bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of powdery‐mildew‐resistance genes in common wheat (Triticum aestivum L. em. Thell.). V. Old German cultivars and cultivars released in the former GDR
Authors: Lutz J. , Katzhammer M. , Stephan U. , Felsenstein F. G. , Oppitz K. , Zeller F. J.
Published: April 2006

A total of 59 old wheat cultivars grown in Germany prior to 1960 were tested for mildew response using a collection of 12 differential isolates of Erysiphe graminis DC f. sp. tritici Marchal (Blumeria graminis (DC) Speer f. sp. tritici). Nineteen cultivars did not possess any major resistance gene and 25 were characterized by susceptible or intermediate responses. Fifteen cultivars revealed isolate‐specific response patterns that could not be attributed to known major resistance genes or gene combinations. Many of the old German cultivars inherited a mildew‐resistance gene from the Canadian cultivar ‘Garnet’ which is tentatively designated M1‐Ga. Cultivars ‘Bretonischer Bartweizen’ (designated M1‐Br) and ‘Adlungs Alemannen’ (designated M1‐Ad) appeared to carry unknown resistance genes.

Among 18 winter wheat cultivars released in the former GDR. eight showed susceptibility to all isolates used. Cv. “Borenos” carries resistance gene Pm3c. Five cultivars possess gene Pm4b. two cultivars gene pm5 and one cultivar a combination of genes Pm2 and Pm4b. Cultivar ‘Zentos’ was resistant to almost all isolates used. Its resistance might be conditioned by different unknown major resistance genes.
Grain quality and yield characteristics of D‐genome disomic substitution lines in ‘Langdon’ (Triticum turgidum var. durum)
Authors: Liu C.‐Y. , Rathjen A. J. , Shepherd K. W. , Gras P. W. , Giles L. C.
Published: April 2006

Sets of D‐genome disomic substitution lines of ‘Langdon’ (Triticum turgidum var. durum) were used to study the effect of chromosome substitutions on grain yield and flour technological properties.

In general, the substitution of any D‐genome chromosome had a detrimental effect on grain yield and growth vigour (some lines were sterile). SDS‐sedimentation, SE‐HPLC and two‐gram mixograph procedures were used to measure dough strength of the lines studied. Significant correlations were observed between protein concentration and grain yield and other quality parameters such as SDS‐sedimentation value, the proportion of glutenin, dough mix time and peak resistance. Most of the quality characters were highly correlated with each other.

Substitution of chromosomes 1D, 5D, 2D and 7D resulted in positive responses to SDS‐sedimentation values, but only chromosome 1D had positive effects on the proportion of peak 1 (P1%), measured by SE‐HPLC. Besides the major influence of chromosome 1D on three major mixograph parameters (mixing time, peak resistance and resistance breakdown), chromosome 5D also exhibited significant effects on these mixing parameters. Principal‐component analysis showed that the predominant effect on durum‐wheat rheological properties was from chromosome 1D, whereas chromosome 5D had a major effect on grain hardness (50%) and increased the whiteness of the flour.
Relationships between different prolamin proteins and some quality properties in durum wheat
Authors: Ruiz M. , Carrillo J. M.
Published: April 2006

The objective of this paper was to study the differences between some prolamin variants coded at the loci Glu‐3/Gli‐1, Glu‐1 and Gli‐A2 and their relative roles in durum‐wheat quality. F3 lines from four durum wheat crosses (‘Abadia’×‘Mexicali’. ‘Oscar’×‘Ardente’, ‘Oscar × Mexicali’ and ‘Alaga’×‘C. of Balazote’) were analysed for gliadin and glutenin composition by electrophoresis. Whole‐grain‐derived samples were analysed for SDS sedimentation (SDSS) value, mixing properties, and contents of protein and vitreousness. The glutenin patterns LMW‐2. LMW‐2− and LMW‐2 (CB) at Glu‐B3/Gli‐B1 were associated with better gluten quality than were LMW‐1 and LMW‐2*. The glutenin subunits LMW4 and LMW3 + 15 at Glu‐A3/Gli‐A1 and HMW‐1 showed better mixing properties than LMW7 + 12, LMW5 and the null phenotype. respectively. The HMW glutenin subunits 20 + 8 at Glu‐B1 showed a negative association with gluten quality, but the rest of the HMW glutenin subunits and α‐gliadins did not show any influence on gluten quality.

Correlations between the results of the SDSS test and the mixograph were highly significant, but no correlation was found between these results and protein and vitreousness contents. The results are discussed in relation to the development of durum wheat varieties with improved qualities.
Genetics of multiple disease resistance in a doubled‐haploid population of barley
Authors: Steffenson B. J. , Jin Y. , Rossnagel B. G. , Rasmussen J. B. , Kao K.
Published: April 2006

