bluuebunny/crossref_metadata_2025 huggingface dataset:
Elymus canadensis×Secale cereale Amphiploids. II. Chromosome Constitutions and Pairing of Open‐Pollinated Progeny
Authors: Park C. H. , Walton P. D.
Published: April 2006

Eleven C2 and two C3 0pen‐pollinated plains from Elymus canadensis × Secale cereale amphiploid plants (2n = 6x = 42, SSHHRR) were examined for chromosome constitution and meiosis. Chromosome numbers of the progeny varied: 2n = 26, 27, 28, 36, 37, 39, 40, and 41. Elimination of portions of genome constituents were made at random and were irregular in all o the progeny. Monosomic (2n = 41) and nullisomic (2n = 40) plants lost one to two E. canadensis or S. cereale chromosomes and showed average of 17 to 18 bivalents and 4 to 5 univalents per cell at Ml. The C2, aneuploid plants with 36 to 41 chromosomes seemed to result from selfing or intercrossing among; the C1 amphiploid plants, while the plants of 2n = 26 to 2S (6–9 II + 10–141) might originate from outcrosses of the Cl amphiploid to S. cereale. Bivalent pairing might be preferentially intragenomic (S‐S, H‐H, or R‐R). The occurrence of multivalents indicates a low potential of both intragenomic and intragenomic pairing; Pollen of the lour plants showed poor stainability (1 to 13 %) and no seed set in any of the progeny.
The Inheritance of Resistance to Septoria Glume Blotch II. The Wild Wheat Species Aegilops speltoides
Authors: Ecker R. , Cahaner A. , Dinoor A.
Published: April 2006

The inheritance of resistance in the wild wheat species Ae. speltoides L. to Septoria glume blotch (Septoria nodorum Berk.) was investigated. It was characterized by two parameters measured on detached leaves, namely lesion size (LS) and length of latent period (LP), and by the severity of the disease under field conditions (DS). The genetic analysis was based on the F1 and F2 generations of a 4 × 4 diallel cross between four Ae. speltoides accessions showing differential resistance to the pathogen. The three parameters of resistance were highly correlated. Considerable heterosis for resistance was found for each of the parameters in most of the diallel combinations. The estimates of broad‐sense heritability were moderately high (0.50 — LS, 0.60 — LP, 0.52 — DS), while the estimates of narrow‐sense heritability were low (0.16 for LS, 0.20 for LP, 0.25 for DS). There were no indications for genie interaction. It is suggested that the resistance is controlled by at least two genes with over‐dominance of the alleles for higher resistance. Highly resistant Ae. speltoides accessions are a potential source of germplasm for improving the resistance of cultivated wheats to Septoria glume blotch. The possibility of using dominant alleles for resistance in hybrid cultivars is discussed.
Production of Eruca‐Brassica Hybrids by Embryo Rescue
Authors: Agnihotri Abha , Gupta Vibha , Lakshmikumaran Malathi S. , Shivanna K. R. , Prakash Shyam , Jagannathan V.
Published: April 2006

Allied species of crop Brassicas have potential value as donors of useful nuclear/organelle genomes. Eruca sativa, a member of subtribe Brassicineae, is resistant to white rust and well adapted to drought. Attempts to hybridize it with Brassica campestris by conventional methods were unsuccessful. However, hybrids were obtained by embryo rescue and the hybrid embryos were found to produce numerous secondary embryos in upto 7 to 8 subcultures. Plantlets developed from them exhibited morphological characteristics of both parents. The chromosome number of 2n = 42 showed that they were amphidiploids. The plants were allotctraploids (2n = 42) and showed 21 bivalents at M1 of meiosis. Hybridization of total DNA of the hybrids with two probes, a B. campestris tandem repeat DNA and 18s ribosomal DNA of wheat showed that it was derived from the genome of both parents. The hybrids are self‐fertile and show the same high fertility even in A3 generation. They were selfed or crossed with B. juncea, B. campestris and B. nigra to screen for useful agronomical traits. Six more embryos of E. saliva × B. campestris have been obtained and their growth is being studied. Preliminary small scale field trials indicate that the selfed hybrid is comparable in yield with a high yielding commercial variety of B. juncea.
Transformation of Diploid and Tetraploid Potato Clones with the rol C Gene of Agrobacterium rhizogenes and Characterization of Transgenic Plants
Authors: Fladung M.
Published: April 2006

Diploid and tetraploid potato clones were transformed with the rol C gene from Agrobacterium rhizogenes under the control of the cauliflower‐35‐S promoter. Parameters proper to the sink and source attributes and hormone treatments have been considered to study the effect of the gene on yield physiology of the potato plant. The expression of the rol C gene in diploid and tetraploid potato lines induced drastic developmental abnormalities like dwarfism and increased tillering. Hormonal treatments revealed a different behavior of rol C transformams and controls. This supports the conclusion that the gene product of the ml C gene interacts with the hormonal status of the plant. Grafting experiments showed the non‐ditfusable nature of rol C gene product. Tuberization was studied in‐vitro and in‐planta. Relevant differences in tuber shape and eye number were noted between rol C transfonnams and controls. Tuber yields in‐planta in greenhouse or in growth chamber resulted higher in the controls; a significant increased number of tubers per plant was found, however, in both diploid and tetraploid rol C transformants. The effect of the rol C gene was apparently too drastic for diploid and tetraploid potatoes; weaker and tissue specific promoters may be necessary to induce only those modifications which are wanted for this crop. The experiments nevertheless proved that one single gene was capable in potato to affect substantially the manifestation of vieldmg attributes.
Linkage of Rust Resistance Genes from Wild Barley (Hordeum spontaneum) with Isozyme Markers
Authors: Feuerstein U. , Brown A. H. D. , Burdon J. J.
Published: April 2006

