bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractTwenty‐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

AbstractChromosome 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

AbstractAll 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

AbstractWild 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

AbstractIdentification 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

AbstractThe 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.
Evidence for common genetic mechanisms controlling the tolerance of sudden salt stress in the tribe Triticeae
Authors: Zhong Gan‐Yuan , Dvořák Jan 
Published: April 2006

AbstractPrevious studies in several Triticeae species have suggested that salt tolerance is a polygenic trait, but that genes on some chromosomes confer better tolerance to salt stress than others. This suggests an intriguing possibility that there may be a similar basis for salt tolerance in the species of the tribe Triticeae. In this study, chromosomal control of the tolerance to sudden salt stress, measured as the mean rate of leaf elongation in solution cultures with a single increment of 200 mM NaCl, was investigated in the genomes of cultivated barley (Hordeum vulgare L.), rye (Secale cereale L.), and Dasypyrum villosum (L.) Can‐dargy by using disomic addition lines of individual pairs of chromosomes or chromosome arms of each of the three species in the ‘Chinese Spring’ wheat genetic background. It was observed that the chromosomes of homoeologous groups 3, 4, and 5 in barley, 5 and 7 in rye, and 4 and 6 in D. villosum carry loci with significant positive effects on salt tolerance. Increased doses of chromosomes of group 2, however, reduce or do not increase the tolerance to salt stress. These results are in agreement with a previous study of the tolerance of this salt stress regime in wheat and wheatgrass Lophopyrum elongatum. A ranking analysis of the chromosomal effects within each genome of the five Triticeae species investigated in this and previous studies revealed that the chromosomes of homoeologous groups 3 and 5 consistently confer large positive effects on the tolerance of sudden salt stress, while the chromosomes of homoeologous group 2 in increased dose have no or negative effects on the tolerance. This strongly suggests that species of the tribe Triticeae share some common genetic mechanisms of tolerance of sudden salt stress. The findings in this study give credence to the proposal that wild relatives can be exploited in the development of wheat cultivars with greater tolerance to salt stress.
In vitro breeding of high‐linolenic, doubled‐haploid lines of linseed (Linum usitatissimum L.) via androgenesis
Authors: Friedt W. , Bickert C. , Schaub H. 
Published: April 2006

AbstractIn the course of a breeding programme for high‐linolenic‐acid linseed (oilflax, Linum usitatissimum L.) doubled‐haploid lines (DH‐lines) of three F1 hybrids were generated using an anther‐culture technique. A total of 82 DH‐lines were generated and multiplied in 1993, of which 39 were suitable for testing in a repeated field trial in 1994. Yield, fat content and fatty‐acid composition were determined. The yield of the DH‐lines was not significantly different from that of respective mid‐parent values. Fatty‐acid composition and fat content showed remarkable variation, and DH‐lines exceeded cross parents in some cases for both fat content and linolenic‐acid proportion. Superior DH‐lines surpassed mid‐parent linolenic‐acid‐content values by 4.5% and fat content by 1.9%. The results indicate that anther culture is a useful tool in linseed breeding.
Genetic variation and control of plant regeneration in leek (Allium ampeloprasum L.)
Authors: Silvertand B. C. H. J. , Jacobsen E. , van Harten A. M 
Published: April 2006

AbstractZygotic embryos of leek (Allium ampeloprasum L.) were isolated from mature seeds of different cultivars, selfings and full‐sib families. The embryos were cultured on callus induction and shoot regeneration medium and employed to study several parameters: percentage of embryos forming calluses, percentage of embryos forming compact calluses, callus weight, percentage of regenerating calluses, numbers of shoot primordia and numbers of regenerated shoots. Differences between cultivars and selfings were found for most parameters studied. For all cultivars all parameters, except callus weight, decreased after one generation of selfing. Compact callus types enhanced primordia formation and shoot regeneration. Genetic characteristics of callus development and plant regeneration were studied in a 4 × 4 diallel cross. Analysis of variance revealed significant differences between full‐sib families. The diallel analysis showed that additive gene effects were significant for all parameters. The predominance of additive gene effects indicated high narrow‐sense heritability. Breeding for an increased number of regenerated shoots was successful.
Direct plant regeneration from leaf explants in cucumber (Cucumis sativus L.) is free of stable genetic variation
Authors: Burza W. , Malepszy S. 
Published: April 2006

