bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screening for resistance to broomrape (Orobanche cernua) in cultivated sunflower
Authors: Dominguez J. , Melero‐Vara J. M. , Miller J. , Fernández‐Martinez J. M. 
Published: April 2006

AbstractRacial evolution of sunflower broomrape (Orobanche cernua) has been very rapid in Spain during recent years, in which resistance has been overcome several times and there has been an important increase in areas infested with this parasitic angiosperm. In order to find resistance to a highly virulent population of sunflower broomrape that could be used directly in breeding programmes, three different sets of cultivated plant material composed of 429 entries were tested by artificial inoculation. All evaluated inbred lines from Moden, Canada, were fully susceptible. Out of the 240 P.I. accessions tested, only 10 segregated for resistance to broomrape, the rest being susceptible. From the 160 USDA breeding lines evaluated, 5% were resistant and 19% segregated for resistance to O. cernua. These lines traced back mainly to crosses of RHA 274 and RHA 801 with Russian, Turkish and Romanian hybrids. The origin of P.I. accessions that segregated for resistance were primarily derived from the former USSR and from Romania.
Improved RAPD amplification of recalcitrant plant DNA by the use of activated charcoal during DNA extraction
Authors: Bi I. Vroh , Harvengt L. , Chandelier A. , Mergeai G. , Du Jardin P. 
Published: April 2006

AbstractAn efficient procedure has been developed for DNA extraction from cotton by modifying the original CTAB method. The major improvement concerns the use of activated charcoal to bind resinous and coloured compounds which copurify with the DNA. The efficiency of amplification by RAPD was used as a criterion to evaluate the action of activated charcoal. Twenty‐five random decamers from Operon Technologies were used to compare DNA samples extracted in the presence or absence of activated charcoal. The results in terms of amplification suggest that the use of activated charcoal in DNA extraction enhances RAPD amplification. This technique was initially developed for cotton but it has been applied successfully to other recalcitrant plants such as coffee, rubber tree, cassava and banana.
Impact of low linolenic acid content on seed yield of winter oilseed rape (Brassica napus L.)
Authors: Rücker B. , Röbbelen G. 
Published: April 2006

AbstractAn essential quality improvement of rapeseed oil can be obtained by reduction of its linolenic acid (C18:3) content from about 10% to less than 3% of the total fatty acids. Genotypes low in C18:3 have been developed by mutagenesis. The initial summer rapeseed mutant had been low yielding and highly susceptible to various diseases. It has been debated whether the low C18:3 character can be successfully combined with high seed yield for physiological reasons. Therefore, the low linolenic character of mutant M48 was transferred into high‐yielding genotypes by repeated backcrossing to well‐adapted low erucic acid, low glucosinolate (00‐) winter rapeseed cultivars. Lines with low C18:3 content were selected from BC3 and BC4 generations and examined in 1990–95. Positive selection response for seed yield was shown to continue over the years. Presently, the best lines are yielding as well as the control cultivars being equivalent also in oil and glucosinolate contents.In order to test the effect of a low C18:3 content on seed yield, plants with low and with high C18:3 content, respectively, were selected from 16 segregating BC5‐F2 populations and bulked to form 32 F3 populations. These ‘isogenic’ bulk populations were tested for field performance at four locations in 1995. The results show that C18:3 content of the seed oil is not associated with seed yield, oil content, beginning of flowering, plant height and disease resistance. Means of relative seed yield for the high and the low linolenic F3 bulk populations were not significantly different with 88.0% and 86.9% of the control cultivars, respectively. There was a significant interaction between genotypes with high or low C18:3 content and location. This shows that under specific environmental conditions a low C18:3 content may be either favourable or unfavourable. The results indicate that the low C18:3 character of the original mutants per se does not cause a decrease in seed yield, oil content or general field performance.
First in vivo assessment of feeding value of Festulolium hybrids derived from Festuca arundinacea var. glaucescens and selection for palatability
Authors: Ghesquière M. , Emile J.‐C. , Jadas‐Hécart J. , Mousset C. , Traineau R. , Poisson C. 
Published: April 2006