Eighty‐three third backcross lines which comprise a set of near isogenic lines (NIL's) of the barley cultivar ‘Clipper’ but each carrying a different chromosomal segment from Hordeum spontaneum, marked with a distinct isozyme, were tested for resistance to three races of the barley leaf rust pathogen (Puccmia hordei). Fourteen lines showed resistance to at least one race and three showed resistance to all three races. The resistance in two of these lines was controlled by separate, single partially dominant genes. In one case the resistance gene named Rph1O was on chromosome 3 and linked (r = 0.15 ±0.05) with the isozyme locus Est2. In the second case, the gene (Rph11) was on barley chromosome 6 and linked (r = 0.07±0.02) with the isozyme locus Acp3 and (r = 0.11±0.02) with Dip2.
Genetic Improvements in the Structure of Oat Stands in Northern Growing Conditions during this Century
Authors: Peltonen‐Sainio Piujo
Published: April 2006

The changes of morphological properties of 13 Finnish oat varieties released between 1921 and 1988 and 13 Hankkija's breeding lines were evaluated in field trials. Twenty‐two characteristics of oat stands were measured. The relationship between years of cultivar release and characteristics of oats was studied by using the linear regression analyses and Spearman's rank correlation analyses.

In both years of experiment there was a significant positive linear relationship between year of cultivar release and size and weight of the flag leaf, and mean panicle filling rate. The correlation was significant, but negative between year of release of cultivar and plant height. Also other relationships arc discussed.
Effect of Mutagenic Treatments on Somaclonal Variation in Wheat (Triticum aestivum L.)
Authors: Cheng X. Y. , Gao M. W. , Liang Z. Q. , Liu K. Z.
Published: April 2006

Different wheat genotypes were treated with gamma‐rays, sodium azide (SA) and EMS before tissue culture and immature embryos from M1 plants or plants shortly after exposure to gamma‐rays were used to initiate callus culture. Thousands of plants were regenerated and used to investigate the effect of mutagenic treatments on the regenerated plants and somaclonal variation in the M3R2 and M2R2 generations. The results showed that mutagen‐induced damage in terms of reduction in plant height, fertility and spike length were not outstanding in the regenerated plants as compared with the untreated control. In the M3R2 generation, only SA treatment had significantly higher frequencies of somaclonal variations than the control. Increases in the variation frequencies were observed when explant embryos were irradiated with 2.5 and 5 gy gamma‐rays and the highest frequency appeared when embryos were exposed to 5 gy gamma‐rays on the 5th day after anthesis. Increased variation spectra also resulted from mutagenic treatments and most of the variants recovered were unsuitable for plant improvement.
An Improved Assessment Procedure for Breeding for Resistance to Septoria nodorum in Wheat
Authors: Walther H.
Published: April 2006

A yield‐based assessment procedure for breeding for resistance to Septoria nodorum (SN) is presented. Artificially infected as well as fungicide‐protected plots were analyzed for each genotype. Considerable increase in precision of disease scores was gained by using an assessment matrix for different plant organs and time intervals during disease development. This technique resulted in yield loss: disease attack correlations up to r = 0.85:** and raised coefficients of heritability (h2b= broad sense heritability) with h2b= 0.72 for % yield loss and h2b= 0.86 for SN‐attack, calculated for a 3‐year replicated field experiment with 105 winter wheat cultivars.
Generation Mean Analysis of Inheritance of Resistance to Pyrenophora teres in Barley
Authors: Cherif M. , Harrabi M.
Published: April 2006

F1, F2, Fl × parentl (BC1), and Fl × parent2 (BC2) generations resulting from four crosses among seven cultivars of barley used in national and international breeding programmes were tested at the seedling stage for their resistance to a mixture of five isolates of Pyrenophora teres. Four methods were used to assess disease resistance: infection type (IT), average lesion size (ALS), number of lesions per unit leaf area (NL) and percent leaf area infected (PLAI). Gene actions were estimated by generation mean analysis on each of the four crosses and on each of the evaluation methods. Significant additive and additive × additive epistatic effects were found. Infection type and percent leaf area infected were found to be highly correlated in all four crosses. These results suggest that barley breeders could improve the level of resistance to P. teres by making appropriate crosses between highly susceptible barley cultivars.
Isoenzymes and their Importance for Breeding Autopolyploids
Authors: Skiebe K. , Seliger Petra
Published: April 2006

Isoenzyme analyses have been carried out in polyploid rye. Taking into consideration zymograms at the diploid level, conclusions can be drawn concerning the genetics of band positions and band intensity. This is rather clear with the aspartate aminotransferase and the NAD‐specific aromatic alcohol dehydrogenase. For both isoenzymes one gene locus with two alleles is responsible in the zones analyzed. In both cases a superdominance is assumed. Thereby nulliplex‐, simplex‐, duplex‐, triplex‐ and quadru‐plex types can be distinguished. For the banding pattern with the leucine aminopeptidase two gene loci with two alleles each are responsible. With allelic interaction codominance is supposed. On this base it is possible to differentiate between homozygosity and heterozygosity. Difficulties in autopolyploid breeding can be overcome by means of genetically‐analyzed isoenzymes as markers. This is demonstrated by examples.
Genetic Variation for Seed Yield in Perennial Ryegrass (Lolium perenne L.)
Authors: Elgersma A.
Published: April 2006

