
Achillea Millefolium ◽  
Starch Gel Electrophoresis ◽  
Widespread Species ◽  
Polymorphic Loci ◽  
Endemic Taxon ◽  
Starch Gel

As part of an analysis of genetic diversity in endemic taxa of the Athabasca sand dunes in northern Saskatchewan, Canada, genetic variation was examined by starch gel electrophoresis in six populations of the endemic Achillea millefolium ssp. megacephala, and 13 populations of the closely related widespread taxon, A. millefolium ssp. lanulosa. Endemic populations had more alleles per locus, a higher percentage of polymorphic loci, and greater genetic diversity than did populations of the widespread taxon. At polymorphic loci, total gene diversity was comparable in both taxa, although within-population gene diversity was higher in the endemic taxon. Population differentiation (GST) was considerably lower in ssp. megacephala than in ssp. lanulosa, although GST values were reduced when the parameter was calculated separately for geographic subdivisions of the widespread taxon. Our results differ from previous studies in which the endemic is typically depauperate of genetic variation relative to related widespread species. We suggest that obligate sexual reproduction and the absence of long-term asexual reproduction may be one of a number of factors that help populations of ssp. megacephala maintain higher levels of genetic variation on the Athabasca sand dunes. Keywords: genetic variation, endemic, rare species, Athabasca sand dunes, Achillea millefolium.

scholarly journals Estructura genética de poblaciones de Eriocaulon bilobatum (Eriocaulaceae): una especie amenazada de humedades temporales

2019 ◽  
Vol 85 ◽  
pp. 81
Author(s):  
Fabiola Magallán Hernández ◽  
Mahinda Martínez ◽  
Luis Hernández Sandoval ◽  
Ken Oyama
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Genetic Structure ◽  
Gel Electrophoresis ◽  
Life History Traits ◽  
Aquatic Environments ◽  
Starch Gel Electrophoresis ◽  
Temporary Wetlands ◽  
Sexual And Asexual Reproduction ◽  
Starch Gel

<em>Eriocaulon bilobatum</em> is an aquatic species that inhabits temporary wetlands in central Mexico. It is annual, herbaceous, emergent, with sexual and asexual reproduction, monoecious and insect pollinated. It is a rare and vulnerable species due to its endangered habitats. The objectives of this study were to determine the diversity and genetic structure of <em>E. bilobatum </em> and to know if there is a correlation with genetic diversity and its ecological and life history traits. Using horizontal starch-gel electrophoresis, we screened 160 individuals from four populations. <em>E. bilobatum</em> has a higher genetic diversity (A=2.32, Ae=1.31, P=69.65, Ho=0.134, He=0.197, HT=0.221) than species with similar ecological and life history traits, moderate levels of inbreeding (FIS = 0.312) and low genetic differentiation among populations (FST = 0.053 y GST = 0.048). Its diversity and genetic structure are determined by the mating system and life history traits, more than by inhabiting aquatic environments.

scholarly journals Identifying Crabapple Cultivars by Isozymes

1995 ◽  
Vol 120 (5) ◽  
pp. 706-709 ◽  
Author(s):  
Robert D. Marquard ◽  
Charlotte R. Chan
Keyword(s):  
Alcohol Dehydrogenase ◽  
Gel Electrophoresis ◽  
Cultivar Identification ◽  
Enzyme System ◽  
Starch Gel Electrophoresis ◽  
Shikimate Dehydrogenase ◽  
Polymorphic Region ◽  
Banding Patterns ◽  
Phosphogluconate Dehydrogenase ◽  
Starch Gel

Forty-five crabapple (Malus spp.) cultivars were evaluated for 16 isozyme systems by starch gel electrophoresis. Of the 16 systems evaluated, 6 were useful in separating among cultivars. Enzyme systems used to distinguish among the cultivars included alcohol dehydrogenase, aspartate aminotransferase, malate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucoisomerase, and shikimate dehydrogenase. Each enzyme system produced one well-resolved polymorphic region except for 6-phosphogluconate dehydrogenase, which produced two. Most crabapple selections could be identified when all six enzymes were evaluated. Alcohol dehydrogenase had the most diagnostic banding patterns useful for cultivar identification.

