Isozyme Genotypes Research Articles

Association of isozyme genotypes with agronomic and seed composition traits in soybean

Two crosses between Glycine max (L.) Merr. and G. soja Sieb. & Zucc. parents were used to study the association between isozyme marker loci and agronomic and seed composition traits in soybean. The parents possessed different alleles at six isozyme loci for Cross 1 (A80-244036 × PI 326581) and at eight isozyme loci for Cross 2 (A81-157007 × PI 342618A). A total of 480 BC2F4:6 lines from the two crosses was evaluated for 13 traits in two environments. Lines were grouped in locus classes from 0 to 5 according to the number of loci homozygous for the G. soja alleles that they possessed. Within each locus class, each isozyme genotype was represented by five random lines.

Classification of Japanese rice varieties into Indica and Japonica types by using isozyme genotypes.

Sixty Asian varieties (Oryza sativa L.) which had been classified into Indica and Japonica types based on diagnostic characters (OKA 1958), were investigated for the genotypes of 10 isozyme species including 17 Ioci (Fig. 1 and 2, Table 1, 2 and 4). Genotypic frequencies at 11 loci, Acp-1. Amp-2. Cat-1. Est-2, Mal-1, Pgd-1. Pgi-1. Pboi-2, Pgi-3. Pox-2 and Sdh-1 were significantly different between Indica and Japonica types (Table 5). Discriminant scores (D scores) for Indica and Japonica varieties were calculated for the above eleven loci. However, the alleles at Pgd-1 and Sdh-1 Ioci were not enough to discriminate between Indica and Japonica types. D score averaged over the nine loci excluding Pgd-1 and Sdh-1, appeared to be more useful than that based on the eleven loci (Table 7). Thus, the Asian varieties were classified by using D scores averaged over the nine loci (Fig. 3A). Japonica varieties except for one and Indica varieties classified by OKA (1958) showed D scores ranging from 0.12 to 0.30 and from 0.69 to 0.94, respectively. Only one Japonica variety showed D scores with a value of 0.6. Because the variety carried alleles frequently found in Japonica type varieties, only at Acp-1, Mal-1 and Pgi-1 and alleles frequently found in Indica type varieties at other six loci, it appeared to be a 'recombinant type' between Indica and Japonica varieties. Based on these results, varieties with D scores ranging from 0.0 to 0.4 and from 0.6 to 1.0 were confirmed to be Japonica and Indica types, respectively, and newly used Pgi-3 and Mal-1 were also confirmed to be useful for discriminating the varieties.

ScreeningPopulus deltoidesmarsh. selections by allozymes to assure species identity

The allelic constitution of 169 Populus deltoides Marsh, clones, selected in North America, was studied at 8 marker allozyme loci (Aco‐2, Mdh‐2, Pgi‐2, Pgm‐1, Pgm‐3, 6‐Pgd‐2, 6‐Pgd‐4 and 6‐Pgd‐5) coding for 5 enzyme systems in root tips. The enzymes were assayed by horizontal starch gel electrophoresis. An examination of the allozyme profiles revealed that twenty‐seven of these selections (16%) were misidentified as P. deltoides. Eighteen of the misidentified selections displayed isozyme genotypes and patterns typical of P. deltoides x P. higra L. hybrids (P. xcanadenis Moench) and the remaining nine selections typical of P. deltoides x P. balsamiferaL. (P. xjackii Sarg.). The results indicated a need for screening North American P. deltoides selections used for plantation, breeding, and biological studies to assure their accurate species identification. Allozyme markers can be of potential importance in detecting misidentified P. deltoides specimens and in ascertaining their correct species identity.

Indentification of Pyrus Species by Peroxidase Isozyme Phenotypes of Flower Buds.

Forty-one Pyrus species and cultivars were analyzed for peroxidase isozyme phenotypes by polyacrylamide gel electrophoresis. Five peroxidase isozyme phenotypes were specified for flower buds in Pyrus plants, and were consistent and repeatable. Intercultivar and interspecific polymorphism was not sufficient to permit reliable identification of every Pyrus plants examined. Bud sport could not be distinguished from the original cultivar. The genetic basis of polymorphism was unknown, being unable to compare the peroxidase isozyme genotype observed in a hybrid with that predicted on the basis of parental peroxidase isozyme genotype. Some of the local (Kanto Province) cultivars were specified by their peroxidase isozyme phenotypes.

