bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations among Fusarium culmorum head blight resistance, fungal colonization and mycotoxin contents in winter rye
Authors: Mledaner T. , Perkowski J.
Published: April 2006

Fusarium culmorum head blight infections may lead to accumulation of toxic metabolites in winter rye grain. To estimate the correlation between resistance traits, fungal colonization and accumulation of deoxynivalenol (DON), 3‐acetyldeoxynivalenol (3‐AcDON) and zea‐ralenone (ZEA), 27 winter rye single‐cross hybrids were artificially inoculated in 1992 and 1993. Resistance traits were head blight rating and grain weight of the inoculated relative to the non‐inoculated plots. Fungal colonization was determined by the analysis of ergosterol (ERG) content in the grain. Head blight rating and relative grain yield showed a medium to high disease severity and ERG indicated a considerable fungal colonization of the kernels with a mean of 85 mg/kg in 1992 and 66 mg/kg in 1993. DON content among genotypes ranged from 0.7–28 mg/kg in 1992 and from 11 to 35 mg/kg in 1993. 3‐AcDON and ZEA contents were low in both years with overall means of 1.1 and 0.09 mg/kg, respectively. Across both years, considerable genotypic variation was found for head blight rating, relative grain weight, and ERG content with medium to high heritabilities (0.6–0.7). For the mycotoxin contents, however, genotype‐year interaction variance was the most important source of variation. The correlations between relative grain weight and DON, 3‐AcDON, or ZEA were low in 1992 (r ∼ 0.3), but considerably higher in 1993 (r ∼ 0.7, P = 0.01). In contrast, correlation between relative grain weight and ERG was significant in both years (r ∼ 0.5, P = 0.01). In F. culmorum head blight infections, DON, 3‐AcDON and ZEA contents appear to be affected, at least partially, by different environmental factors than resistance traits and fungal colonization.
Cytometric and morphometric identification of diploid, tetraploid and pentaploid plants derived from Actinidia arguta (2n = 4x) crossed with A. deliciosa (2n = 6x)
Authors: Chat J. , Dumoulin P. Y. , Bastard Y. , Monet R.
Published: April 2006

Interspecific crosses between Actinidia arguta (In = 4x) and A. deliciosa (2n = 6x) were carried out in order to transfer cold resistance from a wild to the cultivated kiwifruit species. Of the 65 progenies obtained and analysed by flow cytometry, 16 were diploid, one was tetraploid and 48 were, as expected, pentaploid. Morphologically, the diploids can be distinguished from the pentaploids by their longer lamina. The existence of 5x progenies confirms the existence of gene flow between A. arguta and A. deliciosa, whereas the existence of 2x and 4x progenies provides evidence for parthenogenesis within the Actinidia genus following an interspecific cross. The study demonstrates the utility of flow cytometry for genomic analysis of progenies derived from interspecific crosses. Possible uses of both sexual and parthenogenetic progenies in the breeding and genetics of kiwifruit are discussed.
Production of intergeneric hybrids between Raphanm and Moricandia
Authors: Bang S. W. , Kaneko Y. , Matsuzawa Y.
Published: April 2006

Intergeneric F1 hybrids between Raphanus sativus (2n = 18, RR) and Moricandia arvensis (2n = 28, MaMa) have been produced through ovary culture followed by embryo culture, when M. arvensis was used as a pistillate parent. Six BC1 plants were also obtained through ovary culture followed by embryo culture in the backcross of an amphidiploid F1, hybrid with R. sativus cv. ‘Pink ball’. Two BC1 plants were ses‐quidiploids (2n = 32, MaRR), and the other BC1, plants were hyperploid with 2n = 55, having MaMaRRR genomes. BC2, seeds were obtained by conventional pollination in the successive backcross of two sesquidiploid BC1, plants with R. sativus cv.‘Pink ball’. Their seed set percentages were 12.7% and 17.0%, respectively. These novel hybrid plants and derived progenies may be valuable materials for the genetic investigation and breeding of Brassiceae, including R. sativus.
Establishment of a random‐mating population of ‘Polima’ CMS restorers in Brassica napus by use of dominant genie male sterility
Authors: Yang G. S. , Fu T. D. , Ma C. Z. , Yang X. N.
Published: April 2006

Five restorers of ‘polima’ cytoplasmic male sterility (pol CMS) cannot restore the fertility in dominant genie male sterility (DGMS). A dominant male sterility gene from both, a DGMS line Rs l046AB and DGMS hybrid ‘Zhongza No. 3’, was successfully introduced into Polima cytoplasm. A random‐mating population of pol CMS restorers was established by using many double‐low pol CMS restorers as pollinators to cross continuously to the DGMS plants which had Polima cytoplasm.
Resynthesis of rapeseed (Brassica napus L.): A comparison of sexual versus somatic hybridization
Authors: Heath D. W. , Earle E. D.
Published: April 2006