AbstractA new procedure is described for rapid and efficient plant regeneration from leaf explants of Cucumis sativus and C. anguria. The following factors were most important: young leaves, the NO3: NH4 ratio in the plant induction medium, small explants and the growth regulator combination. After about 4 weeks of culture under optimal growth conditions, the frequency of regeneration was 10–100% of explants. Six to 7 weeks were required to obtain well‐rooted plants, which were mostly able to survive after transfer into soil. From a single young leaf of C. sativus cv. ‘Borszezagowski’, 135 plants could be regenerated. All plants transferred to a greenhouse were free of morphological or physiological abnormalities, flowered normally and bore fruits. The analysis of R0 plants showed no genetic variation, whereas in the R1 two new phenotypes, which were not transmittable to the R2, were observed. This procedure is recommended for its production of homogeneous cucumber plants.
Two host genes in Vicia faba for nodulation deficiency with strain specificity for Rhizobium leguminosarum
Authors: Esser‐Mönning K. , Roskothen P. , Röbbelen G. 
Published: April 2006

AbstractIn greenhouse tests, two inbred lines of faba bean, I 40 and I 25, proved to be nodulation resistant and F2 progenies were used to determine the genetic control of this nodulation deficiency. The defect is strain‐specific for the Rhizobium strains St 48 and St 53. In inbred line I 40, the deficient nodulation character is controlled by a dominant gene which is called Sym‐2, while another recessive gene sym‐3 is assumed for line I 25; Sym‐2 is epistatic over sym‐3.
Association between resistance to Cercospora and yield in commercial sugarbeet hybrids
Authors: Smith G. A. , Campbell L. G. 
Published: April 2006

AbstractThis report documents the difficulty breeders have experienced in combining resistance to Cercospora leaf spot (causal agent Cercospora beticola Sacc.) with high yield in sugarbeet (Beta vulgaris L.). Forty commercial hybrids, all recommended for Cercospora‐threat areas, were grown in a Cercospora‐free and a diseased (inoculated) environment in 1991 and 1992. A 2.9 Mg/ha decrease in root yield associated with each increment increase in susceptibility confirmed that under a severe epiphytotic (1991) Cercospora resistance provided substantial protection. Under less‐severe disease conditions (1992) there was no apparent relationship between yield and resistance, suggesting that the benefits of resistance were similar to the yield potential sacrificed to obtain the resistance. In the absence of the disease, root yields increased 2.7 Mg/ha for each increment of increased susceptibility. There was no evidence of association between sucrose concentration and resistance in the Cercospora‐free environment. Despite the limited efforts and/or success in developing resistant commercial hybrids, the demonstrated ability of Cercospora to produce fungicide‐resistant strains and the possibility that effective fungicides will not be available provide incentives to seek genetic resistance through breeding efforts.
Application of quantitative trait locus mapping to the development of winter‐habit malting barley*
Authors: Oziel A. , Hayes P. M. , Chen F. Q. , Jones B. 
Published: April 2006

