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1.
A. Hamdi  W. Erskine 《Euphytica》1996,91(2):173-179
Summary Susceptibility to drought stress is a key factor in dry land lentil (Lens culinaris Medikus) production in the Mediterranean region of West Asia and North Africa. This study examined the response to drought stress of 121 accessions representing all subspecies of the genus Lens; cultivated, and the wild L. culinaris ssp. orientalis (Boiss.) Ponert, L. culinaris ssp. odemensis (Ladiz.), L. nigricans M.B. Godr. ssp. nigricans Godr. and L. nigricans ssp. ervoides (Brign.) Ladiz. for their potential use in breeding for dry land conditions. Accessions were grown under two moisture regimes (dry land and dry land plus supplemental irrigation) at Breda, Syria during the 1990–91 and 1991–92 seasons. The cultivated lentil had markedly superior seed and straw production than did the wild Lens species. Time to flowering accounted for less than 10% of the variation in yield of wild accessions under rainfed conditions in the two seasons, showing that, in contrast to the cultivated germplasm, drought escape was relatively unimportant in wild lentil. Performance under drought in wild lentil, measured in terms of dry land seed yield or drought susceptibility index (S), was randomly distributed among collection locations with little relation to collection site aridity. Direct selection of wild lentil germplasm for biomass yield under dry conditions is of little value and an evaluation of wild accessions in hybrid combination is needed.  相似文献   

2.
Summary A survey of allozyme polymorphism at 11 loci was carried out on 439 accessions from the genus Lens. This comprised 153 Lens culinaris subsp. orientalis, 35 L. odemensis, 117 L. ervoides, 32 L. nigricans, 2 of a differentiated cytotype of L. nigricans and 100 landrace accessions of the cultivated lentil (L. culinaris subsp. culinaris), from 10 different countries. The aim of the survey was to determine intra-specific genetic diversity and species relationships, based on phylogenetic and phenetic analyses, particularly regarding the position of L. odemensis and the differentiated cytotype of L. nigricans. Diversity was described by three statistics. The level of diversity in the cultivated taxon was lower than in any of the wild species according to two of these statistics, the percentage of polymorphic loci and mean number of alleles per locus. For the third measure (Nei's mean genetic diversity) it was only greater than L. ervoides. Genetic diversity statistics of the wild species indicated differences in the nature of between-population genetic diversity within the different taxa. Phylogenetic analysis suggests that L. odemensis and L. ervoides evolved from a common ancestor, and L. culinaris subsp. orientalis subsequently evolved from L. odemensis. Phenetic analysis, however, places L. odemensis closer to L. culinaris subsp. orientalis than to L. ervoides. Nei's mean genetic distance of L. odemensis from both L. culinaris subsp. culinaris (0.204) and L. culinaris subsp. orientalis (0.110) was greater than the distance between them (0.062). This evidence is not conclusive in determining whether L. odemensis should retain its specific status. Further crossability studies should be carried out on a range of genotypes to assess the potential for gene flow. The evidence presented shows the differentiated cytotype of L. nigricans to be quite distinct from other L. nigricans accessions, both phenetically and phylogenetically. This indicates that the differentiated cytotype of L. nigricans may constitute a new taxon. Discriminant function analysis reveals that isozymes may be useful in validating species classification.  相似文献   

3.
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.  相似文献   

4.
Summary Chloroplast DNA restriction fragment lenght polymorphisms (RFLP) were used to examine the taxonomic relationships of cultivated and wild lentil (Lens Miller) species and identify the extent of genetic variation in this genus. Twelve accessions representing all Lens subspecies were digested with four hexanucleotide-recognizing restriction endonucleases. These digests randomly surveyed 540 base pairs, or 0.4% of the approximately 125 kilobase lentil chloroplast genome. A high degree of gragment length conservation was seen among members of crossability group I, i.e., L. c. ssp. culinaris, L. c. ssp. orientalis and L. c. ssp. odemensis. Accessions of the two subspecies comprising crossability group II, i.e., L. n. ssp. nigricans and L. n. ssp. ervoides, showed the greatest amount of variation when compared to the cultivated lentil, L. c. ssp. culinaris. Limited variation was observed within subspecies except for L. n. ssp. nigricans, where accessions of the normal cytotype were highly polymorphic to those of the differentiated cytotype. Chloroplast DNA RFLPs reaffirm hypotheses that propose L. c. ssp. orientalis as the progenitor to the cultivated lentil. The implications of this study on taxonomy and genetic resources is also discussed.  相似文献   