Sexual and somatic Brassica napus hybrids produced from the same parental plants were compared. Sexual crosses between a white‐flowered, self‐compatible broccoli selection (B. oleracea var. italica, cc genome) as the maternal parent and a flowering pak choi accession (B. chinensis, aa genome) yielded one unique spontaneous hybrid and four hybrids through embryo rescue. Thirty‐nine somatic hybrids were recovered from a protoplast fusion experiment. Hybridity was confirmed by morphology, isozyme expression, flow cytometry, and DNA hybridization. Sexual and somatic hybrids exhibited differences in leaf morphology, flower colour, flowering habit, and organellar inheritance. Sexual hybrids were all fertile amphidiploids (2n = 38, aacc) following spontaneous chromosome doubling. All somatic hybrids had high nuclear DNA contents; most were probably hexaploids (aaaacc or aacccc) from the fusion of three portoplasts. Two initially sterile hexaploid (aaaacc) regenerates eventually set selfed seed after the loss of the putative extra aa genome following regrowth from axillary buds. A bias toward inheritance of B. chinensis chloroplasts was observed with somatic hybrids.
Cultivar × rhizobial strain interactions in peas with respect to early symbiosis, nodule initiation and N uptake
Authors: Mårtensson A. M. , Rydberg I.
Published: April 2006

Sixteen pea cultivars differing in their phenotypic characteristics were studied in order to characterize the cultivars' variability in symbiotic characters using three Rhizobium leguminosarum biovar viceae strains. The peas did not show any cultivar × strain interactions with the rhizobial strains used with respect to root hair infection frequency or day of nodule initiation. Three cultivars had high root hair infection frequencies, and five had only a few infected root hairs. Four of five leafless/semi‐leafless varieties investigated and one cultivar with normal leaves formed nodules quickly, whereas three varieties with normal leaves formed nodules slowly. Ten of the cultivars showed cultivar × strain interactions with respect to N uptake, indicating that the performance of the N2‐fixing symbioses depends on the rhizobial partner. Six cultivars showed cultivar × strain interactions with respect to dry matter production and the nodule proportion of the dry matter. Of the cultivars investigated, we conclude that some of the leafless/semi‐leafless varieties (‘Capella’, ‘Filby’ and ‘Solara’) are suitable for inclusion in a future breeding programme, since these cultivars combined several important symbiotic characters.
PCR‐based assay for detecting IB‐genes for low molecular weight glutenin subunits related to gluten quality properties in durum wheat
Authors: D'Ovidio R. , Porceddu E.
Published: April 2006

A PCR assay has been developed for selecting low molecular weight (LMW) glutenin genes, located on chromosome 1B, and related to durum wheat quality characteristics. Most durum wheat lines possessing good technological properties can be identified on the basis of the presence of specific 1B LMW glutenin components that have been designated LMW‐2 glutenin subunits. On the basis of nucleotide sequences corresponding to LMW glutenin genes, a series of specific oligonucleotide primers were prepared and used in PCR analysis. A pair of these primers gave a single amplification product which can distinguish between durum wheat lines possessing LMW‐2 glutenin subunits and lines possessing other 1B‐LMW allelic variants. Because the proposed PCR analysis can be carried out using part of the endosperm of a single seed, it represents a helpful approach for speeding up the selection of genotypes possessing LMW‐2 glutenin subunits. This part of primers could also be very useful in genome mapping analysis and for testing the purity of wheat flour stock.
Short Communication Comparison between QTL analysis of powdery mildew resistance in barley based on detached primary leaves and on field data
Authors: Backes G. , Schwarz G. , Wenzel G. , Jahoor A.
Published: April 2006

A quantitative trait loci (QTL) analysis of quantitative powdery mildew resistance was performed on 216 doubled haploid lines derived from a cross between the winter‐barley varieties ‘Igri’ and ‘Danilo’ using 67 RFLP loci. Resistance to powdery mildew was determined in the field with natural infection and on detached primary leaves with a specific isolate. The major QTL found in both sets of analysis mapped to the same chromosomal region. No further QTL could be found in the analysis based on detached leaves and one additional minor QTL was found in the analysis based on field data.
Short Communication A low morphine‐containing accession of Papaver somniferum suitable for seed production*
Authors: Bajpai S. , Gupta M. M. , Kumaru S.
Published: April 2006

A total of 140 Indian accessions of Papaver somniferum were raised under the subtropical conditions of Lucknow, India. They were screened for major alkaloids present in the capsules and peduncles, using a TLC‐densitometry procedure. An accession containing the narcotic alkaloid morphine at as low a concentration as 0.05% in its capsules has been identified. The accession has good agronomic traits.
Pod volume and pod‐filling percentage as additional traits for the characterization of chickpea (Cicer arietinum L.)
Authors: Pundir R. P. S. , Reddy G. V.
Published: April 2006

Thirty short‐ to medium‐duration chickpea germplasm accessions from diverse geographic origins and with a wide range of physiological and morphological traits were grown in three environments at ICRISAT Asia Center, Patancheru, during 1992/93. Data were recorded on time to flowering, leaf area, 100‐seed mass, pod volume, and pod‐filling percentage. Quantitative data on the last two traits were recorded for the first time to examine their relevance to the characterization of germplasm accessions and their use as selection criteria in breeding. The accessions exhibited considerable variation for the traits. The broad‐sense heritabilities were 0.98 for pod volume and 0.85 for pod‐filling percentage. The two traits showed consistent relationships with other morphological characters indicating that the pod volume and pod‐filling percentage traits can be utilized in genotype characterization of chickpea.
Rapid screening of selected European winter wheat varieties and segregating populations for the Glu‐D1d allele using PCR
Authors: Varghese J. P. , Struss D. , Kazman M. E.
Published: April 2006

