Expression of Introduced Genes after Tuber Propagation of Transgenic Potato Plants

The linkage relationship between eighteen isozyme loci and the morphological markers hypocotyl colour (R-r), monogerm character (M-m), pollen fertility (X) and stem fasciation (Verb.) are tested. Three linkage groups could be set up, involving all morphological marker loci and eight of the isozyme loci. Est-2, R-r, Fdp-2, Got2 and Icd-1 belong to linkage group I, linkage group II includes the loci Fas-fas M-m, Est-3 and Aco-1, linkage group III contains the loci X, Mdh-1 and Est-5. When analysing the inheritance of isozymes and RFLPs, deviations are usually found in some lines from the expected frequencies of a 3 : 1 or 1 : 2 : 1 segregation at single marker loci. In many cases these data can still be used for the estimation of recombination values with linked loci under the control of selection. Procedures to estimate linkage in such cases are given and applied to experimental data in Beta vulgaris.     

New Isozyme Markers in Vicia faba: Inheritance and Linkage

Results on the inheritance of 6 enzyme systems: LDH, PGM, FDH, SKD, SOD, AAT from seeds of Vicia faba and the linkage relationships among these isozyme loci are presented. The allozymes at each one of these loci behaved in a codominant manner and segregated in the expected Mendelian ratio. Linkage tests between these loci showed that they segregate independently.     

Inheritance of isozymes in peach x Prunus kansuensis and peach x Prunus davidiana hybrids

Summary Isozyme variation and inheritance were investigated with starch gel electrophoresis in peach (Prunus persica L. Batsch) x P. kansuensis Rehd. and peach x P. davidiana (Carr.) Franch. interspecific hybrids. Of five enzyme systems surveyed for polymorphism, four systems were identified as polymorphic [isocitrate dehydrogenase (IDH, EC 1.1.1.41), phosphoglucomutase (PGM, EC 2.7.5.1), aspartate aminotransferase (AAT, EC 2.6.1.1), and 6 phosphogluconate dehydrogenase (PGD, EC 1.1.1.44)] and may be useful as genetic markers in future cultivar and rootstock development. Analysis of progenies segregating for pairs of loci suggests a possible linkage between the loci coding for Aat-1 and Pgd-2. Independent assortment was observed for isozyme loci Idh/Pgm-2, Idh/Aat-1, Idh/Pgd-2, Pgm-2/Aat-1, Pgm-2/Pgd-2, and Aat-2/Aat-1. The red leaf locus, Gr, assorted independently of the isozyme loci: Idh, Pgm-2, Aat-1, and Pgd-2.     

Inheritance and linkage study of isozyme loci and morphological traits in red clover

Information on inheritance of isozymes and linkage maps in Trifolium pratense L is limited. Genetic analysis of 18 isozyme systems and three morphological traits (white vs. pink flower, present vs. absent leaf marker and green vs. sun-red stem) was conducted. Six loci of four isozymes had simple Mendelian inheritance. Joint segregation analyses among 8 isozyme loci and 3 morphological gene markers (55 pair-wise combinations) resulted in the assignment of one linkage group. Two morphological markers coding for flower (c) and stem (gs) color were found to be in the same linkage group based on the analyses of two segregating families. The recombination values of the two progenies for c-gs were 0.079 and 0.113. No linkage was found between any of the isozyme loci and the morphological traits. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic Analysis of DIA, GOT and PGI Isozyme Loci in Daucus carota L. ssp. sativas

Isozymes are useful biochemical markers in plant breeding. This paper presents the first results on the inheritance of three enzyme systems: diaphorase (DIA), glutamate oxalacetate transaminase (GOT) and phosphoglucoisomerase (PGI) from leaves of Daucus carota L. ssp. sativus and the linkage relationships among these isozyme loci, marked Dia, Got, and Pgi. Methods of extraction and electrophoresis are described. Segregation ratios indicated that the DIA system is controlled by three genes: Dia-1, Dia-2 and Dia-3, Dia-1 as invariant. Two codominant alleles and a null allele were found for Dia-2, and four codominant alleles for Dia-3-GOT isozymes are encoded by three genes; Got-1, Got-2 and Got-3. An active allele and a null allele were observed for Got-1, two codominant alleles for Got-2 and Got-3, respectively. PGI isozymes are controlled by a single gene, Pgi-1, with two codominant alleles. Altogether one invariant isozyme locus and six polymorphic loci are postulated. Test of joint segregation suggested a linkage of Dia-3 and Pgi-1. The recombination value is 0.04 ± 0.009.     