AbstractThis paper reports on the first results of feeding value experiments, assessed with sheep, of hybrids between tetraploid Italian ryegrass (Lolium multiflorum, 2n = 4×= 28) and a progenitor of tall fescue, Festuca arundinacea var. glaucescens (2n = 4×= 28). Three hybrid populations resulting from either high, low or no selection for palatability were compared with a variety of Italian ryegrass as control and two varieties of the cultivated hexaploid (2n = 6×= 42) tall fescue, one of which had been selected for high palatability. On average, the hybrid populations were found to be as palatable as the improved tall fescue with voluntary intake (VI), in vivo digestibility of organic matter (DOM), and net energy expressed in fodder units for milk, similar to the best palatable tall fescue and to Italian ryegrass. However, selection for improved palatability among hybrids did not result in any further improvement of other traits, except VI in the hybrid selected for high palatability which significantly exceeded VI of Italian ryegrass. In conclusion, intergeneric hybridization between L. multiflorum and F. arundinacea var. glaucescens led to an immediate increase of feeding value compared with selection for palatability in tall fescue. However, to improve feeding value of hybrids further, similar selection for high palatability appeared questionable and possibly detrimental for other agronomic traits because of complicated inheritance in tetraploid L. multiflorum×F. glaucescens hybrids.
Genetic analysis of salt tolerance during vegetative growth in tomato, Lycopersicon esculentum Mill.
Authors: Foolad M. R. 
Published: April 2006

AbstractBreeding for salt tolerance in tomato has been impeded by insufficient knowledge of the genetic control of tolerance. The genetic basis of salt tolerance during vegetative growth was investigated by growing a salt‐tolerant (PI174263) and a salt‐sensitive tomato cultivar (UCT5) and their F1, F2 and backcross progeny in saline solutions with electrical conductivity of 0.5 (control) and 20 dS/m (salt‐stress). The relative salt‐tolerance of each generation was determined as the percentage of growth (i.e. dry matter production) under salt‐stress relative to growth under control conditions. In all generations, shoot growth was significantly reduced by salt stress. The reduction was largest in UCT5 (56.1%) and smallest in the F1 (27.4%), followed by PI174263 (32.3%). Analysis of the absolute and relative growth under salt‐stress indicated that genes contributing to vigour might be different from genes conferring tolerance. Generation means analyses of the absolute and relative growth indicated that the majority of the genetic variation among generations were due to simple (additive and dominance) genetic effects; nonallelic interactions, although significant, were far less important. Partitioning of the total genetic variance by weighted least‐square regression analysis and variance component analysis indicated that 88% or more of the variation was due to additive genetic effects. A moderate estimate of narrow sense heritability (0.49 ± 0.09) was obtained for shoot DW under salt‐stress treatment. The results indicate that tomato salt‐tolerance during vegetative growth can be improved by breeding and selection.
Efficient hybridization between Lycopersicon esculentum and L. peruvianum via ‘embryo rescue’ and in vitro propagation
Authors: LanZhuang Chen , Adachi Taiji 
Published: April 2006

AbstractFor the transfer of valuable traits from wild species into the cultivated tomato, excised globular‐stage embryos 13 and 15 days after pollination (DAP) were cultured in vitro. Plants were regenerated from interspecific crosses of Lycopersicon esculentum cv. ‘Early pink’×L. peruvianum PI270435, and backcrosses of L. esculentum‘Giban (JF) No. 1’× (‘Early pink’× PI270435). Somatic embryos and single cotyledons emerged on hypocotyl sections of the embryos. Five to nine plantlets per embryo were obtained by clonal propagation. The hybrid nature of the plants is confirmed by comparing hybrids and parents in their ability to regenerate shoots from leaf segments in vitro, by comparing plant morphology and characteristics and by chromosome number. This study describes an efficient ‘embryo rescue’ method, as well as somatic embryogenesis by clonal propagation. A novel and simple method for the characterization of the interspecific hybrids is also reported.
Single‐gene resistance to Septoria tritici blotch in the spring wheat cultivar ‘Tadinia’
Authors: Somasco O. A. , Qualset C. O. , Gilchrist D. G. 
Published: April 2006