Forty‐two winter wheat varieties and 193 F2 and BC1F2 seeds were screened for Glu‐D1d allele encoding the HMW glutenin subunits 5 + 10 using polymerase chain reaction (PCR). The segregating populations originated from crosses involving wheat parents with good and poor bread‐making quality. A clear PCR product of 450 bp, representing 1Dx5 of the Glu‐D1d allele was identified in 24 varieties and 111 hybrid seeds. Four different Glu‐D1 alleles: a (2 + 12), b (3 + 12), c (4 + 12) and d (5 + 10) were detected using sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE). Only genotypes possessing Glu‐D1d gave a positive PCR signal, hexaploid triticale and 4 × wheat lacking Glu‐D1 locus gave a negative signal. The efficiency of PCR selection for bread‐making quality in early generations using half seed is discussed.
Genetic response to index selection for grain yield, kernel weight and per cent protein in four wheat crosses
Authors: Gebre‐Mariam H. , Larter E. N.
Published: April 2006

Quantitative genetic theory was used to investigate selection differentials, expected and observed direct and correlated responses to simultaneous improvement of grain yield, kernel weight, and grain protein content in F3 and F4 populations of four spring wheat (Triticum aestivum L.) crosses. Selection in the F3 generation based on the Smith‐Hazel index (SH) and yield was found to be superior to the other methods studied in identifying high‐yielding lines, but resulted in substantial decrease in grain protein level. Consequently, a 1.0% increase in protein from selection for protein depressed grain yield as much as 536 kg/ha below the population mean, reducing the expected yield gains per generation selection cycle by 250%. The weight‐free indices (EW), particularly the index involving only yield and kernel weight (EW3) and its linear approximation (EW4), and the desired gains indices were effective in improving protein content but were less efficient in selecting top‐yielding lines. Selection in the opposite direction using truncation of the lowest 10% of the population based on weight‐free‐index involving yield, kernel weight and protein (EW2) reduced all traits significantly compared with the mean of the unselected population indicating the effectiveness of the unweighted selection index. The observed genetic gains (Ra) from selection based on yield, the SH, EW3 and EW4 indices were slightly lower than the expected advances per cycle (R) in populations from crosses ‘Sinton’×‘Glenlea’ (C1), ‘Glenlea’×‘NB505’ (C2), and ‘A2P5’×‘NB320’ (C6) (Ra/R = 70 to 85%) but were higher in cross ‘NB505’×‘A2P5’ (C5) (Ra/R = 126 to 143%). It was concluded that weight‐free and the desired gains indices can be used to improve wheat grain yield and grain protein simultaneously in F3 generation selection, as revealed by response to selection measured in the F4 generation.
Breeding perennial ryegrass with better crown rust resistance
Authors: Reheul D. , Ghesquiere A.
Published: April 2006

Improving rust resistance is one of the main goals in our breeding programme with perennial ryegrasses. We have studied the behaviour of our breeding material over several years in several locations under natural and artificial infection conditions. The narrow sense heritability of crown rust resistance is fairly high (0.46), providing scope for improving resistance, but this optimism is reduced by the negative correlation with yield. The most resistant material yielded 4% less than the most susceptible material. No decline in digestibility is expected when improving the disease resistance. The incidence of crown rust is very variable between years, locations and between spontaneous and artificial infections, creating constraints in selection.

Observations for several years and at several locations appear to be the best way to improve rust resistance in perennial ryegrass.
Use of isozyme analysis in the breeding of synthetic rapeseed cultivars
Authors: Hackenberg E. M. , Köhler W.
Published: April 2006

Eleven winter rapeseed inbred lines (I4) were characterized according to isozyme banding patterns from seven polymorphic enzyme systems. All lines could be qualitatively and quantitatively distinguished using two enzyme systems, shikimate dehydrogenase (SDH) and diaphorase (DIA). Genetic distances were calculated among lines and 15 selected two‐line hybrids were planted as experimental synthetics in field‐trials. Syn‐0 populations produced seed yields between 0.4% lower and 12.9% higher than the mean yields of the respective parental lines. Syn‐1 seed yields were 11–24.1% higher than the respective parental lines and the yield improvement was positively correlated with the genetic distance between the parental lines. This tendency suggests that genetic distances between cross components, calculated from isozyme polymorphism, can be used in prognosis of yield performance of synthetic rapeseed cultivars. Isozyme analysis was also applied to study fertilization behaviour in line mixtures, and differences among parental lines were observed with regard to the tendency for self‐pollination or out‐crossing. The partially very high outcrossing rate suggests the possible existence of a self‐incompatibility system.
Cytogenetical and molecular investigations on somatic hybrids of Sinapis alba and Brassica juncea and their backcross progeny
Authors: Gaikwad K. , Kirti P. B. , Sharma A. , Prakash S. , Chopra V. L.
Published: April 2006