The barley accession Q21861 possesses resistance to the stem‐rust (Puccinia graminis f.sp. tritici), leaf‐rust (P. hordei), and powdery‐mildew (Blumeria graminis f.sp. hordei) pathogens. An anther‐culture‐derived doubled‐haploid population was produced from F1 plants from a cross of this accession and the susceptible breeding line SM89010 as a means of rapidly and efficiently determining the genetics of multiple disease resistance. The doubled‐haploid population segregated 1:1 (resistant:susceptible) for resistance to the stem rust pathotype QCC indicating the involvement of a single resistance gene, rpg4. Two‐gene (3:1) and one‐gene (1:1) segregation ratios were observed for resistance to the stem‐rust pathotype MCC at low (23–25°c) and high (27–29°C) temperature, respectively. These different segregation patterns were due to a pathotype × temperature interaction exhibited by rpg4 and Rpg1. another stem‐rust‐resistance gene present in Q21861. One‐gene and two‐gene segregation ratios were observed in reaction to the leaf rust and powdery mildew pathogens. These data demonstrate the utility of doubled haploid populations for determining the genetics of multiple disease resistance in barley.
Genotypic differences in susceptibility to wireworm attack in potato: mechanisms and implications for plant breeding
Authors: Olsson K. , Jonasson T.
Published: April 2006

The influence of different tuber compounds on susceptibility to wire‐worms (Agriotes obscurus) was studied in experiments with 10–13 potato genotypes. Both greenhouse and field experiments showed that the susceptibility to wireworm attack was negatively correlated with the concentration of glycoalkaloids and positively correlated with the concentration of reducing sugars in the outer 2 mm of the tubers. Varietal differences in chlorogenic acid had no effect on susceptibility. Breeding for high levels of glycoalkaloids in the extreme periphery, but very low levels in the rest of the tuber, will protect the tubers from wireworms and yet result in acceptable glycoalkaloid levels for food safety.
Interactions in the pepper‐Phytophthora capsici system
Authors: Ortega R. Gil , Español C. Palazon , Zueco J. Cuartero
Published: April 2006

To analyse interactions in the Phytophthora capsici‐pepper (Capsicum annuum L.) system, three pepper lines (‘Morrón IN1A 224’, ‘PI201232’ and ‘SCM 334’) with various degrees of resistance to P. capsici and three P. capsici isolates with increasing aggressiveness were used. Inoculations were made when plants had 4–6 leaves, either by irrigating the culture substrate with P. capsici zoospore suspensions at increasing concentrations of up to 3 × 105/ml, or by adding mycelial suspension. P. capsici isolate ‘Ca’ was the least aggressive, followd by ‘8303’ and ‘Bl’. The logistic function was appropriate to describing cumulative mortalities of pepper seedlings inoculated with different P. capsici zoo‐spore concentrations. The inoculum concentration required for 50% mortality classified pepper lines as susceptible (‘Morrón INIA224’) and resistant (‘PI201232’ and ‘SCM334’), the former being less resistant than the latter. Isolates ‘Ca’ and ‘8303’ caused very different mortalities both with zoospore and mycelial inoculations, which allowed them to be classified as belonging to two different vertical pathotypes (PO and PI). Isolate ‘Bl’ acted similarly to isolate ‘8303’ when inoculated on ‘Morrón’ and ‘SCM334’, but its behaviour was dependent on zoospore concentration when inoculated on ‘PI201232’. It also proved to be similar to ‘Ca’ using mycelial inoculation. As the case of ‘Bl’ would not be an exception among P. capsici isolates, the two vertical pathotypes PI and PO would be the higher (isolate ‘8303’) and lower (isolate ‘Ca’) limits of a range of aggressiveness. Although there are cases of host‐parasite interaction, absence of interaction seems to be the rule.
Anther‐culture response in different genotypes and F1 hybrids of pepper (Capsicum annuum L.)
Authors: Mitykó J. , Andrásfalvy A. , Csilléry G. , Fári M.
Published: April 2006

An in vitro anther‐culture method has been improved by using young mother plants and by using frequent subcultures, thus increasing the androgenic yield in different Capsicum annuum L. genotypes. An assortment of peppers was used, composed of 15 genotypes (four breeding lines, seven cultivars and four F1 hybrids). A new system for qualifying the androgenic response was established. For use in practical breeding, a minimum of 5 % of plant regeneration was proposed as the criterion for a fair response. Accordingly, one excellent, one good and eight fair responses were identified among the genotypes investigated. As compared to the standard cultivar. 2 genotypes gave a significantly better response, i.e. ‘Fehérözön’ (75.8%) and ‘Szechuan 90716’ (21.0%). In comparative investigations, F1 hybrids, produced from crosses between poor/non‐responsive and responsive genotypes, showed a fair level of response, even the case of a poor response in donor parent. The ploidy level of the resulting plants was determined by flow‐cytometric analysis.
Genetic gains in two selection phases of a wheat‐breeding programme
Authors: Khalil I. H. , Carver B. F. , Smith E. L.
Published: April 2006

Genetic gain in field crops is usually estimated as the collective contribution of several breeding programmes. Critical to an individual breeder, however, is the genetic gain realized within a single programme. Our objective was to quantify per‐annum genetic gains from 1969 to 1993 within two successive phases of experimental line testing in the wheat (Triticum aestivum L.) breeding programme of the Oklahoma Agricultural Experiment Station. Data for grain yield (Phases I and II), volume weight and heading date (Phase II) were analysed according to the procedure developed by St. Martin and McBlain (1991). Genetic gains for grain yield were indistinguishable between phases, averaging 4.6 ± 1.1 and 4.2 ± 1.3% of the control mean across the 24‐year period. Genetic gain for volume weight averaged only 0.2% of the check mean, reflecting lower selection pressure for that trait compared to grain yield. Inconsistent genetic gains in heading date reflect a preference for a window of desirable heading dates rather than difficulties in selecting uni‐directionally for maturity. The absence of a decline in genetic gain in recent years indicates that future improvement in grain yield is likely; however, increased attention must be given to volume weight to maintain US domestic and export standards for hard winter wheat. The statistical procedure was useful in monitoring long‐term trends in genetic gains and identifying gaps in programme efficiency.
Genetic analysis of powdery‐mildew (Erysiphe graminis f.sp. hordei) resistance derived from wild barley (Hordeum vulgare ssp. spontaneum)
Authors: Mastebroek H. D. , Balkema‐Boomstra A. G. , Gaj M.
Published: April 2006