Genetic and linkage analysis of isozyme loci in Daucus carota L.

Summary Electrophoretic polymorphisms of eight enzyme systems were studied in leaves of Daucus carota ssp. sativus in order to identify additional isozyme loci and generate first linkage groups of genetic markers. The genetic analysis of aconitase (ACO), leucin aminopeptidase (LAP), menadione reductase (MDR), phosphoglucomutase (PGM), 6-phosphogluconic dehydrogenase (6-PGD), shikimate dehydrogenase (SKD), and triose phosphate isomerase (TPI) zymograms resulted in the identification of 8 isozyme marker loci, designated as Aco-1, Lap-1, Pgm-1, Pgm-3, 6-Pgd-2, Skd-1, Tpi-1, and Tpi-2. All loci segregated with codominant alleles and encoded for monomers (ACO, LAP, PGM, SKD), and dimers (6-PGD, TPI), respectively. MDR enzymes of the variable region MDR-2 appeared to be identical with Dia-2 isozymes. Tests of joint segregation for pairwise comparisons of all 14 isozyme marker loci now available in carrots indicate that 12 loci are linked in 4 linkage groups (marked K1 to K4) in the following order: Aco-1, Pgi-1, and Dia-3 (K1), Tpi-2, Got-2, and Lap-1 (K2), Got-3 and Tpi-1 (K3) and Pgm-1, Pgm-3, 6-Pgd-2 and Skd-1 (K4). Dia-2 and Got-1 remained unlinked. The possible duplication of a PGM locus and a 6-PGD locus is discussed.     

Genetic analysis and nomenclature for seven isozyme systems in Brassica nigra, B. oleracea and B. campestris

General criteria for the assignment of names to enzyme systems, regions of activity, isozyme loci and allozymes have been lacking in crucifer species. This paper proposes a standard nomenclature for seven isozyme systems in the three diploid species of U's triangle: Brassica nigra, B. oleracea and B. campestris. Gel/electrode buffers, which provided the best resolution for seven isozyme systems, acid phosphatase (APS), aconitase (ACO), leucine aminopeptidase (LAP), 6-phosphogluconate dehydrogenase (6 PGD), phosphoglucoisomerase (PGI), phosphoglucomutase (PGM), and triosephosphate isomerase (TPI), were proposed as standards. Isozyme genetic analysis was determined for B. oleracea and B. campestris from previous studies and by segregation of selfed progenies of heterozygous B. nigra plants. Several populations were studied and 148 allozymes at the 18 loci observed were described for the three species. Their relative mobility was studied using a pure line of oilseed rape as reference. The comparison of the different alleles within and between the species is discussed.     

Diversity in the wild potato species Solanum chacoense Bitt.

Summary The morphological and isozyme variation was studied in 22 accessions of Solanum chacoense from Paraguay and Argentina. Clear geographic groups were identified through the use of multivariate analyses. S. chacoense from mountain sites in Argentina could be readily distinguished from plains forms from Paraguay, on the basis of several correlated morphological characters. Three isozyme systems, namely phosphoglucose isomerase (PGI), glutamate-oxaloacetate transaminase (GOT) and peroxidase (PRX) were studied using starch gel electrophoresis. The banding patterns indicated that for each isozyme there were several loci, which were polymorphic. A genetic interpretation of one of the PGI loci was made, and indices of genetic diversity and genetic identity calculated. Principal components analysis, cluster analysis and genetic diversity indicated a close relationship between the geographical groups. These results are discussed in the context of in situ genetic conservation.     