Somatic hybrids of Sinapis alba+Brassica juncea (Sal Sal AABB) were synthesized by protoplast electrofusion. They were true genomic allopolyploids since they possessed 60 chromosomes, i.e. the sum of S. alba (2n= 24) and B. juncea (2n= 36) chromosomes. Chromosome pairing was predominantly bivalent with the occasional occurrence of multivalents in the pollen mother cells at diakinesis and metaphase I. Hybrids were completely pollen‐sterile, but produced seeds on back‐crossing with B. juncea and B. campestris. A total of 37 BC1 plants were raised from two somatic hybrids (JS‐1 and JS‐2) and 24 of these were analysed cytologically. The 22 plants originating from the pollinations of somatic hybrids with B. juncea showed a chromosome configuration of 18II+12I and had 42–86% pollen fertility. Two plants from the backcrosses of the somatic hybrid with B. campestris formed 10II +20I, and had 0–4% fertile pollen. Total DNA analysis by probing with pTA71 carrying a full‐length 18S–25S rDNA fragment of the wheat nuclear genome revealed that the two somatic hybrids possessed all the characteristic bands of both the species, confirming their hybridity. Probing with the mitochondrial coxI and atp9 genes indicated mitochondrial genome recombination in the hybrids. Hybridization with chloroplast‐specific psbD indicated that both the somatic hybrids possessed the cp genome of S. alba origin.
Influence of the apetalous character in rape (Brassica napus) on the foraging behaviour of honeybees (Apis mellifera)
Authors: Pierre J. , Pierre J. S. , Marilleau R. , Pham‐Delègue M. H. , Tanguy X. , Renard M.
Published: April 2006

In order to establish whether commercial hybrid seed production between apetalous and apetalous rapeseed lines could be developed through insect cross‐pollination, observations were made to compare the foraging behaviour of honeybees on both flower types with regard to their attractiveness. Number of flowers/m2 and nectar volumes, considered as important attractive factors, did not differ between the two lines but nectar sugar composition was slightly different. Honeybee density was significantly higher on the apetalous line when their foraging activity was rather high. Honeybees showed a considerable constancy to each flower type. Passages between both types were not very frequent. Nectar foraging behaviour, observed under cages, differed with the floral morphology. On the apetalous flowers, honeybees visited the two inner nectaries by crawling over the anthers and the stigma, while on the apetalous ones they often inserted their tongues between the sepals, thus having less contact with the reproductive organs. From these results, the honeybee efficiency in cross‐pollination between petalous and apetalous lines appears to be reduced.
Screening for scab resistance by RAPD markers in cultivars of apple (Malus spp.)
Authors: Marn M. Viršček , ŠTampar F. , Javornik B.
Published: April 2006

Genetic markers are a much faster and more practical alternative to classical methods for the identification of genes for scab resistance present in different apple cultivars. In our study, 28 scab‐resistant cultivars, four wild sources of the resistance genes and 10 susceptible cultivars were screened for the presence of the RAPD fragments OPM18/900, OPD20/600 and OPA15/900, which are reported to be linked to the Vf gene. All three marker fragments were successfully amplified with different protocols in Vf‐resistant cultivars including ‘M. floribunda 821’. No marker fragments were amplified in susceptible cultivars, three out of four Va‐resistant cultivars, three out of four Vm‐resistant cultivars, two Vr‐resistant cultivars, ‘Antonovka PI 172612’ and ‘M. pumila R 12740‐7A’. All three markers were found in the cv. ‘Nova Easygro’, reported to possess the Vr gene, and the cv. ‘Reglindis’, reported to be Va‐resistant. M. atrosanguinea of unknown origin showed the presence of OPD20/600 and OPA 15/900 marker bands. The cvs. ‘Nova Easygro’, ‘Reglindis’ and M. atrosanguinea are probably carriers of the VF gene.
Stability of male‐sterile sources and fertility restoration of their hybrids in pearl millet
Authors: Rai K. N. , Virk D. S. , Harinarayana G. , Rao A. S.
Published: April 2006

Genetic background has a significant effect on the expression of cytoplasmic‐nuclear male sterility (CMS) in pearl millet (Pennisetum glaucum (L.) R. Br.). Therefore, a reliable characterization of CMS sources requires the use of near‐isonuclear lines and their hybrids. We used this approach to characterize five CMS sources (A1, A2, A3, Av, and A4). Male sterility of 81A4 was the most stable, followed by 81A1 and 81Av, indicating the relative merits of these CMS sources in breeding stable male‐sterile lines. Male‐sterile lines 81A2 and 81A3 were highly unstable, indicating their minimal value. Differential male fertility restoration patterns of hybrids made on 81AV and 81A4 suggest that the Av and A4 cytoplasms represent CMS systems that are different from each other and from A1, A2 and A3. An evaluation of topcross hybrids of 15 diverse populations made on 81A1 and 81A4 showed that each population had restorers and maintainers of both cytoplasms and that the frequency of maintainers of A4 was as high as, or higher than, that of the A1 cytoplasm. Thus, use of the A4 cytoplasm can substantially increase the probability of breeding stable male‐sterile lines based on inbreds developed from diverse genetic backgrounds, and also provide the opportunity for breeding restorers from each of these diverse genetic sources.
Locating supplementary RFLP markers on barley chromosome 7 and synteny with homoeologous wheat group 5
Authors: RouvèS S. , Boeuf C. , Zwickert‐Menteur S. , Gautier M. F. , Joudrier P. , Bernard M. , Jestin L.
Published: April 2006

In order to develop QTL applications, eight new loci were mapped on barley chromosome 7 using 124 doubled haploid lines of the North American Barley Genome Mapping Project (NABGMP) progeny (‘Steptoe’×‘Morex’)‐ These loci involve six genomic DNA restriction fragment length polymorphisms (RFLPs) and two cDNA‐RFLPs including a puroindoline gene. The distribution of these markers on barley chromosome 7 was compared with that of homoeologous wheat counterparts, i.e. wheat group 5. One locus on chromosome 7 was associated with a QTL for β‐glucanase activity measured in green and finished barley malt.
Consequences of classical and biotechnological resistance breeding for food toxicology and allergenicity
Authors: Franck‐Oberaspach S. L. , Keller B.
Published: April 2006