The inheritance of resistance to powdery mildew was investigated in 20 accessions of Hordeum spontaneum and in 20 F4 lines derived from crosses between the variety ‘Aramir’ and 13 accessions of H. spontaneum. Two resistance genes were detected in 17 accessions, and three resistance genes in one accession. In two accessions, only one resistance gene was present. The 20 breeding lines showed a large variation in infection type and infection level. The genetic relationship between the resistance genes detected was investigated in the seven most resistant F4 lines. These F4 lines were divided into three groups which carried different resistance genes. In two lines, the detected resistance gene was shown to be race‐specific.
Variation among progenies of diploid plants regenerated from haploid, microspore‐derived cell‐suspension protoplasts of rice (Oryza sativa L.)
Authors: Mezencev N. , Clément G. , Guiderdoni E.
Published: April 2006

Progenies of 110 diploid R0 plants regenerated from haploid protoplasts derived from microspore callus cell suspension culture of rice (cv. Miara) were evaluated for 6 traits, along with control lines, in a replicated field trial. Complementary post‐harvest observations were carried out for four panicle or grain characters. A wide range of variation was observed for all traits under study among the protoclonal lines. The mean of the protoclonal population was significantly different from that of the control for most traits and 64.5% of the lines differed from the control for at least one field‐evaluated trait. A unidirectional shift towards later‐maturing, taller, and lower‐tillering lines was observed. Of all the lines, 39% were taller than the control by at least 10 cm, 31 % had flowering delayed by at least 5 days, and 13% exhibited significantly longer panicles (P = 0.05). As to the agronomical value of the lines, the variation resulted in a global negative drift although favourable variations were found in a few lines. All but two lines were homogeneous, suggesting that most variations existed in a homozygous form in the R0 plants. R2 lines grown from seeds of 17 R1 protoclonal lines stably inherited the changes and did not segregate, thereby confirming that variations are fixed.
Variation and covariation for quantitative resistance to head blight (Fusarium culmorum) in two testcross series of S2 lines in winter rye
Authors: Miedaner T. , Ziegler D. E. , Geiger H. H.
Published: April 2006

The amount of genetic variation among inbred lines and testcrosses, and covariation between both genetic materials, are of crucial importance for selection efficiency in hybrid breeding. To estimate these quantitative genetic parameters for resistance of winter rye (Secale cereale) to head blight caused by Fusarium culmorum, 88 three‐way cross hybrids, produced by crossing each of 44 S2 Carsten inbred lines with two unrelated Petkus single‐cross testers, were evaluated along with the parental lines over 2 years. Resistance traits were head‐blight rating and grain weight per spike relative to the non‐inoculated control. Significant genotypic variation occurred among lines and in both testcross series. S2 lines displayed considerably more variation than testcross series. Genotype × environment interaction was more marked among the inbred lines, while estimates of heritability were similar for both genetic materials. Testcrosses showed heterosis for head‐blight resistance. No relationship existed between S2 lines and the two testcross series for any resistance trait. This might be caused by an association between inbreeding and Fusarium‐head‐blight susceptibility and different inbreeding depression among the S2 population. The phenotypic correlations between the testcross series were moderate for both traits (r = 0.58, P < 0.01). In conclusion, Fusarium‐head‐blight resistance has to be selected at the respective heterozygosity levels.
Inheritance of anther‐culture response in perennial ryegrass (Lolium perenne L.)
Authors: Madsen S. , Olesen A. , Dennis B. , Andersen S. B.
Published: April 2006

Genetic control of the capacity to respond to anther culture in perennial ryegrass was studied in F1 offspring from crosses between 11 clones selected for anther‐culture response (‘inducers’) and 10 clones selected from breeding material on the basis of good agronomic performance. Large differences in anther‐culture response were observed between the two types of parent, with inducer clones producing an average of 10.7 green plants per 100 anthers, compared with only 0.3 for breeding clones. Hybrid populations produced an average of 2.2 green plants per 100 plated anthers, which is 7.3 times the response of the breeding material. This improvement was mainly due to a 9.4‐fold increase in the percentage of green plants regenerated from hybrid populations to 4.7% compared to an average of 0.5% from breeding clones. Most of the GCA (general combining ability) in the experiment was contributed by the breeding material, constituting 55.8, 100.0 and 36.7% of genetic variation among hybrids for embryo formation, regeneration and green plant percentage, respectively. Any remaining genetic variation among hybrids was predominantly due to SCA (specific combining ability) effects, with percentages of 44.2 and 63.3%, respectively, for embryo and green plant formation. These results are discussed with respect to the possible exploitation of genes controlling anther‐culture response for haploid production in breeding programmes of perennial ryegrass.
Phenotypic differences in transgenic plants of chrysanthemum
Authors: Benetka V. , Pavingerová D.
Published: April 2006