In perennial ryegrass seed yield is low and unreliable and little is known about the seed‐yielding capacity of different cultivars. Therefore, genetic variation for seed yield was studied for therefore, genetic variation for seed yield was studied for three years at two locations. Twelve trials consisting of drilled plots of nine diploid, late‐flowering cultivars in four replications were harvested for seed. Significant gentic differences for seed yield and seed weight weight were detected. The ranking of the cultivars for seed yield differed from that for seed weight. The levels of seed yield and seed weight were affected by such environmental factors as year, soil type and crop production year, but interactions of these factors with cultivars were generally not significant. Variation in seed yield was more related to variation in seed number than to variation in seed weight. There were no significant cultivar differences for yield stability. The highest yielding cultivar was superior over a wide range of environments and the seed yield of the poorest cultivar was on average only 64% of that of the best cultivar.
Inheritance of Resistance to Downy Mildew (Peronospora destructor [Berk.] Casp.) from Allium roylei Stearn in the Backcross Allium cepa L. × (A. roylei ×A. cepa)
Authors: Kofoet A. , Kik C. , Wietsma W. A. , de Vries J. N.
Published: April 2006

Allium roylei Stearn and both reciprocals of the interspecific hybrid between Allium cepa L. and A. roylei displayed no symptoms of Peronospora destructor (Berk.) Casp. after artificial or natural inoculations, whereas A. cepa was susceptible. In the offspring from the backcross A. cepa× (A. roylei ×A. cepa) resistant and susceptible plants segregated after artificial inoculations, fitting a 1: 1‐ratio. This suggests that resistance is controlled by a single, dominantly‐inherited locus (designated Pd1) from the nuclear genome of A. roylei. During a severe epidemic in the field, plants from the same backcross segregated resistant and susceptible individuals in a 3: 1‐ratio. Escapes may explain the deviation from the 1: 1‐segregation, but the presence of a second resistance locus segregating independently from Pd1 cannot be excluded, implicating possible differences in virulence between populations of P. destructor. The occurrence in the backcross offspring of plants having a morphology similar to A. cepa without showing symptoms of downy mildew opens perspectives for breeding P. destructor‐resistant onion varieties.
Inheritance of Partial Resistance to Net Blotch in Barley
Authors: Arabi M. I. , Sarrafi A. , Barrault G. , Albertini L.
Published: April 2006

Reciprocal crosses were made between 9 different barley genotypes with high genetic variability for net blotch resistance. Parents and 72 F1 plants were used to determine the inheritance of partial resistance to net blotch. Four experiments, one in a growth chamber on seedlings and 3 others in the field on adult plants, were undertaken using a randomised complete block design. An isolate of net blotch from local cultivars was used for inoculation. Non‐inoculated plants of one of the field experiments were used for the detached leaf test in petri dishes.

Results show that the cultivars ‘Banteng’, and ‘Arrivate’, the Ethiopian line CI 5791, and the Syrian line 79 SIO‐10, had a high partial resistance in all experiments. Diallel analysis showed high significant general and specific combining ability when maternal and reciprocal effects were not significant. As the resistance genotypes have a high additive genetic effect, they could be successfully used for breeding purposes.
Dissection of the Brassica nigra Genome by Monosomic Addition Lines
Authors: This P. , Ochoa O. , Quiros C. F.
Published: April 2006

Hyperploid derivatives of Diplotaxis erucoides × Brassica nigra hybrids were used to extract seven out of the eight possible monosoinic addition lines for B. nigra (genome B). The fertility and transmission of the lines varied depending on the added chromosome. However, these parameters were high enough to assure the maintenance of the addition lines. Although no phenotypic changes were observed, the plants carrying extra chromosomes were slower in development than diploid D. emcoides. Each of the B. nigra chromosomes was recognizable cytologically by size and heterochromatin distribution. Seven of these were characterized by a series of isozymes and RFLP markers. Ribosotnal DNA sequences were detected in two independent B. nigra chromosomes. Two probes disclosed fragments dispersed in more than one chromosome.
Agronomic Performance of Hexaploid Wheat Lines Derived from Direct Crosses between Wheat and Aegilops squarrosa1)
Authors: Cox T. S. , Hatchet J. H. , Gill B. S. , Raupp W. J. , Sears R. G.
Published: April 2006

Direct introgression of genes from diploid Aegilops squarrosa L into hexaploid wheat (Tnticum aestivumL.) is an efficient way of developing stable, hexaploid lines with unique, useful genes. 39 such lines derived front direct crosses to determine the effects of Ac. squarrosa germplasm were field‐tested on productivity. Whereas some lines were agronomically inferior to the recurrent parent, others periormed at an equall or better level. In addition to the larget traits (Hessian‐fly and leaf‐rust resistance), other traits, including soilborne‐mosaic‐virus resistance and protein concentration, were improved.
Medium‐Genotype‐Interaction on Androgenetic Haploid Production in Wheat
Authors: Fadel F. , Wenzel G.
Published: April 2006

The present study investigates the effects of media on the rate of green plantlet formation from anther cultures of five different winter and spring wheat cultivars. An increased number of embryos and calli were produced on Ficoll‐containing liquid potato‐2 medium, whereas the addition of 0.2 M/l maltose increased the rate of regeneration. The genotypes had strong effect on the formation of plantlets, but the developed procedure allows also the regeneration of recalcitrant genotypes. On the best medium sequence, a total of 2430 anthers over all genotypes were plated which developed 1325 macroscopic structures (55 %) of which 159 green plants have developed, i.e. 12 % from the structures and 7 % from the plated anthers, respectively.
Production of Brassica napus × Raphanobrassica Hybrids by Embryo Rescue: An Attempt to Introduce Shattering Resistance into B. napus
Authors: Agnihotri Abha , Shivanna K. R. , Raina S. N. , Lakshmikumaran Malathi , Prakash Shyam , Jagannathan V.
Published: April 2006