The first food products derived from transgenic plants that are resistant to diseases, insects or viruses are now reaching the market and there is growing public concern about problems of allergenicity and toxicological changes in such transgenic food plants. We review the modifications being carried out or envisaged in molecular resistance breeding and specifically consider the allergenic and toxicological potential of the gene products used. Several protein families that contribute to the defence mechanisms of food plants have members which are allergens or putative allergens and some of these proteins are used in molecular approaches to increase resistance. These include α‐amylase and trypsin inhibitors, lectins and pathogenesis‐related proteins. An assessment procedure to avoid the transfer of such allergens is described. The source of the transgene is of great importance for the application of immunological assays. In addition to putative changes in the allergenic potential, the toxicological implications of classical and molecular resistance breeding are discussed. Several ‘self defence’ substances made by plants are highly toxic for mammals, including humans. Examples of molecular approaches that could be of toxicological concern are given. The source of the transgene is of no relevance in assessing the toxicological aspects of foods from transgenic plants. Food safety can also be severely influenced by invading pathogens and their metabolic products. This may result in a trade‐off situation between ‘nature's pesticides’ produced by transgenic plants or varieties from traditional breeding programmes, synthetic pesticides and mycotoxins or other poisonous products of pests.
Glucosinolate content in interspecific crosses of Brassica carinata with B. juncea and B. napus
Authors: Getinet A. , Rakow G. , Raney J. P. , Downey R. K.
Published: April 2006

Brassica carinata A. Braun is a highly productive oilseed crop in the Ethiopian highlands, but the seed has a high 2‐propenyl glucosinolate content, which is undesirable. The objective of this study was to introgress, through interspecific crosses, genes for low 2‐propenyl glucosinolate content from the B genome of B. juncea and C genome of B. napus into the B. carinata B and C genomes and thus develop low glucosinolate B. carinata. The cross [(B. carinata×B. juncea) ×B. carinata] yielded plants that contained only ∼ 20 μmoles of 2‐propenyl glucosinolate, which was an 85% reduction compared with levels in B. carinata seed. Plants of the [(B. carinata×B. napus) ×B. carinata] cross had normal high concentrations of 2‐propenyl glucosinolate. Backcross plants of both interspecific crosses also contained 3‐butenyl and 2‐hydroxy‐3‐butenyl glucosinolates. The results of these crosses suggested that genes for glucosinolate synthesis were located on B genome chromosomes of B. carinata because B. napus C genome introgressions did not result in reductions of total glucosinolate contents. The total alkenyl glucosinolate content of one F3 family of the B. juncea backcross was similar to that of the B. juncea parent. It was concluded that through further selection in this family, B. carinata plants could be identified that would be basically free of 2‐propenyl glucosinolate, and have a low total alkenyl glucosinolate content.
The control of adult‐plant resistance to yellow rust by the translocated chromosome 5BS‐7BS of bread wheat
Authors: Law C. N. , Worland A. J.
Published: April 2006

The reciprocal translocation 5BL‐7BL and 5BS‐7BS was widespread in West European wheats 30 years ago, and is probably present in many of their descendants today. In varieties with a history of durable adult‐plant resistance to yellow rust and carrying this translocation, removal of the 5BS‐7BS chromosome gave adult plants which were much more susceptible. It was suggested that this chromosome might therefore carry the gene(s) responsible for a major part of their resistance and possibly their durability. To test this, a series of lines was developed in which 5BS‐7BS chromosomes from both resistant and susceptible varieties were substituted into a number of the durably resistant varieties. In every case, the substituted 5BS‐7BS chromosome, irrespective of origin, was found to produce the resistant phenotype, indicating that background chromosomes were responsible for the differences between the varieties. The resistance and durability of the resistant varieties cannot therefore be due solely to the translocated chromosome. In similar experiments, the 5BS and 7BS arms from varieties not carrying the translocation were substituted into a variety carrying the translocation. In each instance, the lines with the substituted arms were much more susceptible than their recipient, confirming the major effect of the 5BS‐7BS chromosome on resistance. The complete correlation between the translocation and resistance and between increased susceptibility and its absence suggests that the gene(s) for adult‐plant resistance, located on the 5BS‐7BS chromosome, may be closely linked to the break point. Alternatively, it may be a consequence of the close relatedness of some of the varieties. The presence of this gene(s) might be a factor explaining the prevalence of this translocation in some West European wheats.
Sclerotinia rot resistance in red clover: Identification of RAPD markers using bulked segregant analysis
Authors: Page D. , Dulclos B. , Aubert G. , Bonavent J. F. , Mousset‐Déclas C.
Published: April 2006

Random amplified polymorphic DNA (RAPD) was used with the objective of identifying DNA markers linked to the sclerotinia crown and stem rot (SCSR) resistance of red clover. Bulked segregant analysis was used to detect polymorphism that should be linked to SCSR resistance. Two bulks were made by pooling previously extracted DNA. Each bulk (one resistant, and the other susceptible) consisted of eight genotypes from an F2 population obtained from a cross between a susceptible and a resistant parent. A binomial model was used to select RAPD fragments with a low probability of no linkage with SCSR resistance. Four RAPD fragments were retained as candidate markers of SCSR resistance. Three are associated with resistance and one with susceptibility.
Influence of sample size on precision of heritability and expected selection response in red clover
Authors: Xie C. , Mosjidis J. A.
Published: April 2006