5.
F. Lefèvre  A. Charrier 《Euphytica》1992,66(3):171-178
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.  相似文献   

6.
Summary Four newly detected accessions of wild barley (Hordeum vulgare ssp. spontaneum) resistant to powdery mildew caused by Blumeria graminis f. sp. hordei were studied with the aim of finding the number of genes/loci conferring the resistance of individual accessions, the type of inheritance of the genes and their relationships to the Mla locus. F2 populations after crosses between the winter variety ‘Tiffany’ and four wild barley accessions and use of microsatellite DNA markers were focused on the identification of individual resistance genes/loci by means of their chromosomal locations. In PI466495, one locus conferring powdery mildew resistance was identified in highly significant linkage with the marker Bmac0213. This location is consistent with the known locus Mla on chromosome 1HS. In the other three accessions the resistance was determined by two independent loci. In PI466197, PI466297 and PI466461, one locus was identified on chromosome 1HS and three new loci were revealed on chromosomes 2HS (highly significant linkage with Bmac0134), 7HS (highly significant linkage with Bmag0021) and 7HL (significant linkage with EBmac0755). Our prospective aim is identification of further linked DNA markers and the exact location of the resistance genes on the barley chromosomes.  相似文献   

7.
Summary We report on the inheritance of 11 morphological markers and 17 isozymes in lentil (Lens culinaris). The monogenic inheritance of 11 morphological markers and 11 isozymes is confirmed. The inheritance of six isozymes (Aco-2, Enp, Est-3, Est-4, Lap-3, and Mdh-m) is reported for the first time in lentil. This brings the total number of described genes in lentil to 78. Cases of disturbed segregation were more frequent than expected by chance. It is suggested that disturbed segregation was in most cases caused by linkage with a piece of chromosome that showed preferential elimination in crosses between Lens culinaris ssp. odemensis and other subspecies. The prevalence of disturbed segregation in crosses with Lens culinaris ssp. odemensis could limit the usefulness of this subspecies in genetic and linkage studies.  相似文献   

8.
Seed weevil (Bruchus spp.) is one of the most damaging pests to lentil crop, and the current chemical treatments to control this insect present numerous disadvantages. In this work, we have searched for resistant or almost resistant lentil cultivars to be used as potential sources of genes for resistance to bruchids as a more sustainable and environmentally friendly approach to diminish harvest loss. Thus, a lentil germplasm collection of 571 accessions from 27 different countries, and including wild species was screened for susceptibility to seed bruchids under natural field conditions in Central Spain. Infestation was evaluated in comparison with a check (lentil cultivar ??Lyda??) according to the number of eggs per pod and the infestation rate in seeds (IR). A large variation of IR (0?C70?%) was observed among accessions although, in general, wild species were consistently less affected by bruchids than the check. A total of 32 accessions, including Lens culinaris Medikus subsp. culinaris, Lens culinaris Medikus subsp. orientalis (Boiss.) Ponert, Lens nigricans (M. Bieb.) Godr., and Lens lamottei Cezfr., showed lower infestation rates than the check and were selected as potential sources of resistance to this pest. Potential mechanisms of resistance of selected accessions and their inclusion in a breeding program are outlined.  相似文献   