Genetic Control of Five Isozyme Systems in Sugar Beet (Beta vulgaris L.)

Genetic markers are most useful in plant breeding but so far only a few morphological and isozyme markers are known in Beta vulgaris. In this paper, the isozyme systems aconitase (AGO), NADH-:dihydrolipoamiddehydrogenase (DIA), esterase (EST), fructose-1,6-bisphosphatase (FDP), and hexokinase (HK) were genetically analysed. Isoelectric focussing (IEF), vertical polyacrylamide gel electrophoresis (PAGE) and starch gel electrophoresis (SGE) were used to separate the isozymes. A total of eight loci could be identified. The allelic forms of Aco-1, Dia-1, Est-1, Est-5 and Hk-1 are active monomers. The gene products of Est-3 and Fdp-2 are active as dimers. Est-2 also showed allelic forms without activity; null-alleles.     

苹果酸脱氢酶在番茄F1杂种纯度检测中的应用

本文应用垂直板不连续系统的聚丙烯酰胺凝胶电泳（ＰＡＧＥ）法,分析了５个杂交一代种（佳粉一号、佳粉二号、佳粉十号、佳粉十五号、双抗二号）发芽肿种苗的五种同工酶（苹果酸脱氢酶（ＭＤＨ）、乙醇脱氢酶（ＡＤＨ）、磷酸葡萄糖变位酶（ＰＧＭ）、酯酶（ＥＳＴ）、异柠檬酸脱氢酶（ＩＤＨ）。发现５个杂交一代种中,３个要交一代种与其双亲的苹果酸脱氢酶（ＭＤＨ）谱带有有明显稳定的区别。两个杂交一代种与其双亲酯（ＥＳＴ）     

Genetic variation for isozyme genes and proteins in spanish primitive cultivars and wild subspecies of Lens

Summary An analysis of the variability for genes encoding seven isozyme systems and storage proteins in a collection of cultivated and wild accessions of Lens is reported. The collection, which is part of the Spanish INIA Cenebank, contains the ssp. culinaris, orientalis, odemensis, nigricans and ervoides, and presents a high degree of genetic diversity both within and between the accessions. A total 25 loci were examined; of these, 18 were polymorphic (the 7 genes encoding storage proteins, and the following isozyme loci: Acp-1, Acp-2, Cpx-1, Cpx-2, Aat-p, Aat-m, Lap-1, Mdh-2, Mdh-3, Mdh-4 and 6pgd-p) and 7 were monomorphic (Aat-mb, Aat-c, Mdh-1, Mdh-5, 6pgd-2, Pgm-c and Pgm-p). The phylogenetic relationships between subspecies were analyzed using the allelic frequencies. The study suggests that orientalis and odemensis share more biochemical characters than the other subspecies, and that those subspecies keep an intermediate position between Lens culinaris and Lens nigricans.     

Genetic control of alcohol dehydrogenase, malate dehydrogenase, and phosphoglucomutase isozymes in lima bean (Phaseolus lunatus L.)

A suitable electrophoretic separation method for alcohol dehydrogenase (ADH). malate dehydrogenase (MDH). and phosphoglucomutase (PGM) from P. lunatus has been developed. Two loci (Adh-2 and Pgm-2) showed codominant inheritance and fitted Mendelian ratio. ADH isozyme banding patterns indicate a dimeric quaternary structure. while those of PGM were in agreement with a monomeric nature. The cytoplasmic location of two MDH isozymes (Mdh-1 and Mdh-2) selectively inactivated by homogenization in an ascorbic acid solution was demonstrated. However. distorted ratios were observed for Mdh-2 segregation. On the basis of MDH isozyme banding patterns observed in five progeny families, il is suggested that this enzyme system is a dimeric protein encoded by at least three codominant genes (Mdh-1 .Mdh-2 and Mdh-3). Joint segregation tests between pairs of segregating loci (Adh-2, Mdh-2, and Pgm-2) indicated that each of them is inherited independently.     