Limited attention has been given to the effect of sample size on the precision of heritability estimates and expected selection responses. The objectives of this study were to evaluate the effect of sample size on the point estimate, its sampling error and interval width. Monte Carlo simulation and non‐parametric bootstrap were used to estimate parameters in a red clover (Trifolium pratenseL.) data set. We conducted separate analyses for two and four replications, and for combinations of six, 12, 24, 42 and 66 families, each having three, six, nine, 12 and 18 plants. Results showed that the effect of increasing number of families and replications on reduction of sampling error and interval width was greater than that of increasing plants per family. The sampling error and interval width of parameters decreased at a decreasing rate as sample size increased. To reduce the chances of having negative estimates of family variance components and to achieve a narrow confidence interval, an experiment of 42 families, each having six seedlings in four replications would be required.
Successful backcrosses of somatic hybrids betweenSinapis albaandBrassica oleraceawith theBrassica oleraceaparent
Authors: Nothnagel T. , Budahn H. , Straka P. , Schrader O.
Published: April 2006

Somatic hybrids betweenSinapis alba(2n= 24) andBrassica oleracea(2n= 18) have been backcrossed with theB. oleraceaparent. Whereas backcrosses with the diploidB. oleraceaparent were unsuccessful, 344 BC1seeds could be obtained from inter‐valence crosses with tetraploidB. oleracea(2n= 4x= 36). The investigated 96 BC1plants segregated for morphological traits and for fertility. They were backcrossed with diploidB. oleraceaor self‐pollinated, depending on their male fertility. The BC1F2and BC2progenies segregated well for the morphological traits. Disturbances were observed especially in the generative phase (flower development and pollen fertility). Both male fertile and male sterile BC1F2and BC2plants were obtained and backcrossed or self‐pollinated with theB. oleraceaparent.

The presence of either one of the parental or the cybrid organelle genomes was detected. In the progenies, a stable maternal inheritance of the organelle genome patterns was observed. Isozyme analyses revealed polymorphism for the leucine aminopeptidase (LAP) which was used for the identification ofS. albagenes in the progenies. Cytological investigations showed a clear differentiation between the BC1F2and BC2plants. Whereas the BC1F2plants possess large numbers of chromosomes ranging from 34 to 40, the BC2material was strongly reduced to chromosome numbers ranging from 20 to 22. Preliminary investigation of the meiosis suggests the possibility of introgressions ofS. alba‐DNA into theB. oleraceagenome.
Effect of host allelic dosage on Triticum aestivum–Puccinia recondita specific interaction
Authors: Tranquilli G. E. , Suárez E. Y. , Saione H. , Sacco F. , Tozzini A.
Published: April 2006

Allelic dosage changes in host‐pathogen interactions (Triticum aestivum–Puccinia recondita) explain different situations where resistance or susceptibility is observed. Remarkably, the prediction of an interaction change (from compatible to incompatible) by increasing single host allelic dosage is confirmed.

Cases of more lasting resistance could also be explained on the basis of these dosage effects. In addition a parallel between specific and nonspecific resistance is established pointing out their basic differences in expression with respect to allelic dosage effects. These situations, together with new possibilities for breeding arising from this knowledge, are discussed.
High‐lysine mutants of rice, Oryza sativa L.
Authors: Kumamaru T. , Sato H. , Satoh H.
Published: April 2006

In order to improve the nutritive value of rice protein, it is necessary to increase the level of lysine and threonine. Ten high‐lysine mutants were selected from N‐methyl‐N‐nitrosourea‐induced (MNU‐induced) mutant lines, using high‐performance liquid chromatography for amino acid analysis. The lysine content of these mutants ranged from 5.10% to 6.38% of total amino acids, while that of the original varieties was about 4%. All high‐lysine mutants also had a greatly increased histidine content and a floury endosperm. An increase in lysine content of the albumin/globulin fraction was characteristic of the MNU‐induced high‐lysine mutants. The segregation ratio of normal to floury endosperm in the F2 seeds from a cross between ‘Kinmaze’ and a high‐lysine mutant fitted the expected 3:1 ratio. The high level of lysine and the floury endosperm may be controlled by the same gene.
Introgression of a gene restoring fertility to CMS (Trachystoma) Brassica juncea and the genetics of restoration
Authors: Kirti P. B. , Baldev A. , Gaikwad K. , Bhat S. R. , Kumar V. Dinesh , Prakash S. , Chopra V. L.
Published: April 2006

A dominant gene restoring fertility to a cytoplasmic male sterile (CMS) line of Brassica juncea was derived from the somatic hybrid Trachystoma ballii+B. juncea. Its introgression resulted from forced pairing between chromosomes of the cultivar ‘Pusa Bold’ and chromosomes of the fusion hybrid. Segregation ratios of this fertility restorer gene followed a monogenic pattern. The introgression of the fertility restorer gene did not cause any abnormalities, such as reduced fertility; pollen and seed fertilities of the restored plants were over 90%. Restored fertile and CMS plants exhibited similar Southern hybridization patterns when probed with the mitochondrial probe atp6.
Inheritance and linkage of a gene for testa‐imposed seed dormancy in faba bean (Vicia faba L.)
Authors: Ramsay G.
Published: April 2006