AbstractMalting quality and winter‐hardiness in barley are ‘ultimate’ phenotypes composed of constituent quantitatively inherited traits. A synthesis of molecular‐marker linkage data and field phenotyping to reveal the location of quantitative trait loci (QTL) may assist in the development of winter‐habit malting barley varieties. One‐hundred doubled haploid progeny from a winter x spring cross were evaluated under fall and spring‐planted conditions. Malting quality phenotypes and a 76‐point map were used to identify QTL and to assess the effect of spring‐and autumn‐sowing on QTL expression. Many QTL effects were common to both environments and corresponded to QTL detected in other barley germplasm. While there were significant differences in the magnitude of effects across environments, there were no changes in the favourable allele phase. QTL effects for grain protein and diastatic power level coincided with the locations of known function genes. Coincident QTL for a number of mailing‐quality traits on chromosome 7 suggests either the presence of a multi‐locus cluster of genes controlling components of malting quality or a regulatory gene or genes controlling the cascade of enzymatic processes that function during the malting process. Based on these results, simultaneous selection for malting quality and cold tolerance should be possible in this genetic background.
Response to selection for root dimension in a Mediterranean natural population of Lolium rigidum Gaud
Authors: Bullitta S. 
Published: April 2006

AbstractIn the Mediterranean environment, root systems are very important for water utilization. For this reason, the effects of selection for increased root dimensions upon root and shoot characteristics of a natural population of Lolium rigidum Gaud, were analysed. Two cycles of phenotypic recurrent selection were carried out on a population collected in Nurra (north‐western Sardinia, Italy). Plants derived after two cycles of selection, together with unselected plants, were grown hydroponically in a greenhouse. Data on root volume, longest root length, number of stems and leaves, leaf length, shoot and root dry weight were collected from the selected material and also from unselected material for use as a control. An analysis of variance was performed and correlation coefficients were calculated. The increased size of the root system did not have a negative effect on the above‐ground biomass and there was genetic variation for root traits in the ‘Nurra’ population. The improved population will be utilized for further breeding work to obtain L. rigidum varieties capable of withstanding dry periods during the vegetative phase.
Patterns and heritability of carboxylic acids and soluble sugars in fruits of apricot (Prunus armeniaca L.)
Authors: Bassi D. , Bartolozzi F. , Muzzi E. 
Published: April 2006

AbstractThe investigation of acid and sugar content in an array of apricot cultivars and progenies indicates the existence of marked variability. Citric acid varied from 0.17 to 1.20% and malic acid from 0.21 to 1.51% on fresh weight. Fructose varied from 0.27 to 1.60%, glucose from 0.90 to 3.13% and sucrose from 1.92 to 6.92%. The estimate of heritability was high for total and main sugars, reaching over 0.50%. Acids generally showed low coefficients, although those for citric (0.27) and malic (0.36) were good. With the exception of one progeny, all genotype/year comparisons were not significant, showing constant patterns for acid and sugars over the years regardless of the variability in absolute values. This means that the patterns of each genotype are under genetic control. The wide range of diversity in acid and sugar content in apricot germplasm and the independent heritability for most of these compounds make it possible to breed and select cultivars with improved flavour on the basis of superior phenotypes.
Use of gamma rays to induce mutants resistant to cocoa swollen shoot disease in Theobroma cacao L.
Authors: Adu‐Ampomah Y. , Owusu G. K. , Sackey S. , Padi B. , Abdul‐Karimu A. 
Published: April 2006

AbstractVegetative buds of three cocoa varieties, ‘Amelonado’ (P30), ‘Trinitario’ (K5) and ‘Upper Amazon’ (T85/799) were irradiated with 15, 20 and 25 Gy of γ‐rays, respectively, and budded on to rootstocks to generate MV1 shoots. The terminal buds of the shoots were removed to induce the formation of MV2 shoots, from which MV3 shoots were similarly derived. The MV3 plants were screened for resistance to the Cocoa Swollen Shoot Virus (CSSV) by patch‐graft inoculation of the root‐stocks. Only a few plants from each of the three cocoa varieties were found to be symptomless after indexing. These plants were multiplied by budding to the MV4 and MV5 stages and screened at each stage for CSSV resistance by inoculation using virus‐carrying mealybugs. At the MV5 stage, some plants still remained symptomless and this was confirmed with enzyme‐linked immunosorbent assay (ELISA). The study reveals that γ‐rays can be used to induce genetic variability for resistance to CSSV in cocoa, as well as for other traits such as chlorophyll deficiency.
Meiotic restitution mechanisms and 2n pollen formation in a Solanum tuberosum dihaploid and in dihaploid × wild species hybrids*
Authors: Conicella C. , Genualdo G. , Errico A. , Frusciante L. , Monti L. M. 
Published: April 2006