Herbage production and tiller density in five related grasses, their hybrids and mixtures

1996 ◽  
Vol 127 (1) ◽  
pp. 57-65 ◽  
Author(s):  
D. Wilman ◽  
Y. Gao
Keyword(s):  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Meadow Fescue ◽  
The Mean ◽  
Tiller Density ◽  
Better Than

SUMMARYFour grass species, three hybrids and three mixtures were grown in field swards near Aberystwyth. All swards were amply supplied with nutrients and were cut at 5-week intervals during the year of sowing (1989) and during the following 4 years. The order of the grasses in rate of establishment was: Westerwolds ryegrass > Italian ryegrass (Lolium multiflorum) > Italian ryegrass × perennial ryegrass, Italian ryegrass × meadow fescue, perennial ryegrass (Lolium perenne) > perennial ryegrass × meadow fescue, meadow fescue (Festuca pratensis) > tall fescue (Festuca arundinacea). During the sowing year as a whole, Italian ryegrass was the highest yielding grass, followed by Westerwolds ryegrass. During the remaining period (1990–93), as a whole, the highest yields were obtained from perennial ryegrass sown alone or in a mixture with tall fescue. Tall fescue sown alone was one of the lowest yielding grasses in the year of sowing, but developed to be the highest yielding in 1992 and 1993. Westerwolds ryegrass persisted least well, although some plants did survive until 1992. Italian ryegrass persisted better than Westerwolds and Italian ryegrass × meadow fescue persisted better than Italian ryegrass. Hybrid ryegrass and perennial ryegrass × meadow fescue persisted satisfactorily but with fewer tillers/m2 than perennial ryegrass or tall fescue. The yield of tall fescue in March was as high as that of Italian ryegrass in 1990 and 1991 and higher than that of any of the other grasses in 1992 and 1993; the tiller density of tall fescue was particularly high in March. The yield of mixtures (Italian ryegrass with perennial ryegrass, Italian ryegrass with tall fescue and perennial ryegrass with tall fescue) was, on average, 2·5% more than the mean of the component species when sown alone. When grown with ryegrass, tall fescue was not prominent initially but its proportion in the sward gradually increased.

β-Globulin polymorphism and economic factors in dairy cattle

1960 ◽  
Vol 54 (3) ◽  
pp. 321-328 ◽  
Author(s):  
G. C. Ashton
Keyword(s):  
Normal Distribution ◽  
Milk Yield ◽  
Standard Error ◽  
Great Majority ◽  
Starch Gel Electrophoresis ◽  
Normal Distribution Curve ◽  
Starch Gel ◽  
The Mean ◽  
Milk Marketing ◽  
Genetic Value

1. The serum β-globulin phenotype of 141 bulls located at Cattle Breeding Centres in England and Wales was determined by starch-gel electrophoresis.2. The distribution of the contemporary comparison values of these bulls with respect to β-globulin type was investigated. The great majority of the bulls were βAA, βAD, or βDD with very few βAE and βDE and no βEE types.3. The contemporary comparison values for 130 bulls of the three types βAA, βAD and βDD each fell into a normal distribution. The mean and its standard error and the standard deviation of the mean and its standard error were calculated for each of the three curves. The mean contemporary comparison value for the βAA bulls was + 12·2 ± 5·4 gal., for the βAD bulls + 26·8 ± 5·4 gal., and for the βDD bulls + 38·2 ± 5·5 gal. The βAA and βDD means were significantly different (P < 0·01).4. The pooled contemporary comparison values of the βAA, βAD and βDD bulls did not give a normal distribution curve, neither did the contemporary comparison values for a sample of 1028 bulls quoted by the Milk Marketing Board. However, when the contemporary comparison values of the βAA, βAD and βDD groups were superimposed around the same mean, the ensuing distribution was normal.5. It is concluded that the β-globulin locus is concerned in the genetic control of milk yield. The estimated mean genetic value of βD over βA is approximately + 50 gal. This is about one-sixth of the total genetic variation in milk yield in the major milk breeds.6. The distribution of butterfat percentages with respect to β-globulin phenotype in four Ayrshire and one Friesian herds was investigated. No difference between the mean first lactation butterfat percentage of the βAA, βAD, and βDD cows in each herd was found. There was an indication (not significant) that the mean butterfat percentage of the βAE and βDE cows in three of the four Ayrshire herds studied was higher than the mean of the other groups.