Seed dormancy in the grain legumes may interfere with germination in some situations, yet is not well described. Dormancy in faba bean (Vicia faba L.) was investigated to determine the mode of inheritance and whether the gene or genes controlling this trait are linked to other genes. Seeds produced by 235 recombinant inbred lines at the F6 generation were used for this study. The parents were the cultivar ‘Optica’ and 172, an Afghanistan landrace which possesses extended seed dormancy. Germination was scored on a seed sample from each recombinant inbred line. Segregation patterns indicated that the trait is monogenic. This gene, named doz, is linked to a gene controlling anthocyanin and proanthocyanidin synthesis, sp‐b, with the genetic distance estimated to be about 25 cM. No associations were detected between seed dormancy and pod dehiscence, seed lustre or mean seed weight. The implications of the persistence of a gene for seed dormancy in the gene pool of V. faba for the introgression of traits from landraces and cultivars possessing dormancy and for the origins of domesticated V. faba are discussed.
Drought tolerance screening for potato improvement
Authors: Ranalli P. , Candilo M. di , Bagatta M.
Published: April 2006

Six potato genotypes including ‘Desiree’ and five breeding clones (2/14, 95C, 125B, 3589, 4056) were grown in the field under well‐watered and stress conditions. The stress response of leaf tissue was assessed 8 and 12 weeks after plant emergence (WAE) by measuring canopy temperature and chlorophyll α fluorescence induction kinetics in detached leaves. Under drought‐stress conditions, chlorophyll α fluorescence dropped in clones 2/14 and 4056, remained constant in 95C and 125B and increased in clone 3589. The canopy temperature exhibited little difference between drought and irrigated treatments in clones 95C and 125B, and significant effects in the other genotypes. This performance was interpreted in terms of tolerance to drought stress, and the potential use of canopy temperature and chlorophyll fluorescence as tools for drought screening of potato germplasm and segregant generations is discussed. The physiological properties of 95C and 125B highlighted by this study need further investigation and, if confirmed, they could be recombined with other useful agronomic characters by crossing in a breeding programme.
Effectiveness of selection at microtuber crop level in potato
Authors: Gopal J. , Minocha J. L.
Published: April 2006

Correlation coefficients were computed between microtuber crops and normal seed crop in order to study the selection efficiency for agronomic characters in potato at microtuber crop level. Two types of microtuber, green and white, were produced by inducing microtuberization under light and dark conditions, respectively. Genotypic differences were significant for various characters in both microtuber and normal seed crops. Green and white microtubers were equally useful for selection, judging by the crops raised from them. Selection at microtuber crop level was found to be highly effective for plant height, stem habit, tuber colour and general impression, and moderately effective for internode length, leaf length, leaflet width, stem pigment, plant vigour and tuber shape. Selection efficiency was low for tuber yield, tuber number, average tuber weight, number of nodes, number of stems, leaf colour and number of eyes. The implications of these results for potato breeding and germplasm evaluation programmes are discussed and a procedure for selecting superior genotypes at microtuber crop level is outlined.
Doubled haploid production in Turkish durum wheats using crosses with maize
Authors: Savaskan C. , Ellerbrook C. , Fish L. J. , Snape J. W.
Published: April 2006

Durum wheats cultivated in the Middle Anatolia region of Turkey (Triticum durum cvs ‘Kunduru’, ‘Berkmen’ and ‘Cakmak’) were crossed with maize to evaluate their capacity for haploid embryo and doubled haploid (DH) plant production. A total of 2960 florets were crossed with maize and 13.7% of the florets produced haploid embryos across the three varieties. Haploid embryo and plant regeneration frequencies were highest in ‘Kunduru’, but colchicine doubling was less successful with this genotype. There were statistically significant differences between ‘Cakmak’ and other genotypes for embryo yield (P < 0.01). Overall, 52.3% of all embryos differentiated, but there were no geno‐typic differences in differentiation frequencies.
Fertility restoration of new CMS sources in sunflower (Helianthus annum L.)
Authors: Horn R. , Friedt W.
Published: April 2006

The development of commercial sunflower hybrids based on new CMS sources is of special interest for reducing the potential risk of vulnerability to pathogens and for increasing genetic diversity. From 263 test crosses involving nine new CMS sources, i.e. ANL1, ANL2, MAX1, PEF1, PET2, ANN1, ANN2, ANNS and ANN4, five lines were selected as potential restorers for PEF1, PET2 and ANN4. In test crosses between all nine CMS sources and these five restorer lines evaluated in 2 years, seven fully restored hybrids could be identified. These hybrids, based on ANL1, ANL2, MAX1, PEF1, PET2, and ANN4, showed good agronomic performance for plant height, days to flowering, maturity and oil content. Segregation analyses of the F2 populations indicate that a single dominant restorer gene was sufficient to restore pollen production of hybrids based on ANL2, PEF1 and PET2. For restoration of ANN4, two dominant complementary genes are required. In restoration of fertility in the crosses of ANL1 and MAX1 investigated, two dominant genes are involved each of which on its own allows the production of fertile plants.
Effects of D‐genome chromosomes on crossability of hexaploid triticale (X Triticosecale Wittmack) with maize
Authors: Inagaki M. N. , Pfeiffer W. H. , Mergoum M. , Mujeeb‐Kazi A. , Lukaszewski A. J.
Published: April 2006