9.
Summary Accessions of Hordeum vulgare ssp. spontaneum, the wild progenitor of barley, collected in Israel (70), Iran (15) and Turkey (6) were screened for seedling response to four isolates of Rhynchosporium secalis, the pathogen causing leaf scald in barley. Resistance was very common in the collection (77%) particularly among accessions from the more mesic sites (90%). The genetics of this resistance were investigated in fifteen backcross (BC3) lines that contained an isozyme variant from H.v. ssp. spontaneum in a H.v. ssp. vulgare (cv. Clipper) background and were resistant to scald. Segregation in the BC3F2 families conformed with a single dominant resistance gene in 9 of the 15 lines. Scald resistance and the isozyme marker were closely linked in three of the BC3-lines, loosely linked in four and unlinked in the remaining eight. Scald resistance genes were identified on barley chromosomes 1, 3, 4 and 6. Crosses between several of the scald resistant BC-lines together with the linkage data indicated that at least five genetically independent resistances are available for combining together for deployment in barley. The linkage of scald resistance in several BC3-lines to the isozyme locus Acp2 is of special interest as this locus is highly polymorphic in wild barley.  相似文献   

10.
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 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.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.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
Summary Annual beets in the genus Beta section Beta represent an important genetic resource. Representative accessions of annual beets from a beet germplasm collection were analysed using RAPD to assess the patterns of variation and relationships among them. Using arbitrary primers, markers showing variation across accessions were identified. A dendrogram of similarity was produced using these molecular markers. All the accessions analysed were classified into three major groups corresponding to species or subspecies macrocarpa, adanensis and maritima. Macrocarpa was shown to be the most divergent group in this section. Using RAPD molecular markers, it was possible to ascribe an accession to one of three taxonomic groups and overcome much of the confusion encountered when morphological traits are used for identification. The group of maritima was found to be more polymorphic than either the group of macrocarpa or adanensis at both accession and subspecies levels.  相似文献   

14.
A collection of 142 accessions of 23 Malus species, derived hybrids and cultivar accessions from the USDA-ARS Plant Genetic Resources Unit's core collection, which represents an extensive range of Malus species, was screened with a set of previously described SSR (simple sequence repeat) markers. The markers were used to determine genetic identities, estimate genetic diversity, identify genetic relationships among the accessions, and determine the utility of SSR primers developed from Malus ×domestica for making genetic assessments across the whole Malus genus. All eight primer pairs amplified multiple fragments when used in polymerase chain reactions with DNA from these accessions. High levels of variation were detected with a mean of 26.4 alleles per locus and a mean direct count heterozygosity across all eight loci equal to 0.623. The eight primer pairs used in this study unambiguously differentiated all but five pairs of accessions in this collection of 142 accessions of 23 Malus species, derived hybrids and cultivars. These SSR data were not useful in identifying genetic relationships among this diverse collection of accessions, with the majority of the accessions not clustering in ways concordant with taxonomic information and/or geographic origin. The resulting phenogram resolved only two meaningful clusters, for the taxonomically isolated Section Chloromeles and for M. fusca accessions, reflecting genetic relationships arising from geographic origin. The detection of identical accessions in the collection, which were previously considered to be unique, highlights the critical need to further bolster collections of certain Malus species. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
A collection of 14 triticale (X Triticosecale Wittmack) varieties commonly grown in Portugal were analysed using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to describe allelic diversity in the storage proteins encoded at the Glu-1 (Glu-A1, Glu-B1 and Glu-R1), Gli-1 (Gli-A1 and Gli-B1), Glu-3 (Glu-A3 and Glu-B3), Glu-B2 and Gli-R2 loci. Several alleles were identified: 10 at the loci encoding for high molecular weight(HMW)subunits (seven for glutenin and three for secalins), eight for low molecular weight glutenin subunits, four for γ-gliadins and three for 75K γ-secalins. These results showed that triticale varieties grown in Portugal exhibit great genetic diversity. Knowledge of the diversity of these storage proteins, which are the major gluten components, will greatly increase our understanding of the quality differences that might exist between triticale varieties.  相似文献   