Intergeneric hybridization is one of the effective methods to broaden the genetic base of cultivated species. Raphanus sativus, a member of the subtribe Raphaninae, has very hard pods at threshing time. In an attempt to transfer shattering resistance to Brassica napus, Raphanobrassica was used as the male parent in crosses with Brassica napus. Plantlets were obtained by embryo rescue and were further multiplied in vitro by micropropagation of nodal segments. Morphology, cytology and DNA analysis confirmed the hybrid nature of these plants. They were backcrosscd with Brassica napus and the progeny was raised. Plants of BC1 and BC2 generations showed wide variation in morphology, chromosome number and pollen fertility. Some of the plants showed up to 95 % pollen fertility and resistance to shattering, indicating the potential for developing B. napus with resistance to shattering.
An Analysis of Seed Development in Pisum sativum. XIII. The Chemical Induction of Storage Product Mutants
Authors: Wang T. L. , Hadavizideh A. , Harwood A. , Welham T. J. , Harwood W. A. , Faulks R. , Hedley C. L.
Published: April 2006

In an attempt to generate more variation of the type represented by the rugosus loci, r and rb, putative seed development mutants have been isolated from peas (Pisum sativum L.) following chemical mutagenesis of a round‐seeded (RRRbRb) genotype. The populations segregating for wrinkled seeds at the M3 generation were examined for their starch, lipid and protein content. The starch content of the wrinkled‐type variants was between 0 and 55 % with an amylose content between 0 and 80 %, compared with 51 % and 30 %, respectively, for the round‐seeded parent. When the range of compositions of the wrinkled‐type seed was grouped, the values indicated that similar phenotypic groups to the wild type (RRRbRb) and the rugosus types (rrRbRb, RRrbrb and rrrbrb) existed in the population. The lipid content of the putative mutants supported this conclusion. Furthermore, some of the values for starch content and composition, and for lipid content indicated that new mutants had been induced. The material represents the first report on chemically‐induced mutants of legumes with altered storage product composition.
Genetic Analysis of Isozyme Loci in Chives (Allium schoenoprasum L.)
Authors: Eickmeyer F. , Primus‐Kopfer Susanne , Wricke G.
Published: April 2006

The inheritance ot nine isozyme systems in selfed progenies of chives was studied elcctrophoretically. The isozyme systems studied were malate‐dehydrogenase (MDH), phosphoglucoisomerase (PGI), triosephosphate‐isomerase (TP1), diaphorase (D1A), menadione‐reductase (MDR), esterase (EST), glutamate‐oxalacetate‐transaminase (GOT), hexokinase (HK) and superoxide‐dismutase (SOD). Segregation results of Goodness‐of‐Fit tests against the expected 1:2:1 and 3 : 1 ratios for codominant and dominant inheritance, respectively, led to the identification of 16 isozyme loci whose banding patterns are given in this paper. The first results on linkage relationships between isozyme loci and between the Mdr‐3‐locus and a male sterility gene are given. These results and further studies will be used to mark important characters in chives.
Micropropagation of Recessive Determinate Genotypes of Buckwheat (Fagopyrum esculentum Moench.) as an Alternate Approach to Uniform Seed Production
Authors: Neškovič M. , Vintekhaiter B. , Miljuš‐Djukič J. , Ghalawenji N.
Published: April 2006

Dissected apical buds of determinate buckwheat seedlings were cultured on a medium with high BAP to IAA ratio, and clones of micropropagated plants were established. Regenerated plantlets (R1) were transferred to a greenhouse and grown to maturity. All plants of this R1 generation had terminal inflorescence typical for the determinate type. Sixty eight selected R1 plants, belonging to 6 clones (3 pin and 3 thrum), were allowed to cross‐pollinate and 643 seeds were collected. In a sample of 100 seedlings belonging to the R2 generation, all plants again had the characteristic determinate growth habit with no signs of segregation.
Effects of Growth Regulators and Genotypes on Callus and Embryoid Induction from Maize Anther Culture *
Authors: Hongchang M. , Liang G. H. , Wassom C. E.
Published: April 2006

Fifty genotypes and ten growth‐regulator combinations were used in two experiments (I and II) to investigate genotype and hormonal effects on production of callus and embryoids via anther culture in maize (Zea mays L.). Hormonal effects across all genotypes were not significant in either experiment. However, highest callus‐induction frequencies in both experiments occurred on YP basal medium plus 2,4‐D at 2.0 mg 1−1, and kinetin at 1.5 mg 1−1 indicating that this combination was more effective than others. Genotypic differences in callus or embryoid induction across all media were significant. The most responsive genotypes in experiment I were single‐cross hybrids Yuanwu × 592 and K727 × K305, which produced 18.3 and 6.7 % calli, respectively, with their appropriate media. The most responsive entry in experiment II was CIMMYT Pool 29, which produced 15.0 % calli on appropriate medium and an average of 10.0 % calli across 10 media. Twenty‐three plantlets was regenerated from this study. Most of them developed embryogenically.
Shoot Regeneration from Anther Culture of Sunflower (Helianthus annuus) and Some Interspecific Hybrids as Affected by Genotype and Culture Procedure
Authors: Gürel A. , Nichterlein K. , Friedt W.
Published: April 2006

Anther culture has been demonstrated to be an applicable technique for the development of doubled haploid, i. e. homozygous lines of many crop species. In some species, androgenetic doubled haploids have already been shown to be a useful tool for breeding. However, anther culture results in sunflower have been rather unsatisfactory up to now.