Genetic Variation in Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 506-512 ◽  
Author(s):  
Michael J. Horak ◽  
Jodie S. Holt ◽  
Norman C. Ellstrand
Keyword(s):  
Genetic Diversity ◽  
Genotypic Diversity ◽  
Genetic Distances ◽  
Cyperus Rotundus ◽  
Starch Gel Electrophoresis ◽  
Cyperus Esculentus ◽  
Purple Nutsedge ◽  
Yellow Nutsedge ◽  
Low Genetic Diversity ◽  
Starch Gel

Genetic diversity within and among populations of yellow nutsedge (Cyperus esculentusL. # CYPES) was analyzed to evaluate and quantify the genetic consequences of the reported predominance of asexually-produced tubers as colonizing agents. Ten populations were examined using starch gel electrophoresis for allozyme analysis. Four populations of purple nutsedge (Cyperus rotundusL. # CYPRO) were surveyed for comparison. Twelve loci were identified in yellow nutsedge among the eight enzyme systems examined; ten of these loci were found in purple nutsedge. Yellow nutsedge showed relatively low genetic diversity. Most of the genetic diversity occurred as differences among individuals within populations (Hs), compared to differences among populations (Dst) for the four variable loci identified in this species. Thus, most genetic distancesbetween its populations were small. Generally, only a few genotypes occurred within each population. Purple nutsedge was found to possess even lower within- and among-population gene and genotypic diversity. This study supports the view that tubers account for most of the establishment of new populations of both species.

The systematic status of the lagoon periwinkle, Littorina tenebrosa

1999 ◽  
Vol 79 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Iain F. Wilson ◽  
Elizabeth M. Gosling ◽  
William Tapper
Keyword(s):  
Phylogenetic Analysis ◽  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Distance ◽  
Gel Electrophoresis ◽  
Distinct Group ◽  
Starch Gel Electrophoresis ◽  
Allopatric Populations ◽  
Starch Gel ◽  
The Mean

Eight samples of Littorina tenebrosa and L. saxatilis (Mollusca: Gastropoda) from Ireland and Britain, including pairs of each form from two locations in Ireland, were screened for genetic variation at 12 polymorphic enzyme loci using starch gel electrophoresis. Levels of polymorphism and heterozygosity were similar in L. tenebrosa and L. saxatilis, apart from a sample of L. tenebrosa from Britain which was less polymorphic than the Irish samples. No alleles were found to be unique to either form. Phylogenetic analysis using UPGMA showed that L. saxatilis and L. tenebrosa populations clustered as a monophyletic group. Nevertheless, the mean genetic distance between parapatric populations of L. saxatilis and L. tenebrosa (D=0.076) was similar to the mean for allopatric populations of either species (D=0.080). This indicates that there is a barrier to gene flow between the two forms Despite this, L. tenebrosa does not merit specific status since populations of this snail do not cluster as a distinct group, separate from L. saxatilis populations.

EFFECTS OF RATES OF N AND REGROWTH INTERVALS ON YIELDS AND QUALITY OF ITALIAN RYEGRASS GROWN AS A SUMMER ANNUAL

1978 ◽  
Vol 58 (3) ◽  
pp. 691-697 ◽  
Author(s):  
H. T. KUNELIUS ◽  
F. W. CALDER
Keyword(s):  
Dry Matter ◽  
Sandy Loam ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Total N ◽  
Harvest Intervals ◽  
The Mean ◽  
Suitable System

Italian ryegrass (IRG) (Lolium multiflorum Lam. cv. Lemtal) was grown on a sandy loam and/or on a fine sandy loam in 1974, 1975, and 1976. IRG was fertilized three times each year with 40, 80, or 120 kg N/ha/application and harvested at 3-, 4-, 5- or 6-wk intervals starting in July. Dry matter (DM) yield increased with the rate of applied N. Four-week harvest intervals generally resulted in the greatest DM yields ranging from 4.32 to 7.11 t/ha. Droughty conditions in 1975 reduced the growth and resulted in small DM yields particularly on sandy loam. The mean total N concentrations of IRG ranged from 2.40 to 3.68% and was approximately proportional to applied N. Longer regrowth intervals decreased total N concentrations by. 12–.56% units per week. Applied N did not influence the in vitro disappearance of DM (IVDDM), whereas longer regrowth intervals reduced IVDDM in 1975. The harvest system with a 4-wk regrowth interval and 80 kg N/ha/apphcation resulted in satisfactory DM, N, and digestible DM yields and appeared to be a suitable system for IRG grown as a summer annual.

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