AbstractResistance to Mycosphaerella graminicola causal agent of Septoria tritici blotch, was identified in progenies of crosses with European winter wheat cultivars, Tadorna and Cleo. This resistance was used to develop the resistant spring wheat cultivar Tadinia, selected from ‘Tadorna’/‘Inia 66’ released in 1985. Evaluation of the progeny of intercrosses between ‘Tadorna’, ‘Cleo’, ‘Tadinia’, and two short‐statured resistant lines derived from hybrids with ‘Tadinia’ as one parent indicate the resistance was inherited as a single gene showing partial to strong dominance. The gene in ‘Tadinia’ was designated Stb4. Crosses between another resistant cultivar, ‘Bulgaria 88’, and ‘Tadinia’ suggest that ‘Bulgaria 88’ does not have Stb4. Successful introgression of Stb4 into Rht1+Rht2 short‐statured lines revealed that plant stature and resistance to M. graminicola segregated independently. The Stb4 gene has been effective since 1975 against M. graminicola extant in California. A high positive correlation between seedling and adult plant disease scores, based on scoring of lesions producing pycnidia, indicated that the Stb4 gene is expressed throughout the life cycle under both field and greenhouse conditions, confirming that disease screening can be carried out on seedling plants. Separate assessment of necrotic lesions with and without pycnidia indicated that leaf necrosis without pycnidia, observed, especially under greenhouse conditions, can confound disease evaluations and lead to inaccurate genotype classification.
Linkage relations among eyespot resistance gene Pch2, endopeptidase Ep‐A1b, and RFLP marker Xpsr121 on chromosome 7A of wheat
Authors: de la Peña R. C. , Murray T. D. , Jones S. S. 
Published: April 2006

AbstractMarker‐based selection of Ep‐D1b has been used successfully to incorporate Pch1, the gene for eyespot resistance on chromosome 7D, into commercial wheat. However, attempts to transfer resistance conferred by Pch1 (on chromosome 7A) through selection for Ep‐A1b have not always been successful. Linkage relations among eyespot resistance gene Pch2, a gene encoding for an isozyme of endopeptidase, Ep‐A1b, and RFLP marker Xpsr121 on chromosome 7A were determined using 80 homozygous recombinant substitution lines. The recombinant lines were derived from eyespot susceptible ‘Chinese Spring’ hybridized with a resistant disomic substitution line of ‘Cappelle Desprez’ that has chromosome 7A substituted into ‘Chinese Spring’. Segregations of Pch2, Ep‐A1b and Xpsr121 fit an expected 1:1 single‐locus ratios based on χ2 tests. Linkage analysis revealed that Pch2 was not tightly linked to Ep‐Alb (15% recombination). However, close linkage (3.8% recombination) existed between Ep‐A1b and Xpsr121. The order of these loci is Pch2‐Xpsr121‐Ep‐A1b. Unlike Pch1 and Ep‐D1b, where little or no recombination is found, Pch1 and Ep‐A1b showed considerable recombination and therefore linkage cannot be utilized efficiently in marker‐based selection.
First report of leaf rust pathotypes virulent to highly effective Lr‐genes transferred from Agropyron species to bread wheat
Authors: Sibikeev S. N. , Krupnov V. A. , Voronina S. A. , Elesin V. A. 
Published: April 2006

AbstractThe gene pool of effective sources of leaf rust resistance used in the breeding of wheat (Triticum aestivum L.) includes several species of the genus Agropyron. The genes deriving therefrom (Lr 19, 19d, 29, Agi1, Agi2, 38) are highly effective to pathotypes of Puccinia recondita Rob. ex Desm. In the Saratov and Orenbhurg districts of Russia, however, pathotypes virulent to these genes have been discovered. These pathotypes are virulent to Saratov‐bred cultivars carrying Lr 19, to ‘Indis’ (Lr 19d) and RL 6097 (Lr 38). The distribution of virulence on the ‘Thatcher’ near‐isogenic lines with different Lr genes shows that most of the Lr genes tested are susceptible to these new pathotypes of P. recondita, but the Lr genes Lr 9, 23, 24, 26 were exceptions. The inoculation of Mexican bread wheat cultivars, which carry widespread Lr gene combinations, by these pathotypes disclosed different infection types. Out of 10 Lr‐gene combinations, four were highly effective; namely the combinations Lr 13 + 26, Lr 26 +?, Lr 23+26 and Lr 23+26+34.
Utilization of deletions to localize a gene for resistance to the cereal cyst nematode, Heterodera avenue, on an Aegilops ventricosa chromosome
Authors: Jahier J. , Tanguy A. M. , Abelard P. , Rivoal R. 
Published: April 2006