Phenotypic deviations in transgenic plants of chrysanthemum (Dendranthema grandiflora Tzvelev.) cv. ‘White Snowdon’ carrying either whole pTiB6S3 T‐DNA or the GUS gene construct were evaluated. Morphological differences in comparison with the controls were observed not only in regenerated transgenic plants carrying Agrobacterium tumefaciens B6S3 T‐DNA, but also in transgenic plants carrying the GUS gene. The phenotypic changes were stable through several cycles of clonal propagation.
Phenotypic expression of quantitative and qualitative components of partial resistance to powdery mildew (Sphaerotheca fuliginea race 1) in melon (Cucumis melo) germplasm
Authors: Boiteux L. S. , Reifschneider F. J. B. , Pessoa H. B. S. V.
Published: April 2006

A study was conducted to investigate the expression of four components of partial resistance to Sphaerotheca fuliginea race 1 in selected melon (Cucumis melo L.) lines viz. infection frequency, latent period, spore production, and disease‐severity score. Those components were evaluated at two developmental stages of the host: the cotyledon stage and the stage of the first two true leaves. Detached plant parts (disks of cotyledons and true leaves) were inoculated using a vacuum‐operated settling tower. All four components showed significant variation among genotypes, and correlations between components at both developmental stages were large and significant. The line ‘CNPH 83–095’ (without any major resistance gene to powdery mildew) presented the highest level of partial resistance in both vegetative stages for almost all components evaluated. The lines ‘W‐6’ (Pm1Pm1, Pm2Pm2), ‘Cinco’ (Pm1Pm1, Pm2Pm2), and CNPH ‘84–147’ (Pm1Pm1), even though carrying the major gene Pm1 for complete resistance to race 1 of the fungus, showed slight but significant differences for quantitative components of partial resistance at the cotyledonal stage. Different levels of partial resistance may be expressed, even in lines with a major race‐specific resistance gene to powdery mildew, in specific developmental stages of the melon plants.
Purity control of F1‐hybrid tomato cultivars by RAPD markers
Authors: Rom M. , Bar M. , Rom A. , Pilowsky M. , Gidoni D.
Published: April 2006

Randomly amplified polymorphic DNA (RAPD) markers were applied in purity control of hybrid seed production of tomato (Lycopersicon esculentum Mill.). DNA from three commercial F1‐hybrid cultivars and their parental lines was subjected to RAPD screening with 50 primers. Two of four primers which detected polymorphism between the parents tested, generated paternal‐specific RAPDs, enabling a clear distinction to be made between hybrids and their maternal parents. In addition, combination of the polymorphic DNA products generated by these primers exhibited hybrid‐specific patterns, enabling each cultivar to be identified. This result indicates the practical usefulness of RAPD markers in hybrid‐tomato‐seed purity‐control tests and cultivar identification.

The approach is advantageous in its rapidity and simplicity, particularly as an alternative for those cultivars for which lengthy and costly phenotypic tests are currently used.
Selection in vitro for erucic‐acid content in segregating populations of microspore‐derived embryoids of Brassica napus
Authors: Albrecht S. , Möllers C. , Röbbelen G.
Published: April 2006

Microspore culture of Brassica napus under optimized conditions leads to the regeneration of microspore‐derived embryoids that, at the late cotyledonary stage, contain large amounts of storage lipids, equal or similar in composition to those found in seeds of the homozygous donor plants. At that stage, the microspore‐derived embryoids are large enough to allow the dissection of one cotyledon under aseptic conditions and the determination of its fatty‐acid composition. The remaining part of the embryoid can be cultured further and regenerated to give a plant. This offers the possibility of early selection for fatty‐acid composition in segregating populations of microspore‐derived embryoids. In order to verify this hypothesis, embryoids were generated from microspores of F| plants derived from a cross between doubled haploid lines of the low‐erucicacid cv. ‘Duplo’ and the high‐erucic‐acid cv. ‘Janetzki’. The contents of eicosenoic acid (C20: 1) and erucic acid (C22: 1) in the cotyledons and in the seeds derived from plants regenerated from the remaining parts of the embryoids were highly correlated (rs = 0.85**, P = 0.01). This indicates that, in breeding programmes for high erucic acid, the majority of the microspore—derived embryoids can be discarded at an early stage in vitro. Only microspore‐derived embryoids with a high content of C20: 1+C22:1 in the cotyledons need to be transferred to the greenhouse. This report also deals with the addition of abscisic acid (ABA) to the embryoid culture medium to increase the correlation, and discusses the possible application of this system for the selection of high‐oleic or low‐linolenic types in corresponding microspore‐derived embryoid populations.
Spontaneous and induced chromosome doubling in gynogenic lines of onion (Allium cepa L.)
Authors: Campion B. , Perri E. , Azzimonti M. T. , Vicini E. , Schiavi M.
Published: April 2006