As in other species, anther culture response of sunflower (Helianthus sp.) is strongly affected by physical, nutritional, physiological and genetical factors. By testing a number of different culture parameters, i. e. donor plant stages, culture media and conditions, and appropriate schedule could be worked out for the successful regeneration of shoots – at least for a number of sunflower lines and interspecific hybrids.
Components of Visual Selection in Early Clonal Generations of a Potato Breeding Programme
Authors: Neele A. E. F. , Nab H. J. , Louwes K. M.
Published: April 2006

In the first two clonal generations of a potato breeding programme, clones are visually selected for ‘plant appearance’. Selection for plant appearance based on unreplicated small plots is unreliable, due to significant genotype × environment interaction and high error variance. In order to improve the selection efficiency, component traits of plant appearance were identified and the effect of selection for these components was studied. Tuber yield was found to be the principal component of plant appearance while stolon length and tuber appearance contributed significantly, but to a lesser extent. Tuber yield had a higher heritability than plant appearance. Characters determining the appearance of stolons and tubers were found to have equal or lower heritabilities than plant appearance at 80 days after planting and somewhat higher heritabilities than plant appearance at 145 days after planting. Hence, since the expected and observed selection responses of the component characters have been found to be equivalent to that of plant appearance, selection for plant appearance cannot be improved upon by separately selecting for characters like tuber yield and tuber appearance.
Plant Regeneration and Genetic Variability from Tissue Cultures of Sunflower (Helianthus annuus L.)
Authors: Pugliesi C. , Cecconi F. , Mandolfo A. , Baroncelli S.
Published: April 2006

Adventitious buds were induced from in vitro culture of sunflower (Helianthus annuus L.) cotyledons. Four inbred lines (G1, G2, G3 and HA89), an open pollinated variety (‘Argentario’) and two hybrids with specific genetic markers were used. Cotyledons were cultured in vitro on MS medium (Murashlge and Skoog 1962) containing various concentrations of kinetin and indole 3‐acetic acid (IAA). The quantitative interactions between auxin and cytokinin, the age of the cotyledons and the 2,3,5‐triiodobenzoic acid (TIBA) treatments have been found to influence shoot regeneration. The plantlets, after rooting, were successfully established on soil. Qualitative variation was noted in self‐pollinated progeny of plants regenerated from culture of two inbreds. Chimerism in regenerated plants was indicated by sectoring of the genetic markers. Some culture‐induced variant phenotypes were similar to known spontaneous mutation in sunflower but others have been not yet described. Preliminary data indicate that most of them may have single‐gene recessive inheritance.
Protoplast Fusion in the Genus Medicago and Isoenzyme Analysis of Parental and Somatic Hybrid Cell Lines
Authors: Pupilli F. , Arcioni S. , Damiani F.
Published: April 2006

Leaf mesophyll protoplasts of Medicago arborea (2n = 32) were electrofused with cell suspension and/or callus protoplasts of Medicago sativa. Heterokaryons were identified in agarose beds by their dual fluorescein isothiocianate—chlorophyll fluorescence and their coordinates were recorded. Hybrid minicalli were manually picked up and grown first in nurse culture and then in callus induction medium. Hybrid nature of the selected calli was confirmed by isoenzyme analyses. In order to verify whether morphogenesis of somatic hybrid calli was affected by cell incompatibility, mesophyll and cell suspension protoplasts, derived from the same plant of M. sativa with high embryogenic capacity, were fused. Only callus tissues derived from mesophyll protoplasts retained the highly embryogenic character of the M. sativa genotype, while hybrid cell lines were non‐morphogenic and showed isoenzyme patterns similar to tissues derived from cell suspension protoplasts. The achievement of somatic hybrid plants in the genus Medicago is discussed.
Cytological and Morphological Characterization of Pisum sativum and Pisum fulvum Tetraploids
Authors: Errico A. , Conicella C. , Taliercio U.
Published: April 2006

Two colchicine‐induced tetraploid lines, one belonging to Pisum sativum and the other to the wild species Pisum fulvum, were compared with their corresponding diploids and among themselves for chromosome number, meiotic behaviour and for pollen and pod fertility. For both lines, five generations were analyzed; the tetraploid level was maintained throughout the generations. In P. fulvum, aneuploids with 27, 29 and 30 chromosomes were observed, while in P. sativum aneuploids with 29 chromomes were found. Meiotic analysis evidenced a higher number of quadrivalents and a lower number of univalents in P. fulvum. This particular chromosomal behaviour may also have been responsible for determining the higher pollen and pod fertility in P. fulvum. Wild species of this genus seem to have better tolerance for ploidy variations.
Quantitative Genetic Analysis of Traits in Avocado Cultivars *
Authors: Lavi U. , Lahav E. , Genizi A. , Degani C. , Gazit S. , Hillel J.
Published: April 2006

This research is aimed at quantitative genetic analysis of several avocado traits and cultivars. The experimental material consists of our avocado breeding project in which data were collected from several crosses as well as selfings of cultivars. Parenthood was determined by isozymes and the seedling progenies were assessed for eight traits. A biometrical genetic approach for analysis of this breeding project is presented. Genetic profiles of the traits and cultivars were detailed by several characteristics: level of heterozygosity and dominance deviation, dominance of alleles, dominance direction, general evaluation of additive and non‐additive genetic variance, maternal inheritance, and allelic differences among the various cultivars in major genes controlling the same quantitative trait. Five avocado cultivars: ‘Fuerte’, ‘Hass’, ‘Ettinger’, ‘Tova’, and ‘Rosh‐Hanikra’, were characterized separately for each trait. Practical conclusions for the breeder regarding economically important quantitative traits are discussed.
Inheritance of Resistance to Yellow Mosaic Virus in some Vigna Species
Authors: Pal S. S. , Dhaliwal H. S. , Bains S. S.
Published: April 2006