AbstractA previous RFLP analysis showed that the Aegilops ventricosa chromosome 6MV which compensates for the absence of 6D in 6MV (6D) wheat substitution lines was a 2/6 translocated chromosome, either 2S–6S.6L or 2S–6L.6S. The distal part of its long arm consists of a translocated segment belonging to homoeologous group 2. Chromosome 6MV carries a gene(s) for resistance to cereal cyst nematode. In order to define the part of 6MV (2S or 6S or 6L) involved in this resistance, addition lines with a 6MV deleted either for its short arm or for the distal part of its long arm were evaluated. It was shown that the gene(s) is carried by the group 2 translocated segment. The hypothesis that the gene(s) could be allelic to Cre2, another gene conferring resistance to the nematode introduced into the wheat complement from Ae. ventricosa is discussed.
RAPD‐mapping of the distal portion of chromosome 3 of barley, including the BaMMV/BaYMV resistance gene ym4
Authors: Weyen J. , Bauer E. , Graner A. , Friedt W. , Ordon F. 
Published: April 2006

AbstractExperiments were carried out in order to identify RAPD‐markers for the BaMMV/BaYMV resistance gene ym4 to facilitate efficient marker‐based selection in practical breeding programmes. Linkage analysis was carried out with 283 doubled haploid (DH) barley lines out of a cross between the BaMMV/BaYMV susceptible cv. ‘Igri’ and the resistant cv. ‘Franka’. Using bulked segregant analysis, 310 RAPD‐primers were screened for polymorphism between the parents. Four of these primers gave rise to specific bands linked to the resistance gene ym4.
A comparison of somaclonal variation in rice plants derived and not derived from protoplasts
Authors: Yamagishi M. , Otani M. , Shimada T. 
Published: April 2006

AbstractTo clarify the effect of the type of in vitro culture on the generation of somaclonal variation, protoplast‐derived rice plants were compared with rice plants derived from suspension culture or primary calli (not derived from protoplasts). Regenerated plants showing polyploid‐like phenotypes appeared at a higher frequency (33–70%) in plants derived from protoplasts than in those not derived from protoplasts (3–6%). In the first progeny (R1) generation of all regenerated plants, 120 of 368 lines (33%) segregated plants with mutated characters such as albino, dwarf and sterile. In quantitative traits, 62 (21%) and 144 (50%) of 290 Rj lines showed shorter culm and lower seed‐fertility, respectively, compared with the control line derived from the selfed seeds of the original cultivar. The frequency of the mutant‐possessing R1 lines among lines derived from protoplasts was not significantly different from those not derived from protoplasts. These results indicate that isolation and culture of protoplasts does not enhance genetic changes other than cytogenetical changes.
A genetic analysis of low‐temperature‐sensitive sterility in indica‐japonica rice hybrids
Authors: Li H. B. , Zhang Q. , Liu A. M. , Zou J. S. , Chen Z. M. 
Published: April 2006

AbstractLow‐temperature‐sensitive sterility has become one of the major obstacles in indica–japonica hybrid rice breeding. The objectives of this paper were to evaluate the extent of the fertility reduction and to determine the genetic basis of low‐temperature‐sensitive sterility. Seventeen varieties were crossed in various ways to produce 21 F1s including 16 indica‐japonica hybrids. Fertility of the F1s and their parents was examined under both high and low temperature conditions. Considerable reduction in spikelet fertility was observed under low‐temperature conditions in the majority of the indica–japonica hybrids having at least one wide compatibility parent. However, the extent of fertility reduction varied greatly, depending on the parental genotypes. Data from five pairs of reciprocal crosses indicated that the cytoplasm had no effect on fertility reduction. The more‐or‐less bimodal distribution of the fertility segregation of one BC1F1 and two F2: populations under low‐temperature conditions suggested that the low‐temperature‐sensitive sterility was controlled by only one or a few genes. It was also shown that the low‐temperature‐sensitivity is not related to wide compatibility. We conclude that it is possible to develop indica‐japonica hybrids with wide compatibility and also insensitivity to the low‐temperature conditions.
Quantitative trait loci influencing grain protein content in tetraploid wheats
Authors: Blanco A. , Giovanni C. de , Laddomada B. , Sciancalepore A. , Simeone R. , Devos K. M. , Gale M. D. 
Published: April 2006