The presence of 2,4‐dichlorophenoxyacetic acid (2,4‐D) or naphthaleneacetic acid (NAA) and 6‐benzyladenine (6—BA) in the medium is required to induce an acceptable yield of gynogenic embryos from unfertilized ovary and flower cultures in onion. Four different exposure times of ovary and flower cultures to exogenous growth regulators (15, 30, and 45 days, and the entire culture period) were assayed. The objective was to ascertain the effect of these substances and of their period of application on the formation of gynogenic embryos and on the yield of haploids. An exposure of 15 days was sufficient for ovaries and flowers to be stimulated towards the gynogenic response, whereas, for the remaining period of 30—80 days, the pro‐embryos could easily grow on a growth‐regulator‐free medium. In the gynogenic material obtained, phenotypic differences were visible between genetically independent lines but not between plants within each line, even when they had a different ploidy level (n or 2n). Almost all lines obtained by gynogenesis were sterile. Only a small percentage (1%) became fertile through spontaneous chromosome doubling, and these produced 2—20 seeds each, giving normal plants. The recovery of fertility occurred more often during the generations of bulbils. To exploit this natural propensity towards diploidization in this phase, different amounts and numbers of applications of colchicine were evaluated in two experiments. The treatments corresponding to 10 and 100 mg/1 of colchicine applied for 24h gave the highest number of diploid cells in root tips but no diploidization occurred in the shoot apices. Three days of colchicine treatment at 10 mg/1 produced 46% of plants completely diploid in the shoot apex. The flower fertility of these doubled haploid plants is being evaluated.
Genetic analysis for haploid‐regenerations responses of the hexaploid‐wheat anther cultures
Authors: Moien A. , Sarrafiu A.
Published: April 2006

Genetic variability in response to anther culture was investigated in 49 winter hexaploid wheats, comprising 33 pure lines (F10) derived from a composite cross programme and their 16 parental genotypes. All genotypes were grown in a randomized block design with three replications in a controlled greenhouse. The number of embryoids and total plant regeneration per 100 anthers, as well as the numbers of green and albino plants regenerated per 100 embryoids, were measured.

Significant genetic variability was observed among the 49 genotypes for all the traits studied. All traits showed high heritability. Among the genotypes compared, DC230N and 1BPT‐40 gave the best results for the production of embryoids and IBPT‐78 had the highest value for the production of green plants.

The genotype IBPT‐34 developed a large number of albino plants, and it should be useful as a parent in studies to determine the genetic control of albino plants in wheat.
Types and components of resistance to Fusarium head blight of wheat
Authors: Mesterházy A.
Published: April 2006

Resistance of wheat to Fusarium head blight caused by Fusarium graminearum and F. culmorum was identified in natural epidemics in 1985 and 1987 as well after artificial inoculations (1983–1988 and 1984–1987). Out of 25 genotypes tested, five were identified with no significant difference in head blight scores, but differing significantly in yield after artificial inoculation, i.e. tolerance differences were detected at different resistance levels. Some genotypes that were similar in yield or head blight scores differed in seed infection severity. Genotypes with awns were more susceptible to head blight when tested under natural epidemic condition in the field; but this trait did not influence head blight severity in artificial inoculations. Dwarf genotypes were more severely infected by head blight than tall genotypes under natural conditions, but genotypes of different plant height classes were similarly susceptible after artificial inoculations. In the early generations of a breeding programme resistance measured by visual evaluation of artificial inoculation is the most important way to screen. If selection of dwarf and awned genotypes cannot be avoided, the higher susceptibility caused by awns and dwarfness under natural epidemic conditions can be decreased by a higher level of physiological resistance, as variability in physiological resistance is available. In later generations, traits like percentage of seed infection or tolerance can be identified by additionally measuring yield reduction. Stability of disease reaction appears to be connected with resistance level, the most resistant genotypes are the most stable, and the most susceptible ones tend to have more unstable reactions in different epidemic conditions.
Genetic analysis of powdery‐mildew resistance of a winter‐wheat line, RE714, and identification of a new specific‐resistance gene
Authors: Robe P. , Doussinault G.
Published: April 2006

The winter‐wheat line RE714, resulting from an intergeneric cross between Aegilops squarrosa and Triticum dicoccum, and implying a sister line of ‘Roazon’ (VM4) in its genealogy, was obtained in order to increase the genetic diversity for disease resistance. The aim of this study was to identify and characterize the powdery‐mildew‐resistance gene(s) present in this line at the seedling stage on detached leaves. The comparison of the reaction of the RE714 line and of differential hosts to 24 Erysiphe graminis. f.sp. tritici isolates indicated that only Pm4a, Pm4b and/or Mlar genes could be present and that a new resistance factor, different from all known mildew‐resistance genes, was present in this line. The powdery‐mildew reactions of segregating F2 populations produced evidence that RE714 carries the Pm4b allelic form and a recessive new resistance gene, tentatively designated mlre. While Ae. squarrosa was resistant to most isolates, T. dicoccum was specifically attacked by REV 14‐virulent isolates and was therefore assumed to be the donor of mire. The VM4 parent was confirmed as the Pm4b donor.
Rht1(B. dw), an alternative allelic variant for breeding semi‐dwarf wheat varieties
Authors: Worland A. J. , Sayers E. J.
Published: April 2006

The vast majority of the world's acreage of semi‐dwarf wheat varieties is at present cultivated with varieties carrying one of two genetically similar dwarfing genes, Rht1 and Rht2, derived from the Japanese variety ‘Norin 10’. Near‐isogenic lines have been developed and tested to determine the breeding potential of an allelic variant of Rht1, designated Rht1(B. dw).