Potential and limitations of isozymes for chromosomal localization of resistance genes against barley mild mosaic virus (BaMMV)

Summary To assess the possibilities offered by isozymes to locate resistance genes against barley mild mosaic virus (BaMMV), the isozyme patterns of 19 barley (Hordeum vulgare L.) genotypes carrying genes different from ym4 were determined. Of the 15 isozyme systems tested, only three were polymorphic, namely aconitate hydratase, esterase, phosphogluconate dehydrogenase, providing markers on four of the seven barley chromosomes. Studies of F₂ progenies derived from three crosses between resistant genotypes and susceptible varieties failed to reveal linkage between resistance genes and isozymes. Another goal of the experiment was to study the linkage relationships between ym4 and the esterase locus (Est1-Est2-Est4). Our estimates of the recombination rate between these two loci (3.41 and 8.32%) were in the range of those reported between these esterases and one of the resistance genes of the Chinese variety Mokusekko 3.     

Isozyme characterisation of Indian maize inbreds

The need for precise characterisation of crop materials has assumed importance in any established sui generis system for effective protection of plant varieties. Considering this requirement, 37 Indian maize inbreds were analysed for allozyme variations. Seven enzyme systems comprising 16 isozyme loci were analysed using starch gel electrophoresis. The allelic variants were designated using the well-characterised maize inbred Mo 17 as a standard. A total of 29 alleles were scored at the 16-isozyme loci studied. Malate dehydrogenase (Mdh), acid phosphatase (Acp), phosphoglucoisomerase (Pgi), 6-phosphogluconate dehydrogenase (Pad) and isocitrate dehydrogenase (Idh) were the most informative isozyme systems for characterisation of the maize inbreds. These enzyme systems were also useful in detecting and quantifying the extent of `off-types' in each seed lot analysed. The percent off-types (inclusive of the admixtures and segregates) were as high as 47 to 50 percent in seed lots of a few of the inbreds. The results of the study were also useful in studying genetic diversity among the inbreds. An UPGMA based cluster analysis of the allozyme data revealed presence of only moderate genetic diversity among the Indian maize inbreds. This is of significance in crop yield stability as these inbreds have been used extensively in the production of F₁ hybrids occupying large area under maize cultivation in India. This revised version was published online in July 2006 with corrections to the Cover Date.     

Heredity of seventeen isozyme loci in cassava (Manihot esculenta Crantz)

Summary Starch gel electrophoresis was used to assess isozyme polymorphism in two Manihot species. Crude extracts were obtained from leaves and pollen. Ten enzymes were examined for their polymorphism in a germplasm collection of 365 cultivated plus 109 wild accessions, mainly from Africa. The inheritance of these enzymes was examined using 13 intra and interspecific progenies. Seventeen polymorphic loci were found for the ten enzyme systems, with 59 alleles. All the markers showed disomic heredity and three linkage groups were identified.     

Genetic variability among Turkish pop, flint and dent corn (Zea mays L. spp. Mays) races: Enzyme polymorphism

To determine magnitude and pattern of genetic variation, 32 Turkish corn accessions available from the USDA/ARS North Central T-Regional Plant Introduction Station (NCRPIS) collections (Ames, Iowa), representing pop, flint and dent corn races, different climatic, geographic and topographic areas in Turkey, were identified and, 19 isozyme systems were studied. Thirty-nine alleles were detected by 19 isozyme loci in 32 accessions. The PGD-2, Mmm-1, GOT-3 and IDH-1 loci were found to be monomorphic in all accessions. Mean number of alleles per locus varied between 1.2 in Balıkesir-167949 accession to 1.7 in Ankara-177600, Trabzon-185062, Eskişehir-204822 and Samsun-239573 accessions. The proportion of polymorphic loci ranged from as low as 15.8% in Balıkesir-167949 to as high as 57.9% in Trabzon-185049 accession. Observed heterozygosity was the highest in Adana-183779 and the lowest in Ankara-204800 accession. Genetic identities ranged from 0.823 for 170881-Kocaeli and 167949-Balikesir pair to 0.997 for 182327-Iğdır and 168008-Kırklareli pair. Dendrogram constructed by using Nei's genetic distances (1978) revealed three clustering groups, though one of the clusters included only 170881-Kocaeli accession. It is concluded that170881-Kocaeli accession must have experienced with intensive selection, inbreeding and/or bottleneck effects in the past. Corn germplasm managers and breeders could use the results of the present studies for monitoring genetic resources, accession identification, and sampling genetic diversity, but agronomic characteristics of these corn accessions are also needed for a better utlization of Turkish corn land races evolved over the years. This revised version was published online in August 2006 with corrections to the Cover Date.     