With the aim of producing polyhaploids of hexaploid triticale, 20 genotypes from a CIMMYT breeding programme and eight D‐genome chromosome substitution lines of ‘Rhino’ were crossed with maize. In crosses between 20 triticale genotypes and maize, 15 lines produced embryos. Frequencies of embryo formation ranged from 0.0 to 5.4%, with an average of 1.1%. From a total of 200 pollinated spikes, 62 plants were regenerated. Most regenerated plants were polyhaploids with 21 chromosomes, and few aneuhaploids with 22 chromosomes were found. In crosses of triticale substitution lines with maize, all the lines produced embryos, while ‘Rhino’ produced no embryos at all. Higher frequencies of embryo formation were obtained in substitution lines with chromosomes 2D and 4D. These results suggest that D‐genome chromosomes in a triticale genetic background have the effect of increasing the frequency of polyhaploid production in triticale x maize crosses.
Molecular markers linked to rhizomania resistance in sugar beet, Beta vulgaris, from two different sources map to the same linkage group
Authors: Giorio G. , Gallitelli M. , Carriero F.
Published: April 2006

Rhizomania, one of the most important diseases of sugar beet, is caused by beet necrotic yellow vein virus, a Furovirus vectored by the fungus Polymyxa betae Keskin. Reduction of the production losses caused by this disease can only be achieved by using tolerant cultivars. The objective of this study was the identification and mapping of random amplified polymorphic DNA (RAPD) markers linked to a rhizomania resistance gene. The RAPD markers were identified using bulked segregant analysis in a segregating population of 62 individuals derived by intercrossing plants of the resistant commercial hybrid GOLF, and the resistance locus was positioned in a molecular marker linkage map made with a different population of 50 GOLF plants.

The resistance locus, Rr1, was mapped to linkage group III of our map of Beta vulgaris L. ssp. vulgaris, which consisted of 76 RAPDs, 20 restriction fragment length polymorphisms (RFLPs), three sequence characterized amplified regions (SCARs) and one sequence tagged site (STS). In total, 101 molecular markers were mapped over 14 linkage groups which spanned 688.4 cM with an average interval length of 8.0 cM. In the combined map, Rr1 proved to be flanked by the RAPD loci RA4111800 and AS71100 at 9.5 and 18.5cM, respectively. Moreover, in our I2 population, we found that a set of markers shown by Barzen et al. (1997) to be linked to the ‘Holly’ type resistance gene was also linked to the ‘GOLF’‐type resistance gene. These results appeared to indicate that the rhizomania resistance gene present in the GOLF hybrid could be the same gene underlying resistance in ‘Holly’‐based resistant genotypes. Two other explanations could be applied: first, that two different alleles at the same locus could have been selected; second, that two different genes at two different but clustered loci underwent the selection process.
Molecular characterization of fertile and sterile cytoplasms in Beta spp.
Authors: Sadoch Z. , Goc A.
Published: April 2006

Mitochondrial DNA (mtDNA) from sugar beet carrying fertile (F) and male sterile (CMS) cytoplasms, and from male sterile accession of Beta maritima collected in Brittany (France) were characterized and compared by restriction fragment length polymorphism (RFLP) and Southern hybridization with coxII. The F and CMS cytoplasms could be clearly distinguished from each other by RFLP when XhoI, EcoRI and BamHI endonucleases were used. Southern hybridization with the coxII gene provided further evidence that mitochondrial genome organization differs between fertile and sterile plants. All cytoplasmic male sterile lines from different breeding stations showed the same restriction and hybridization patterns, which confirms the uniformity of mitochondrial genomes within the materials used for hybrid seed production in several European countries. No visible differences were found between the maintainer lines studied. However, comparisons of XhoI restriction profiles of mtDNA from maintainer lines and from fertile monogerm populations revealed slight differences, which were reflected by the appearance of a unique 0.9 kb fragment in the latter.

Analysis of mtDNA from male sterile plants of the wild beet B. maritima showed different restriction and hybridization patterns in comparison with normal and sterile sugar beet cytoplasms. This shows the unique nature of cytoplasmic male sterility in this species.
Genetic variation among European maize inbreds for resistance to the European corn borer and relation to agronomic traits
Authors: Schulz B. , Kreps1 R. , Klein D. , Gumber R. K. , Melchingeru A. E.
Published: April 2006

The univoltine European corn borer (ECB) has become a major limiting factor for maize (Zea mays L.) production in central Europe. The objective of this study was to survey the genetic variation for ECB resistance in European elite maize germplasm. Eighteen flint and 23 dent inbreds were screened under artificial ECB infestation at two locations in 1993 and 1994. Resistance was assessed by damage rating of broken plants, measurement of tunnel length in dissected stalks, and yield reduction in infested plots relative to insecticide‐protected control plots. Flint lines showed significantly greater means for damage rating than dent lines with grain yield reduction of 35% and 24%, respectively. Significant genotypic variances among lines and high heritabilities were found for agronomic traits and damage rating. Heritabilities were intermediate for tunnel length and relative grain yield. Significant associations of days to silking, ear dry matter content, and dry matter yield of the whole plant with damage rating and tunnel length suggested a better resistance in late‐maturing, high‐yielding inbreds. Genotypic correlations of relative grain yield with tunnel length and damage rating ranged between −0.46 and −0.72. Partial correlations, eliminating the effect of flowering time, confirmed these associations. Damage rating of stalks is the most suitable trait for evaluation of ECB damage owing to its high heritability and easy recording. Tunnel length below the primary ear is a useful trait for assessing antibiosis because it is not correlated with days to silking. Inbreds with extreme resistance and susceptibility were identified which can be used as parents for establishing breeding and QTL mapping populations.