AbstractA Solatium tuberosum dihaploid that proved to be a 2n pollen producer, exhibited two types of meiotic abnormality involved in 2n pollen formation: premature cytokinesis at prophase II and parallel/tripolar spindles in meiosis II. For this reason such a dihaploid was preferentially used as a seed parent in crosses with the diploid species S. tarijense, S. sanctae‐rosae, and S. phureja. Diploid interspecific hybrids were evaluated for male fertility, for 2n pollen production and stability over three years and for meiotic nuclear restitution mechanisms. Pollen stainability ranged from 6 to 85% and 2n pollen from 5 to 35% among hybrids. The meiotic mechanism generating 2n pollen was that of spindle abnormality in meiosis II and consequent dyad/triad formation. High correlation was found between fused/parallel spindles and dyads.
Development of diploid and triploid interspecific hybrids between Lilium longiflorum and L. concolor by ovary slice culture
Authors: Fernández A. M. , Nakazaki T. , Tanisaka T. 
Published: April 2006

AbstractOvary slice culture, after cut‐style pollination, was used to develop interspecific hybrids between Lilium longiflorum and L. concolor. Reciprocal crosses between diploid cultivars (2n = 2x = 24) were carried out. On the days 30, 35, 40 and 45th after pollination (DAP), ovaries were sliced and cultured on a modified hormone‐free Murashige‐Skoog (M–S) medium without NH4NO3, supplemented with 6% sucrose, 50 mg/1 yeast extract and 0.25% gelrite at pH 6.3. For the L. longiflorum × L. concolor cross, ovule germination was found to be best at 30 DAP. After transfer to a M–S (half‐strength) medium supplemented with 1.5% sucrose and 0.25% gelrite at pH 5.8, diploid and triploid hybrid plants were established. In contrast, ovules from the L. concolor × L. longiflorum cross did not germinate. The hybridity of the plantlets obtained was verified by karyotype and isozyme analysis. The importance of the ovary slice culture technique as a tool to develop new hybrids between incompatible lilly plants is discussed.
Genetic resistance to root‐knot nematode (Meloidogyne javanica) in eggplant (Solanum melongena)
Authors: Boiteux L. S. , Charchar J. M. 
Published: April 2006

AbstractA germplasm collection of 39 eggplant Solanum melongena genotypes and one accession of S. torvum was evaluated for resistance to the root‐knot nematode (Meloidogyne javanica) by using controlled greenhouse tests. Different degrees of resistance to the disease caused by this nematode species were observed among the genotypes tested. Complete resistance (no nematode egg mass formation up to 7 weeks after inoculation) was detected in one accession belonging to domesticated S. melongena species. Good levels of incomplete resistance were also observed in some commercial eggplant genotypes. This is apparently the first report of a source of complete resistance to M. javanica within the S. melongena gene pool and our finding could greatly facilitate the incorporation of this trait into commercial eggplant cultivars. S. torvum, previously described as resistant to several root‐knot nematode species (including M. javanica, M. arenaria, and M. incognita) was also confirmed as a source of resistance to this Brazilian population of M. javanica. Therefore, S. torvum can be considered as one of the most promising sources of broad‐spectrum resistance genes against root‐knot nematodes. Broad‐spectrum resistance is of paramount importance for breeding programmes focused on the development of cultivars for tropical and subtropical areas of the world where multiple infestation of soils with distinct Meloidogyne species is a very common feature.