Following its introduction into four varietal backgrounds, Rht1 (B. dw) was seen to reduce height by around 25%, to increase the number of grains setting in spikelets and ears by around 20%, to reduce grain weight by 10%, and to increase yields of plants grown under spaced or drilled conditions by about 8%.

When compared to the commercially utilized Rht1 allele, as near isogenic lines in a ‘Mercia’ varietal background, Rht1 (B. dw) gives a significantly greater reduction in plant height, a greater increase in spikelet and ear fertilities, slightly less reduction in 1000‐grain weight, and significantly higher spikelet, ear and plot yields. If these results are repeatable in other varietal backgrounds, over seasons, and under differing environmental conditions, Rht1 (B. dw) should have considerable commercial potential as an alternative allele for producing shorter‐than‐average, high‐yielding, semi‐dwarf wheat varieties.
Resistance to viruses in F1hybrids produced by direct crossing between diploidSolanumseriesTuberosaand diploidS. brevidens(seriesEtuberosa) usingS. phurejafor rescue pollination
Authors: Valkonen J. P. T. , Orrillo M. , Slack S. A. , Plaisted R. L. , Watanabe K. N.
Published: April 2006

Resistance to potato viruses was examined in the F1hybrids (TET) obtained from a cross between a diploid (2n = 24), tuber‐bearing interspecific hybrid 87HW13.7 (Solanum tuberosumW231 ×S. multi‐dissectumPI 473354) and a diploid (2n = 24), nontuber‐bearing wild potato species (S. brevidensCPC 2451) usingS. phurejaIvP35 (2n = 24) for rescue pollination. The parental plants were susceptible to PVX, whereas two hybrids (TET38.2 and TET38.9) andS. phurejaIvP35 reacted with hypersensitivity to PVX. Two hybrids (TET 38.9 and TET 38.12) were extremely resistant to PVY°, which was similar toS. brevidensandS. phurejaIvP35, whereas the remaining two hybrids were moderately resistant to PVY°. No resistance to PVA and PLRV was observed in the progenies, in contrast toS. brevidenswhich was extremely resistant to PVA and PLRV. Hypersensitivity to PVX in two progenies suggested (1) integration by somatic translocation or heterofertilization and expression of genes from the rescue pollinatorS. phurejaIvP35, or (2) transgressive or complementary gene action.
Molecular markers and protein quantities as genetic descriptors in maize. II. Prediction of performance of hybrids for forage traits
Authors: Burstin J. , Charcosset A. , Barriére Y. , Hébert Y. , de Vienne D. , Damerval C.
Published: April 2006

As it is related to the variability in genome expression, variability in protein quantities revealed by two‐dimensional electrophoresis was proposed for describing phenotypic diversity. The objective of this study was to compare the predictive power of different genetic distances derived from molecular markers and from protein quantitative variations in a diallel of 210 hybrids among 21 maize inbred lines (Zea mays L.) of various origin. The lines were characterized for: 1. 142 markers resulting from the analysis of enzyme, RFLP, and protein‐structure polymorphism; and 2. The variation in relative quantities of 190 proteins. The hybrids were evaluated for six forage traits in four environments. Correlations between the genetic distances computed for 142 marker loci and hybrid performances were moderate to high in diallels using crosses between related lines. Genetic distances based on protein quantities showed, in most cases, similar or lower correlations. Distance measures were not useful as predictors of hybrid performance for crosses between unrelated lines. Protein quantities were better for revealing specific genotypes.
A stable cytoplasmic male‐sterile line of Brassica juncea carrying restructured organelle genomes from the somatic hybrid Trachystoma ballii+B. juncea
Authors: Kirti P. B. , Mohapatra T. , Baldev A. , Prakash S. , Chopra V. L.
Published: April 2006

A cytoplasmic male‐sterile (CMS) line of Brassica juncea has been developed by combining the cytoplasm originating from the somatic hybrid Trachystoma ballii+B. juncea, and the nucleus of B. juncea cv. Pusa Bold by repeated backcrossing. Male‐sterile plants closely resembled the normal fertile B. juncea in general morphology, but had delayed flowering (5–7 days) when compared with fertile ‘Pusa Bold’ which flowered in 45 days. Stamens of the male‐sterile line were transformed into petaloid structures. Pollen abortion occurred after tetrad formation. Female fertility of the male‐sterile line was normal. Molecular analysis of organelle genomes indicated extensive mitochondrial DNA recombinations in the CMS line. Preliminary analysis of the chloroplast genome of the CMS line also indicated chloroplast DNA recombination.
Karyotype and C‐banding pattern of mitotic chromosomes in alfalfa, Medicago sativa L.
Authors: Falistocco E. , Falcinelli M. , Veronesi F.
Published: April 2006

Numerous cytogenetic studies have been performed on alfalfa (Medicago sativa L. 2n= 4x= 32), but only a few have examined the somatic chromosomes. Because the major factor limiting the study of somatic chromosomes of M. sativa is their rather uniform morphology, characterization was attempted using the C‐banding technique instead of the traditional Feulgen method. Chromosome morphology and position of the heterochromatic bands resulted in satisfactory characterization of the chromosomes and provided further evidence of the autotetraploid origin of the species. It was possible to identify the homologous chromosomes and arrange them into eight groups of four. The ideogram of the basic genome of eight chromosomes was constructed. The impact of these results on cytogenetic studies and breeding research in alfalfa is discussed.
Genetic analysis and nomenclature for seven isozyme systems in Brassica nigra, B. oleracea and B. campestris
Authors: Chevre A. M. , Delourme R. , Eber F. , Margale E. , Quiros C. F. , Arus P.
Published: April 2006