Inheritance of resistance to Yellow Mosaic Virus (YMV) was studied in crosses of mungbean, black‐gram and their interspecific crosses with Vigna sub‐lobata. Resistance to YMV was recessive in the three Vigna species. The segregation ratios in F2 and back crosses indicated that the resistance was digenic recessive in the crosses of mungbean and in interspecific crosses of mungbean with blackgram and Vigna subiobata but YMV resistance was monogenic recessive in blackgram crosses.
Identification of the Putative Cytoplasmic Donor of a CMS System in Brassica juncea
Authors: Pradhan Akshay K. , Mukhopadhyay Arundhati , Pental Deepak
Published: April 2006

Chloroplast (cp) and mitochondrial (mt) DNA restriction profiles of a cytoplasmic male sterile (CMS) line of Brassica juncea and its maintainer line were compared and found to be markedly different. Comparison of cpDNA restriction profiles of fifty different species of genus Brassica and some allied genera showed that the cpDNA profiles of CMS lines were similar to that of B. tournefortii for twenty different restriction endonucleases. This CMS system is thus not of spontaneous origin as reported earlier, but is alloplasmic in nature. Comparison of restriction profiles of mtDNA of B. tournefortii and CMS lines revealed some differences which might either be due to changes in DNA pattern during the transfer, or, due to the cytoplasm coming from a B. tournefortii line different from the one used in this study.
Development of B‐Genome Chromosome Addition Lines of B. napus Using Different Interspecific Brassica Hybrids
Authors: Struss D. , Bellin U. , Röbbelen G.
Published: April 2006

By interspecific hybridization within the genus Brassica, trigenomic haploids were produced and back‐crossed four times with B. napus, variety ‘Andor’. From this material, monosomic B‐genome chromosome addition lines were selected with the extra chromosome derived from three different B‐genome sources, i.e., B. nigra (BB), B. carinata (BBCC), and B. juncea (AABB). After selfing and/or microspore culture, disomic addition lines were obtained. Meiotic behavior was studied of the trigenomic hybrids, the pentaploid BC1 plants, and the monosomic addition lines. The addition lines were shown to possess cytological stability and good fertility.
Intrapopulation Recombination for 15N‐Determined Dinitrogen Fixation Ability in Common Bean
Authors: St.Clair D. A. , Bliss F. A.
Published: April 2006

The quantity of N2 fixed in common bean (Phaseolus vulgaris L.) is a quantitatively inherited trait that shows sufficient genetic variability for improvement through breeding, but there is little information on gain from selection for 15N‐determined N2 fixation ability. The objective was to determine whether intrapopulation recombination and selection could be used to improve N2 fixation. Four agronomically acceptable lines were selected, based on their acetylene reduction‐determined N2 fixation ability, from an inbred backcross (IB) line population created from a cross between the high N2‐fixing donor parent ‘Puebla 152’ and a commercial, low N2‐fixing recurrent parent ‘Sanilac’. These four IB lines were intercrossed, advanced to the F3, and the six resulting F3 populations with 25 F3 families per population were evaluated for N2 fixation in a low‐N field using 15N‐depleted (NH4)2SO4. The six F3 population means differed significantly and were superior to ‘Sanilac’ for N2 fixation ability and yield, indicating significant improvement over ‘Sanilac’. Four F3 population means were similar to ‘Puebla 152’, indicating selection advance towards high N2 fixation while retaining favorable agronomic characteristics. Fifty percent of the F3 families were superior to ‘Sanilac’ for N2 fixation and one family exceeded ‘Puebla 152’, indicating that intrapopulation recombination produced improvement of 15N‐determined N2 fixation.
Homeology Between the Chromosomes of Avena macrostachya and the Avena C Genome
Authors: Pohler W. , Hoppe H.‐D.
Published: April 2006

To gain more information about the widely unknown genome constitution of the taxonomically and agronomically interesting wild oat Avena macrostachya, this tetraploid species was crossed (as the pollinator) with several diploid Avena species. Hybridization failed with A. strigosa (As As), A. hirtula (As As), and A. longiglumis (A1 A1), but succeeded with A. atlantica (As As), A. prostrata (Ap Ap), and A. pilosa (Cp Cp). The output of hybrids and the vitality of the F: plants were highest in the combination A. pilosa×A. macrostachya. Hybrids from this cross relatively frequently showed trivalents at metaphase I as compared to the nearly consistent formation of seven univalents and seven bivalents in hybrids with the A genome species A. atlantica and A. prostrata. Altogether, the results confirm an auto‐ploid origin of A. macrostachya and demonstrate that among the two known basic genomes A and C of the genus Avena only the latter exhibits considerable homeology to the A. macrostachya genome.
The Transfer of Resistance to the Russian Wheat Aphid from Triticum monococcum L. to Common Wheat
Authors: Potgieter G. F. , Marais G. F. , Du Toit F.
Published: April 2006

Two Triticum monococcum accessions were found to be highly resistant to the Russian wheat aphid. An attempt was made to transfer the resistance to common wheat through direct hybridization or by using bridge species. In each of the four crossing strategies tried, a gradual loss of resistance occurred as hybrids with higher ploidy levels were obtained. It appeared that the level of resistance observed was directly proportional to the ratio of the Triticum monococcum genome relative to other genomes. This would indicate suppression of the resistance gene(s) by the added genomes or dilution of its product(s) by those of homoeoloci. The degree of protection afforded by the gene(s) at the hexaploid level may prove to be small. Plants suspected to be homozygous for the resistance gene(s) were identified; however, further backcrossing to common wheat will be required to improve their agronomic types and meiotic regularities.
The Gene Pools of the Grasspea (Lathyrus sativus L.)
Authors: Yunus A. G. , Jackson M. T.
Published: April 2006