AbstractSeed storage protein content of durum wheat (Triticum turgidum var. durum) has an important effect on nutritional value and pasta‐making characteristics. The objective of this study was to determine by association with genetic markers the number, chromosomal location, and magnitude of effect of quantitative trait loci (QTLs) controlling protein concentration in kernels. A set of 65 recombinant inbred lines (RIs) was developed by single seed descent from a cross between cultivated durum wheat cv. ‘Messapia’ (low protein content) and accession MG4343 of the wild tetraploid wheat var. dicoccoides (high protein content). This population was characterized for eight morphological, six storage protein, one isozyme and 124 RFLP loci. Field trials were conducted in one location in 1993 and two locations in 1994. QTLs were mapped by regression analysis on each marker locus for each location and for the average across environments. A total of six putative QTLs were located on chromosome arms 4BS, SAL, 6AS, 6BS and 7BS. The number and size of QTLs detected varied across environments. The marker with the highest r2 value per QTL in each environment and across environments was chosen for a multiple linear regression analysis, which explained 49.2‐ 56.4% of the phenotypic variation for protein content. Only some of the markers were found to be negatively associated with plant grain yield and/or seed weight in one or two of the environments.
Genotypic variation for competitive ability in spring wheat
Authors: Huel D. G. , Hucl P. 
Published: April 2006

AbstractHerbicides are the primary method of weed control for crop production in developed countries. For economic and environmental reasons alternative control strategies are being devised. One of these strategies is the development of competitive crop cultivars. The objectives of this research were to establish whether spring wheat (Triticum aestivum L.) genotypes differed in competitive ability and if those differences were related to specific growth characteristics. Sixteen genotypes of spring wheat were grown under simulated weed competition conditions at Saskatoon, Canada over a 3–year period. Four high and four low tillering genotypes from each of two crosses (Neepawa/M1417 and Ingal/M1417) were studied. Weeds consisted of cultivated oat (Avena saliva cv. ‘Waldern’) and oriental mustard (Brassicajuncea cv. ‘Cutlass’) sown at two densities (48 and 96 seeds/m2 per weed species). Seedling establishment, ground cover, and seed yield for the three species were determined, as was wheat tiller number, spike number, maximum height, leaf area index, leaf orientation, and flag leaf length and size. Significant (P = 0.001) weed rate by genotype interactions involving changes in genotype rank were detected for wheat grain yield, indicating that the 16 wheat genotypes differed in competitive ability. Wheat grain yield reductions averaged over the two weed densities ranged from 45% to 59%. The highest‐yielding genotypes under weed‐free conditions were not necessarily the highest yielding under weedy conditions. Genotypes which suffered smaller yield reductions were more effective in suppressing weed growth. Although competitive genotypes were generally taller than non‐competitive genotypes, other traits such as large seedling ground cover and flag leaf length were associated with wheat yield under competitive conditions.
Sequential path analysis of grain yield and its components in maize
Authors: Agrama H. A. S. 
Published: April 2006

AbstractThe efficiency of a breeding programme depends mainly on the direction and magnitude of the association between yield and its components and also the relative importance of each factor involved in contributing to grain yield. The purpose of this research is to describe the application of causal path analysis to grain yield in maize (Zea mays L.) to take into account the sequential development of yield components. Causal‐admissible path analysis was performed assuming unidirectional causal relationships among yield components of eight maize populations. Sequential path analysis of the five yield components studied revealed that ears per plant had the highest direct effect on grain yield. However, the indirect effects of component traits via number of grains per ear was maximum. It was concluded that the number of kernels per ear, prolificacy, and grain size serve as potential characters in breeding for superior lines for grain yield in maize.