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.
The 1BL/1RS chromosome translocation effect on yield characteristics in a Triticum aestivum L. cross
Authors: Villareal R. L. , del Toro E. , Mujeeb‐Kazi A. , Rajaram S.
Published: April 2006

Comparisons involving 28 random F2‐derived F6 wheat (Triticum aestivum L.) lines from the cross, ‘Nacozari’/‘Seri 82’, suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives. This performance advantage was attributed to high grain yield, above‐ground biomass at maturity, grains/spike, 1000‐grain weight and test weight. The 1BL/1RS lines were shorter with delayed flowering and maturity. The superiority of the 1BL/1RS translocation group on grains/m2 was expressed only under the full irrigation environment. Higher harvest index, longer spike‐length and grain‐filling period were detected only under reduced irrigation conditions. A significant grain yield relationship with test weight was detected only among the 1BL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1B genotypes.
Genetic variability in antibiotic resistance to the greenbug Schizaphis graminum in Hordeum chilense
Authors: Castro A. M. , Martían L. M. , Dixon A. F. G.
Published: April 2006

Hordeum chilense (Roem. et Schult), a native grass of South America, is a source of antixenotic and antibiotic resistance to the greenbug Schizaphis graminum Rondani. The genetic and environmental components of the variability in antibiotic resistance shown by H. chilense were determined by measuring the developmental time, the length of adult life, fecundity and intrinsic rate of population increase of green‐bugs reared on this host. The aphids belonged to a clone of biotype C. Plants were cloned to reduce the incidence of environmental variability.

Different plant characters appeared to prolong aphid developmental time and reduce the length of adult life and total fecundity. The broad sense heritability and the genetic variability of these plant characters were different. The plant character that affected aphid development appears to differ from that affecting fecundity.
Optimization of DNA amplification fingerprinting techniques to study genetic relationships of white lupin germplasm
Authors: Qiu J. , van Santen E. , Tuzun S.
Published: April 2006

DNA amplification fingerprinting (DAF) techniques were used to evaluate genetic relationships among 24 randomly selected white lupin (Lupinus albus L.) accessions originating from four endemic regions. Parameters affecting DAF were optimized to obtain high resolution and reproducible banding patterns. DNA amplification was tolerant to a wide range of both template and primer concentrations but sensitive to Mg2+ concentration, and annealing temperature and time. Pure template DNA was found to be essential for obtaining reproducible banding patterns. Primer annealing occurred at multiple sites, permitting detection of polymorphism using only a single primer. Of 56 octamer primers tested, 22 yielded highly polymorphic DAF bands that could be used to distinguish closely related accessions. Genetic similarity coefficients were calculated and a dendrogram, using the unweighted pair group method with arithmetic average (UPGMA), was constructed. A high level of genome diversity was found among the accessions, but several from the Middle East and West Africa tended to cluster together. The results support the future use of DAF markers for the characterization and identification of white lupin germplasm.
The incompatibility system in Italian red chicory (Cichorium intybus L.)
Authors: Varotto S. , Pizzoli L. , Lucchin M. , Parrini P.
Published: April 2006

As a result of an incompatibility mechanism which prevents both self‐fertilization and intermating between plants with identical genotypes, inbreeding does not occur in Cichorium intybus. This self‐incompatibility system complicates the production of inbred lines and the generation of F1 hybrids in Italian red chicory.

Histological observations on pollinated stigmas show that the incompatibility reaction in chicory is very rapid and either prevents pollen adhering to the stigmatic papillae or determines the arrest of pollen‐tube growth on the stigmatic surface; incompatible pollen cannot reach the transmitting tissue of the style.

Both histological and genetic analyses of F1 progeny from a reciprocal cross between two unrelated plants suggest the occurrence of a sporophytic incompatibility system in Italian red chicory.
Lack of durability of resistance to cereal rusts in wheat when selection is for complete resistance
Authors: Danial D. L. , Kirigwi F. M. , Parlevliet J. E.
Published: April 2006

Twenty‐one bread‐wheat entries were selected after careful screening for complete or near‐complete resistance to yellow rust (Puccinia striiformis), stem rust (P. graminis), and leaf rust (P. recondita). In 1987, the 21 entries were intercrossed in a near‐half diallel scheme. The resulting 190 F2 populations were advanced to F7 under selection for complete resistance to the three rusts and for good agronomic types. In 1992 the 21 parents and 140 selected F7 lines were assessed for their resistance to the three rusts. Of the 21 parents, 12 showed a breakdown of yellow rust resistance, five a breakdown of stem rust resistance and two a breakdown of leaf rust resistance. In addition, several of the 140 selected F7 lines, all still resistant in F6, had become susceptible to one or more of the rusts. It appears that a progression towards more complex races, especially of yellow rust, is inevitable for the wheat‐cereal rust patho‐systems when the selection is for complete or near‐complete resistance.
Substitution analysis of drought tolerance in wheat (Triticum aestivumL.)
Authors: Farshadfar E. , Köszegi B. , Tischner T. , Sutka J.
Published: April 2006