Genetic structure of black spruce on two contrasting sites

Several hundred dominant and co-dominant individuals in two populations of black spruce, located within 2 km of each other and representing upland and lowland site types, were sampled and mapped. Multilocus isozyme genotypes were determined and the genetic organization of the two populations examined by means of nearest-neighbour analysis and spatial autocorrelation of alleles. On the upland site type, population density was much higher and variation in age considerably less than on the lowland site type, which was interpreted as evidence for fire origin in the former. On the upland site, the mature trees were more inbred, possibly due to the conditions under which regeneration occurred and because of weak selective pressure. On the lowland site, clustering of similar genotypes was detectable on a local scale but the mature trees were not inbred. The two populations were very similar in terms of allozyme frequencies.

Assessment of natural interspecific hybridization of blue and Engelmann spruce in southwestern Colorado

In a partial diallel mating design among 20 blue and 20 Engelmann spruce parents, the interspecific crosses were successful only with Engelmann spruce as the female parent. No viable seed were obtained from the reciprocal cross among the 60 full-sib families attempted. Under the conditions of artificial pollination and a controlled germination environment, an average of 0.3% of the seed germinated on a total seed basis across all 20 Engelmann spruce females. Many abnormalities were observed among the germinating hybrid seed, suggesting hybrid inviability also contributes to the low crossability between these two species. Isozyme analysis was used to confirm the interspecific hybrids between blue and Engelmann spruce based on the unique genotypic compositions of the hybrids relative to the two species. No natural F1 hybrids between blue and Engelmann spruce were observed in this study based on isozyme analysis of mature individuals or their seedling progeny. Analyses included samples of open-pollinated seed from blue and Engelmann spruce females located in an area where both species are present in close proximity, often side-by-side, and where pollen shed and female strobilus receptivity in the two species are coincident. In addition, there was evidence of possible gametic selection or hybrid inviability among the full-sib progeny based on deviations of observed from expected segregation ratios for progeny isozyme genotypes. Deviations tended to favor the allele more common to both species rather than the allele unique or more common to only one species. Also, the elevationally allopatric blue and Engelmann spruce subpopulations were less divergent genetically than the sympatric subpopulations.

Nonrandom Associations between Sex and 6-Phosphogluconate Dehydrogenase Isozyme Genotypes in Gleditsia triacanthos L.

Journal Article Nonrandom Associations between Sex and 6-Phosphogluconate Dehydrogenase Isozyme Genotypes in Gleditsia triacanthos L. Get access A. Schnabel, A. Schnabel Department of Genetics, University of GeorgiaAthens Address reprint requests to Dr. Schnabel, Department of Genetics, University of Georgia, Athens, GA 30602. Search for other works by this author on: Oxford Academic PubMed Google Scholar J. L. Hamrick J. L. Hamrick Department of Genetics, University of GeorgiaAthens Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 81, Issue 3, May 1990, Pages 230–233, https://doi.org/10.1093/oxfordjournals.jhered.a110979 Published: 01 May 1990

Investigation on the isozyme genotype and KClO3 resistance of seedlings in African deep water rice, Oryza glaberrima Steudel.

Investigation on the isozyme genotype and KClO3 resistance of seedlings in African deep water rice, Oryza glaberrima Steudel.

Distorted segregation of the esterase isozyme genotypes in barley (Hordeum vulgare L.).

Distorted segregation of the esterase isozyme genotypes was observed in F2 population which was produced from a cross combination between 'Ko A' and 'Mokusekko 3' of barley varieties. After examining the segregation of esterase isozyme genotypes in B1F1 hybrids derived from the reciprocal backcrosses, it was made clear that the distorted segregation was caused by certation between pollens of different genotypes, independent of the female genotypes. Furthermore, the certation was controlled by a newly designated gene, Ga2, at the locus which was linked with the multiocus, Est1, Est2 and Est4, for esterase isozymes at the long arm of chromosome 3. The distorted segregation ratios did not significantly vary among F2 populations derived from F1 hybrids of the same combination which were grown in different years. Mechanically mixed pollens of the parents, however, could not induce the certation.

Genetic studies on the Pacific abalone. XX. Induction of gynogenetic diploid by inhibiting second meiosis in the Pacific abalone.

Successful inductions of gynogenesis and of the two kinds of triploid animals of the Pacific abalone Haliotis discus hannai have been reported. After careful re-examination of various con-ditions developed before, selected were irradiation of spermatozoa by ultraviolet ray of a total dose of 1, 200erg/mm2 for genetic inactivation of paternal genomes and cold shock of zygote at 3°C for 15min, starting 32min after fertilization for retention of second polar body. A set of such treatments resulted in low survival rates of both planktonic and settled larvae but appreciable numbers of viable gynogenetic diploid, indicating 50 to 60 percentage induction of gynogenetic di-ploid among the animals survived. Simultaneous induction of some aneuploid animals was observ-ed through the analyses of isozyme genotypes. Comparison of the shell-length distributions be-tween the sib animals demonstrated that gynogenetic diploid animals revealed enlarged variances and marked deviations in mean values towards either bigger or smaller direction in comparison with those of normal diploid animals.