Isozyme polymorphism in Festuca rubraL.

Summary Six Festuca rubra populations from Europe and Scandinavia were studied for variation at three isozyme loci; phosphoglucoisomerase (PGI-2), glutamate oxaloacetate transaminase (GOT-3) and superoxide dismutase (SOD-1). Seven alleles were found at the Pgi-2 locus, four at the Got-3 locus and five at the Sod-1 locus. Most plants were heterozygous and up to five alleles were found in the same plant at the Pgi-2 locus. Each population could be distinguished by the presence or absence of certain alleles or by differences in the frequencies of the alleles present. Values for the Shannon diversity index were calculated which showed that there was considerable heterogeneity both within and between loci. In general, 53% of this diversity could be attributed to within population variation.     

Inheritance of reduced plant height in the sunflower line Dw 89

The objective of the present research was to study the inheritance of reduced plant height in the sunflower line Dw 89. Plants of the cytoplasmic male sterile version of this line, cmsDw 89 (mean plant height of 47.4 cm) were crossed with plants of the restorer line RHA 271 (mean of 120.9 cm). F₁ plants averaged 120.4 cm, which indicated dominance of standard over reduced plant height. F₂ plants followed a segregation pattern of 1 : 15 (reduced : normal height), suggesting that reduced plant height in Dw 89 is controlled by alleles at two loci, designated Dw1 and Dw2. Class assignment in the F₂ was confirmed through the evaluation of the F₃ generation. Backcrosses to Dw 89 segregated with 1 : 3 (reduced : normal height) ratios, which confirmed the digenic inheritance of the trait. The evaluation of plant height distributions in F₃ families suggested possible genetic interaction between the Dw1 and Dw2 loci.     

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

Summary 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 BC₂F_4:6 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.Selection for G. max alleles at the isozyme loci was not effective in recovering the recurrent parent phenotype in either cross. In cross 1, however, BC₂F₄-derived lines in the 0- or 1- locus class more closely resembled the G. max parent than lines in the 4- or 5- locus classes for most of the agronomic and seed composition traits evaluated. Significant associations were found between particular isozyme genotypes and every trait analyzed. The estimated effect of genes linked to the Pgm1 locus was a delay in maturity of 6.0±3.4 days. In cross 1, the Idh2 locus was associated with a significant effect on linolenic acid content. The percentage of variation accounted for by the models of estimation varied according to the heritability of the trait. The R² was high (up to 78%) for maturity, lodging, and vining, and low (up to 21%) for seed yield. Most of the variation was associated with the BC₂F₁ family from which the lines were derived. There was little evidence that digenic epistasis was an important source of variation.Journal Paper No. J-13505 of the Iowa Agric. Home Econ. Exp. Stn., Ames, IA, Project 2475.     

Application of isozyme electrophoresis for purity testing and cultivar identification of F1 hybrids of Brassica oleracea

Summary Six isozyme genes were analyzed in seed samples of 65 commercial F₁ hybrids of four horticultural groups of Brassica oleracea (cabbage, Brussels sprouts, sprouting broccoli and cauliflower). Results obtained from electrophoretic assays led to the following conclusions: 1) the electrophoretic test of F₁ hybrid purity was possible in 59 (91%) of the hybrids analyzed, since their inbred parents were apparently fixed each for a different allele in at least on of the loci studied; 2) forty-eight (74%) of the hybrids were individually distinguished by their isozyme phenotype; 3) high levels of segregation in the inbred parents were inferred from the analysis of a sample of seeds of each hybrid.