Interspecific hybridization between the grasspea, Lathyrus sativus, and 15 wild species in Section Lathyrus is reported. Only two species, L. amphicarpos and L. cicera produced viable F1 hybrids with low fertility when crossed with L. sativus as male parent. Crosses with six other species produced pods following pollination when L. sativus was the male, but seedlings were inviable, seeds did not germinate or pods were empty or had totally shrivelled seeds. When L. sativus was the female parent, only one cross with L. gorgoni produced an F1, but the seedling was inviable. The germplasm resources of the grasspea are identified, with L. amphicarpos and L. cicera placed in the secondary gene pool and the other species in the tertiary gene pool. The definition of these germplasm resources is discussed in terms of grasspea improvement through plant breeding.
Outcrossing Rates of Experimental Populations of Cuphea lanceolate
Authors: Knapp S. J. , Tagliani L. A. , Liu B.‐H.
Published: April 2006

Outcrossing rates of Cuphea lanceolata Ait., a new Dilseed crop, have not been estimated; however, this species is known to be insect‐pollinated, self‐compatible, and autosterile. We used five allozyme loci and the mixed mating model to estimate the outcrossing rates of experimental populations of Cuphea lanceolata Ait. grown at Corvallis, Oregon in 1987 and 1988. Populations were grown using densities of one and 27 plants m−2. Multilocus out‐crossing rate estimates of populations grown at low and high density ranged from 0.61 to 0.85 and 0.93 to 0.94, respectively. Density caused differences may be caused by differences in pollinator movement. In open plantings, e.g., space‐plant nurseries, selfing rates are increased by increased within plant pollination by bumblebees, the primary pollinators of C. lanceolata in temperate zones. The movement of pollinators between plants is enforced in dense plantings. We found C. lanceolata is predominantly al‐logamous, but selfing rates as great as 39.0 % were observed among space‐plants; thus, the progeny of an open‐pollinated individual plant grown in this type of nursery is a mixed half‐sib and S1 family. Maximum outcrossing can be achieved by using dense plantings.
Two Medium Chain Fatty Acid Mutants of Cuphea viscosissima
Authors: Knapp S. J. , Tagliani L. A.
Published: April 2006

Cuphea viscosissima Jacq. is an herbaceous annual dicot indigenous to the U.S. This species is being developed as a new oilseed crop and commercial source of medium‐chain fatty acids (MCFAs). In this paper, the phenotypes and genetics of the mcm‐1 and cpy‐1 mutations of C. viscosissima are described. These mutations affect the percentages of fatty acids of seed storage lipids. They were induced by treating seeds with 0.04 M ethyl methanesulfonate for 5 h. Observed segregation ratios for these mutations were not significantly different from expected ratios for codominant genes. The mcm‐1 mutation eliminates 95.0 % of wildtype MCFAs — caproic (C6: 0), caprylic (C8: 0), and capric (Cio: 0) acid percentages are decreased from 0.8 to 0.0 %, 20.7 to 0.5 %, and 68.6 to 6.7%, respectively. The cpy‐1 mutation decreases C6: 0 and C8: 0 from 0.9 to 0.0 % and 19.8 to 3.9 %, respectively, whereas it increases C12: 0 and C14: 0 from 2.2. to 14.3 % and 0.8 to 7.4 %, respectively.
Production of a Trisomic Series in Hordeum vulgare cv. ‘Golden Promise’ and its Use in Locating a Recessive Chlorina Gene
Authors: Pickering R. A.
Published: April 2006

A trisomic series was produced from a triploid plant of barley (Hordeum vulgare L. cv. ‘Golden Promise’) derived from tissue culture. Its characteristics are briefly described and compared with two trisomic series reported previously. Trisomic number 1 performed poorly under glasshouse conditions. Number 2 failed to set any seed after selfing and must be maintained by pollinating with ‘Golden Promise’. The series was subsequently used to locate a recessive chlorina gene on barley chromosome 3.
Biomass Yield — A Topical Issue in Modern Wheat Breeding Programmes
Authors: Damisch W. , Wiberg Anneliese
Published: April 2006

Plot experiments were made involving seven winter wheat varieties to study growth rate and biomass yield in relation to grain yield and yield stability. The results obtained with ‘Apollo’ show that it is possible to boost grain yield and obtain simultaneously an adequate yield stability by increasing the biomass potential until anthesis and maintaining high growth rates in the grain‐filling period. Higher grain yields were likewise reached by merely increasing the growth rate after anthesis at an equal or lower biomass potential at anthesis, but yield stability was lower then.
Genetic Diversity of the Date Palm (Phoenix dactylifera L.) from Algeria Revealed by Enzyme Markers
Authors: Bennaceur M. , Lanaud C. , Chevallier M. H. , Bounaga N.
Published: April 2006

Analysis of the enzymatic polymorphism of the date palm, Phoenix dactylifera L., was undertaken to evaluate the genetic variability of Algerian cultivars. Seven enzyme systems (alcohol dehydrogenase, diaphorase, aspartate aminotransaminase, acid phosphatase, endopeptidase, leucine aminopeptidase and phosphoglucomutase) were visualized by electrophoresis. Genetic hypotheses appear to show 7 polymorphic loci and 16 alleles were counted. The study of diversity showed a high percentage of polymorphic loci, strong heterozygosity and considerable genetic diversity. The study shows that genetic variability is greater in the cultivars in the western regions (Saoura‐Touat) than in the eastern regions (Rhir‐Zibans). An identification key was devised and nearly 65% of the cultivars studied were identified from 5 enzyme systems.
Screening by PCR for Defined DNA Sequences in Minimal Amounts of Barley Tissue
Authors: Dehmer K. J. , Graner A. , Wenzel G.
Published: April 2006