Chromosome substitution lines of the wheat variety ‘Cappelle Desprez’ into ‘Chinese Spring’ were tested for drought tolerance in growth chambers in the Martonvásár phytotron. Three different moisture regimes were created: E1, fully irrigated control; E2, mid‐season water stress (preanthesis); and E3, terminal water‐stress during grain filling. Data were analysed to estimate the chromosomal location of the genes controlling relative water‐content (RWC), relative water‐loss (RWL), drought‐susceptibility index (DSI) and phenotypic stability in each substitution line. Simultaneous consideration indicated that most of the genes controlling these characters are located on chromosomes 1A, 5A, 7A,4B, 5B, 1D, 3D and 5D.
Breeding a genie and cytoplasmic double‐MS line of rapeseed (Brassica napus L.)
Authors: Li J. , Tang Z. , Zhang X. , Shen L.
Published: April 2006

All rapeseed lines with Polima male sterility (MS) that are applied in hybrid cultivars have the problem that their sterility varies with temperature. To overcome this problem, two double‐MS lines with genie (GMS) as well as cytoplasmic male sterility (CMS) genes were synthesized through seven generations of breeding, based on a systematic study of changes in fertility of the genie and cytoplasmic male sterility lines. The fertility of the new sterility lines was determined by observation of the floral organs and by pollen staining. The results showed that, in the double‐MS lines, half the plants maintained the features of the Polima CMS line, while the other half behaved like the GMS line. The GMS genes were correctly expressed in the Pol cytoplasm, but there was little interaction between the GMS and CMS genetic systems.
Attempts to overcome postfertilization barrier in interspecific crosses of the genus Lens
Authors: Ahmad M. , Fautrier A. G. , McNeil D. L. , Burritt D. J. , Hill G. D.
Published: April 2006

Wild relatives are a potential source of genetic diversity to lentil (Lens culinaris Medik). The objective of this research was to obtain viable interspecific hybrids between the domesticated lentil and its wild relatives.

The paper details the results of a number of interspecific crosses among L. culinaris, L. orientalis, L. odemensis, L. ervoides and L. nigricans. Viable hybrids were produced between L. culinaris × L. orientalis, L. culinaris × L. nigricans, L. culinaris × L. ervoides and between L. culinaris × L. odemensis. Further viable hybrids were obtained between L. culinaris and L. ervoides, which have the potential to be a ‘bridge’ in hybridization to L. culinaris for specific L. nicrigans lines which proved recalcitrant in L. culinaris × L. nigricans crosses. This is the first time that four wild species of lentils have been used successfully in hybridization with cultivated lentils, and viable hybrids produced. This paper also suggests that the artificial supplement of GA3, hormone is needed after fertilization for the normal growth of the hybrid embryo, possibly as the natural GA3 production is restricted with alien pollinations in cultivated lentils in both F1 and backcross hybrids.
Identification of specific powdery‐mildew‐resistance genes in individual wheat plants using the first two seedling leaves
Authors: Le Boulc'h V. , Goyeau H. , Brabant P. , de Vallavieille‐Pope C.
Published: April 2006

Identification of resistance genes in individual plants requires the use of leaves that have homogeneous reactions to the pathogen. The reactions of the first two leaves of seedlings of 12 wheat differential varieties to 20 Erysiphe graminis f.sp. tritici isolates were compared using in vitro tests on detached leaf segments. The expression of resistance and susceptibility did not differ significantly between the first two leaves with the 12 resistance genes tested. Consequently, the identification of specific powdery‐mildew‐resistance genes in individual plants is possible if approximately 10 segments of the primary and secondary leaves are used, each of them inoculated by one out of a set of 10 differential isolates. The reaction pattern of a plant to the tester isolates is interpreted according to a procedure in two steps, that are easily computerized. Identification of resistance genes in individual plants is particularly useful for resistance studies in heterogeneous plant populations.
Aluminium tolerance in wheat: correlating hydroponic evaluations with field and soil performances*
Authors: Baier A. C. , Somers D. J. , Gusiafson J. P.
Published: April 2006

The objective of this study was to correlate root length of wheat (Triticum aestivum L.) genotypes grown in Al‐containing, acidic hydroponic solutions, with root weights from acid‐soil experiments and field scores from Brazilian acid‐field trials. A total of 43 wheat genotypes, primarily from Brazil, were evaluated by growing seedlings for 4 days in hydroponic solutions containing 0.0–4.0 mg/l Al. The root growth rate of all the genotypes was reduced with the addition of Al to the solution and the Al‐sensitive and Al‐tolerant wheat genotypes were clearly identified. Genotypes with intermediate Al‐tolerance levels showed variable root lengths in response to Al stress. Correlations between root length or a root tolerance index (RTI) in the Al solutions versus acid‐soil experiments and acid‐field trials were highly significant (r = 0.71–0.85, P < 0.01). The most significant correlation was observed among seedlings grown in 1 mg/1 Al. This study presents evidence that this short duration and simple screening technique provides a highly significant correlation with previous acid‐soil Al‐tolerance evaluations. Furthermore, the data obtained suggest that hydroponic screening of wheat seedlings for Al tolerance may be used in breeding programmes or in screening germplasm collections.