16.
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.  相似文献   

17.
A. A. Levy  M. Feldman 《Euphytica》1989,41(1-2):113-122
Summary The genetic control of grain protein percentage (GPP) in the wild tetraploid wheat, Triticum turgidum var. dicoccoides, was determined by crossing four accessions of this taxonomic variety with durum cultivar Inbar, and analyzing the parents, F1 and F2 populations. Reciprocal crosses indicated no cytoplasmic effect on GPP. The F2 variation was continuous in all crosses, showing no transgressive segregation. However, crosses between different accessions of var. dicoccoides showed transgressive segregation indicating the presence of different genes for high GPP in these accessions. Grain protein percentage was mostly codominant with high GPP, showing either no dominance, or a weak dominance. Heritability coefficients (broad sense) ranged from 0.30 to 0.53. Correlation coefficients between GPP and yield components were usually significantly negative, with the exception of the number of spikelets per spike, and in some crosses, grain weight.The number and chromosomal location of genes coding for high GPP were determined by the association between GPP and 27 markers (23 morphological and 4 biochemical markers). For this purpose, the genetic control of these markers, their linkage groups and chromosomal location were studied. At least four loci for high GPP that segregated in the F2 populations are suggested: one on chromosome arm 1AS, marked by the black glume gene (Bg); one on 1BS, marked by the HMW gliadin locus Gli-B1; one on group 5, marked by the genes for beaked glume (Bkg) and toothed palea (Tp); and one on group 7, marked by the kinky neck gene (Kn). The relationship between GPP and several yield components was studied in a similar manner. In general, loci of markers that correlated positively with high GPP were not correlated with a decrease in yield components. Moreover, several loci of var. dicoccoides were associated with an increase in yield components.The utilization of markers for chromosomal location of genes coding for quantitative traits is compared to the technique of aneuploid analysis, commonly used in wheat. The significance of the above findings for breeding is discussed.  相似文献   

18.
An assessment of cultivated emmer germplasm for gluten proteins   总被引：5，自引：0，他引：5  
The storage protein composition of 61 accessions of Triticum dicoccum was analyzed by SDS-PAGE (HMW- and LMW-glutenin subunits) and Acid-PAGE (gliadins). In the HMW-glutenin subunits, four allelic variants at the Glu-A1 and eight at the Glu-B1 locus were detected resulting in a total of 17 patterns. The Glu-B1 locus was found to be more polymorphic than the Glu-A1 locus. Interestingly, the presence of HMW subunits like 13+16, 2∗ and 1 associated with good quality was observed. Three accessions were null for both the Glu-A1 and Glu-B1 loci. There was less variation for gliadins. Three different gamma gliadin fractions coded by Gli-B1 locus were detected and there were eight different LMW-B glutenin patterns at the Glu-3 loci. The variability can be used to improve the utility of this crop.  相似文献   

19.
Mist-chamber, field, and detached leaf inoculation procedures identified plants resistant to bacterial soft rot [Erwinia carotovora subsp. carotovora, (Ecc)] in Brassica rapa and related species. The mist-chamber seedling inoculation provided the best correlation of mean disease severity ratings with the field plant inoculation (r = 0.67**) and was used to identify resistant materials. The optimum mist-chamber incubation conditions to distinguish the resistance of accessions were 23 °C and 100% RH and were used for primary screening. A total of 752 accessions of B. rapa and related Cruciferae were screened. In general, accessions of B. oleracea were more resistant than accessions of B. rapa. Within B. rapa, subspecies pekinensis and chinensis were more susceptible than other subspecies. No completely resistant material was found. In species of B. rapa, only 7% of accessions showed some degree of resistance with plant-to-plant variation within the accessions. G30444, G30449, and AVRDC2837 were identified as the most resistant materials in B. rapa by both mist-chamber and field inoculations. The resistance was correlated between an USA isolate (Geneva-1) and two Chinese isolates (RL4-1 and RL-19) of Ecc. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

20.
L. Westphal  G. Wricke 《Euphytica》1991,56(3):259-267
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.  相似文献   

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