The potential use of the polymerase chain reaction (PCR) in screening plants for defined DNA sequences was demonstrated in barley (Hordeum vulgare). As templates for PCR, purified DNA as well as DNA from crude cell extracts of different barley tissues can be used. Specific synthesis of the target sequence was possible in both cases. Under optimal conditions, as little as 20 copies of the barley genome, i.e., 20 cells, were sufficient for successful amplification. This amount of DNA is equivalent to significantly less than 1 mg of fresh tissue.
Development of RFLP Markers for Barley
Authors: Jahoor A. , Backes G. , Graner A. , Herrmann R. G. , Fischbeck G.
Published: April 2006

A PstI‐based genomic library from barley DNA was screened for RFLPs in the three relatively‐distant cultivars ‘Alexis’ (2‐row spring type), ‘Igri’ (2‐row winter type) and ‘Mammut’ (6‐row winter type), digested with BamHI, EcoRI and HindIII. 50 % of the 108 DNA fragments studied represented single‐copy sequences, 29 % low‐copy and 21 % repetitive sequences. The DNA probes were assigned to discrete barley chromosomes with the aid of wheat/barley addition lines. 80 % of the single‐ and low‐copy sequences hybridized with both barley and wheat DNA, whereas most repetitive sequences gave signals only with barley DNA.
Correlation between Potato Clones Grown in vivo and in vitro under Sodium Chloride Stress Conditions
Authors: Morpurgo R.
Published: April 2006

Salinity is one of the most serious and widespread agricultural problems resulting in losses of yield and arable land. One strategy available to cope with saline soil is to choose salt‐tolerant crops or to select salt‐tolerant cultivars within a crop. Difficulties in breeding for salt tolerance arise from its polygenic control and from the variable salt composition and distribution in the soil. An in vitro approach for screening large amounts of parental material is suggested and the present results confirm previous work conducted on in vitro response of the potato to a high level of sodium chloride. Furthermore, a highly significant correlation was found between in vitro growth parameters and field performance of ten potato clones.
Inheritance of Temperature‐Induced Pseudocompatibility in Rye
Authors: Gertz A. , Wricke G.
Published: April 2006

The differences between pseudocompatible seed produced by selfing self‐incompatible plants of rye (Secale cereale L.) at high temperatures were investigated. The isozyme loci Prx7 and β‐Glu which are linked to the two self‐incompatibility loci S and Z, were used as markers. Different alleles of S and Z strongly influenced the pseudocompatibility. For the locus S at 30°C a scale of varying efficiency of the S alleles was found. Furthermore, it proved possible to select one population with increased and one with decreased pseudocompatibility at high temperatures. The population with high pseudofertility was still incompatible under normal temperature conditions. Such selected material facilitates the production of inbred lines of self‐incompatible rye material, which can be a useful tool in an efficient rye breeding programme.
Efficiency of Early Selection for Yield Performance in Wheat
Authors: Peters B. , Spanakakis A. , Weber W. E.
Published: April 2006

Selection for yield in early generations is difficult, mainly due to a shortage of seed. In the breeding company Fr. Strube the breeder uses three‐way crosses and first selects for yield between F2′‐derived lines in the F4′. The generations are called F1, F2′, etc., because the first generation is already segregating. The efficiency of this selection was checked in the F5′ and F6′. For this purpose F3′‐derived progenies, corresponding to poor and good yielding bulks in F4′, were selected. In later generations the average yield of the group of strains with good yield in the F4′ was 4 % (F5′) and 3 % (F6′) higher, respectively, than the mean of the strains with low yield in the F4′. Strains with very low yielding potential can easily be discarded in the F4′. The risk of discarding lines with a very high yield is minimal. Selection for yield in the F4′ was as effective as in the F5′. The importance of testing F2′‐derived bulks in the F4′ is not only based on the assessment of yield but also on the possibility of reliable intensive selection through recording visual characters (height, resistance against diseases) in a second environment in parallel to the single plant progenies.
Cytoplasmic Systems in Different Male‐Sterile Lines of Rice
Authors: Pradhan S. B. , Ratho S. N. , Jachuck P. J.
Published: April 2006

In order to characterize the cytoplasmic system in seven cytoplasmic‐genic male‐sterile lines (CMS; A lines) of rice, viz., V 20A, ‘Zhenshan 97A’, IR 46831A, ‘Madhu A’ (cms‐WA), ‘Yar‐Ai‐Zhao A’ (cms‐Gam), ‘Pankhari 203A’ (cms‐TN) and Wu 10A (cms‐bo) and their isonuclear maintainers (B lines), all possible crosses were made between CMS lines and maintainers (A × B) as well as between the maintainers themselves (B × B). Based on F1 pollen and spikelet fertility the CMS lines V 20A, ‘Zhenshan 97A’, IR 46831 A, ‘Madhu’ A possessing cms‐WA cytoplasm were found to be genetically different from ‘Pankhari 203A’ (cms‐TN), Wu 10A (cms‐ bo) and ‘Yar‐Ai‐Zhao A’ (cms‐Gam) cytoplasms. Cms‐bo and cms‐TN cytoplasms appeared to be identical. Since the cytoplasms of the A lines are different from those of the B lines, the nuclear genes operating to cause the sterility might also be different in (A × B) and (B × B) crosses.