Identification and investigation of relationships of mandarin types using isozyme analysis

Sixteen enzyme systems with 19 loci were used to discriminate 19 mandarin cultivars and hybrids. Variability was observed at 12 loci, and all but 3 mandarin types could be discriminated, 2 of which were probably identical. Relatedness within the tangelo and tangor groups was high, probably reflecting their recent origin. Relatedness within the common mandarin group was low, reflecting their multiple origins and long cultivation. Exceptions were cultivars ‘Algerian’ and ‘Beauty of Glen Retreat’, which differed at only 1 locus. Relatedness between the groups was generally low, with the least relatedness between the tangelos and the other groups, probably owing to their grapefruit parent. The ‘Ellendale’ cultivars formed a particularly cohesive group, but with 2 isozyme genotypes, differing at 2 loci, both marketed as ‘Ellendale’. Three of the ‘Ellendale’-type cultivars probably arose by self-pollination of ‘Ellendale’, the rest either by self-pollination or by mutation.

Relation of Isozyme Genotypes to Quantitative Characters in Soybean

Selection based on genotypes at marker loci may increase the efficiency of plant improvement. Two interspecific crosses of soybean [Glycine max (L.) Merr ✕ G. soja Sieb. & Zucc.] were used to examine the relationships between isozyme marker loci and agronomic traits. The parents had different alleles at six isozyme loci for Cross 1 (A80‐244036 ✕ PI 326581) and eight isozyme loci for Cross 2 (A81‐157007 ✕ PI 342618A). Approximately 4000 BC2F4‐derived lines were evaluated in two replications at two locations for maturity (MAT), height (HT), lodging (LDG), plant type (PLT) and vining (VNG). Lines were identified that were homozygous for G. soja alleles at different numbers of marker loci, from 0 to 5. Within each locus class, there were a number of specific enzyme genotypes, and each enzyme genotype was represented by a number of lines from different BC2F1 families. Associations were observed for specific enzyme genotypes and every quantitative trait in both crosses, but the particular isozyme genotype/quantitative trait relationships were population specific. No complete or very tight linkages between marker loci and loci affecting quantitative traits were identified in this study, but such linkages would be useful in the identification and isolation of genes affecting the expression of quantitative traits. For every trait except MAT, an increase in the numbers of isozyme marker loci that were homozygous for alleles from G. soja resulted in a change in the phenotype toward the G. soja parent in both crosses. The relationship between numbers of homozygous marker loci and parental phenotype could increase the efficiency of an introgression program by hastening recovery of the recurrent parent phenotype while maintaining specific desired alleles from the donor parent.

Linkage relationship between two loci for the barley yellow mosaic resistance of Mokusekko 3 and esterase isozymes in barley (Hordeum vulgare L.).

A Chinese landrace of six-rowed barley, Mokusekko 3, has been successfully utllized for introducing its BaYMV resistant gene, Ym, to Japanese malting two-rowed barley. However, information about the location of the Ym locus on a chromosome is limited. The authors almed to confirm the linkage relationship between the Ym locus and complex loci for esterase isozymes, as most of the strains into which the BaYMV resistance from Mokusekko 3 had been introduced showed the same esterase isozyme banding pattern as that of the resistant parent. The linkage analyses revealed that the Ym locus is tightly linked with the complex loci (Est1-Est2-Est4) for the esterase isozymes which are located at the terminal of the long arm of chromosome 3, and that the recombination values ranged from 1.26 to 5.01%. Based on these results, it is concluded that the BaYMV resistant individuals and strains carrying the Ym gene can be easily obtained by selecting the seedlings which show the same banding pattern of esterase isozyme genotype as that of Mokusekko 3, by means of starch gel electrophoresis.

Identification of Pineapple Cultivars by Isozyme Genotypes

Abstract Starch gel electrophoresis of leaf tissue samples was used to distinguish pineapple [Ananas comosus (L.) Merr.] cultivars. Isozyme genotypes at two peroxidase and three phosphoglucomutase loci allowed the unique identification of 15 of the 27 cultivars examined. The hypotheses that some cultivars originated as either sports or hybrids were confirmed by the allozyme data.

The Effect of Isozyme Selection on Yield and Flowering Time in Lolium perenne

AbstractA series of lines, differing in isozyme genotype, were constructed by selection from within three cultivars of Lolium perenne. Field assessment of the progeny of these selected line? revealed variation in yield and timing of inflorescence emergence. This variation between lines from within a cultivar could not be accounted for by the differing levels of homozygosity attained. In some instances differences in yield were associated with homozygosity for specific alleles at the PGI/2 locus, background genotype was however, of major importance. The variation identified could be attributable to founder effects or possible linkage of quantitative trail loci to the PGI/2 locus.

The origin of cornbelt maize: The isozyme evidence

Historical records show t hat the Midwestern dent corns of the United States originated from hybridization of two landraces, Northern Flint and Southern Dent. We examined the origin of Southern and Midwestern Dents by means of isozyme electrophoresis. Isozyme genotypes were determined for 23 loci in 12 plants each of 32 accessions of Southern Dent. Previously published isozyme data for maize landraces of Mexico and North America and for U.S. Midwestern Dents were included for comparative purposes. The data show that Northern Flint and Southern Dent are among the isozymically most divergent maize landraces. Nei’s genetic identities between populations of these two landraces are very low for conspecific populations (ca. 0.80). Southern Dent of the southeastern U.S. appears closely related to similar dent corns of southern Mexico, supporting a previously published hypothesis that U.S. Southern Dent is largely derived from the dent corns of southern Mexico. The Midwestern Dents, which resulted from crosses of Southern Dent and Northern Flint, are much more like Southern Dent than Northern Flint in their isozyme profile. Similarly, public inbreds show greater affinity to Southern Dent with the exception of sweet corn lines, which resemble Northern Flint in their isozyme allele frequencies. North American public inbreds do not contain appreciable isozymic variation beyond that found in Northern Flint and Southern Dent.

Differential fitness of allelic isozymes in the marine gastropodsLittorina punctata andLittorina neritoides, exposed to the environmental stress of the combined effects of cadmium and mercury pollution

The present study tested the separate and the interactive pollution effects of cadmium and mercury on the electrophoretically detected allelic isozyme frequencies of the enzyme phosphoglucose isomerase for two species of littoral marine gastropods —Littorina punctata andL. neritoides — and the enzyme amino peptidase forL. neritoides. Our results indicate differential survivorship of allelic isozyme genotypes specific for each type of pollutant and for their interaction, as well as trends common to all pollutants. Theoretically the results reflect the adaptive nature of at least some allozymic genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Practically, the results reinforce earlier conclusions that changes in the frequency of allelic isozymes may be used as a genetic monitor of pollution.

Testing the Efficiency of Pollination Bag Materials

AbstractCrossing bags manufactured from three grades of polyester and three types of paper bags were tested for their permeability to grass pollen. Bags were placed on L. perenne plants of known PGI isozyme genotype. Any pollen passing through the crossing bag and pollinating the plant was detected by assaying its progeny for PGI isozymes. The results obtained allowed differentiation of the various materials for their suitability for pollen proofing.

Variation of esterase isozyme genotypes in a pedigree of Japanese two-rowed barley.

In Japanese two-rowed barley varieties, there are 4 genotypes for esterase isozymes at 3 loci (Est1' Est2 and Est4) which are closely linked as a gene block at the terminal of the long arm of chromosome 3. The genotypes are Pr-Fr-Su, Ca-Dr-Nz, Ca-Fr-Su and Ca-Fr-At which consist of different allelic c.ombinations at 3 loci, Est1-Est2-Est4, respectively, and most of the varieties have either Pr-Fr-Su or Ca-Dr-Nz genotype. While the varieties which are old or introduced ones in the early 20 century, for instance, Golden Melon, have mainly the Ca-Dr-Nz genotype, the Pr-Fr-Su genotypes are frequently found in improved varieties. Thus, the varieties with the Pr-Fr-Su genotype which was derived from Prior occupy the major acreage of two-rowed barley cultivation at present (Figs. 2 and 3).

Isozyme Variability and Breeding Systems in Populations of Yellow Nutsedge (Cyperus esculentus)

The importance of seeds in the reproduction and maintenance of yellow nutsedge (Cyperus esculentusL. # CYPES) populations was evaluated. Isozyme analysis using starch gel electrophoresis was performed on 20 individuals of each of 10 widely separate populations in California. Genetic variation among individuals served as an indicator of the relative importance of asexual and sexual reproduction in each population. Eight enzyme systems were assayed from which 12 loci were resolvable, with four of those loci exhibiting variability. A maximum of four isozyme genotypes appeared in any population; only nine of 81 total potential genotypes were identified. Five populations were isozymically uniform, apparently composed of a single genotype. The remaining five populations were genotypically variable; these frequently deviated strongly from the genotype frequencies expected of a sexually reproducing population. These results indicate that sexually produced seeds are unimportant in the maintenance of yellow nutsedge populations in agricultural environments. Although viable seed may be produced, tubers appear to be the primary mode of reproduction in this species.