bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simple technique for the identification of embryo‐carrying seeds from wheat × maize crosses prior to dissection
Authors: Bains N. S. , Mangat G. S. , Singh K. , Nanda G. S. 
Published: April 2006

AbstractEmbryo rescue is an important step in the wheat x maize system of induced haploidy in wheat. On average, only one‐third of the seeds carry embryos, but they all have to be dissected because no morphological distinction is available to distinguish between seeds with and without embryos. We here report a simple technique in which immature seeds from wheat × maize crosses are placed on a transparent surface and illuminated from above. The free‐floating embryo, settled at the bottom of the seed, can be seen from below or in an image reflected on a plane mirror. Using this technique 97.8% of the embryo‐containing seeds could be detected prior to dissection. The technique will be useful in reducing the time and labour involved in embryo culture, thereby scaling up haploid production.
Cytogenetics of the ‘glandless‐seed and glanded‐plant’ trait from Gossypium sturtianum Willis introgressed into upland cotton (Gossypium hirsutum L.)
Authors: Bi I. Vroh , Baudoin J. P. , Mergeai G. 
Published: April 2006

AbstractIn order to introgress the ‘glandless‐seed and glanded‐plant’ trait from Gossypium sturtianum Willis (2n= 2x= 26, C1 genome) into the cultivated upland cotton Gossypium hirsutum L. (2n= Ax= 52 (AD), genome), two trispecific hybrids have been created using either Gossypium thurberi Torado (2n= 2x= 26, D1 genome) or Gossypium raimondii Ulbrich (2n= 2x= 26, D5 genome) as bridge species. The cross of both trispecific hybrids by G. hirsutum produced the first backcross progenies (BCl). Cytogenetic analysis showed that the trispecific hybrids had 52 chromosomes, their chromosome configurations at metaphase I (Ml) being 15.071 + 15.3411 + 0.93III + 0.69IV + 0.26VI in G. thurberi×G. sturtianum×G. hirsutum (TSH) and 14.421 + 17.0311 + 0.82III + 0.15IV + 0.07VI in G. hirsutum × G. raimondii ×. G. sturtianum (HRS), respectively. Among six BCl plants analysed, the only plant expressing the ‘glandless‐seed and glanded‐plant’ trait had 52 chromosomes and a meiotic configuration of 5.261 + 20.61II + 0.69III + 0.77IV at MI. Pollen fertility was 2.90% in TSH, 8.97% in HRS, and ranged from 0% to 40.28% in the BCl progenies. The introgressed BCl plant is perennial in growth habit. It can be used in breeding programmes aiming at the introgression of the ‘glandless‐seed and glanded‐plant’ trait into a cultivar of upland cotton.
Forage yield potential of alfalfa plants of varying crown size from old stands
Authors: Kimbeng C. A. , Bingham E. T. 
Published: April 2006

AbstractAlfalfa (lucerne) plants can persist from one growing season to the next because of their perennial crowns. Plants with large crowns often are selected for breeding purposes. The objective of this study was to determine the forage yield potential of plants with a full range of crown sizes sampled from old stands. This was accomplished by field evaluation of clones and S1 progenies derived from plants of different crown sizes obtained from a 1 m2 of 5‐year‐old stands of cultivars ‘Agate’ and ‘Magnum III’. Significant differences (P < 0.05) in dry forage yield (DFY) were found among entries in both tests. However, there was no consistent trend in DEY with respect to the crown size of the parental plants. Although the crown of space‐planted clones dug after 16 months showed a strong association (r > 0.7, P < 0.01) with DFY, the crown size of these clones was poorly correlated with the crown size of their parental plants. These results suggest that selections based on crown size from older stands may not lead to an improvement in either crown size or forage yield. Crown health will remain an important selection criterion when plants are sampled from old stands; crown size, however, may not be as important.
Influence of pollination modes on yield components in strawberry (Fragaria×ananassa Duch.)
Authors: ŻEbrowska J. 
Published: April 2006

AbstractThe effects of self, wind and open pollination on yield components were investigated in five strawberry genotypes, the cultivars ‘Dukat’, ‘Paula’, ‘Redgauntlet’, ‘Senga Sengana’ and the breeding clone B‐302. Investigations were also conducted to look for additional plant characteristics associated with strawberry yield components after various modes of pollination. Such characteristics would facilitate the indirect selection of highly self‐compatible strawberry genotypes. The greatest effect of self pollination was observed in B‐302 and ‘Redgauntlet’, while the least effect of autogamy was shown m Paula. Conversely, the last cultivar revealed the greatest effect of entomophily, whereas the greatest effect of wind pollination was observed in ‘Dukat’. Relationships between yield components and some flower and pollen characteristics after various pollinations indicated that the degree of self compatibility in strawberry can be predicted from the pollen grain length and the pollen size index. Genotypes producing long pollen grains with large size indices exhibited the greatest effect of autogamy. Anther size, especially length. Which correlated more strongly with yield components than width, could also be used as an index of autogamy in the strawberry. Pollen yield per flower an self compatibility.
Occurrence of microsatellites in spinach sequences from computer databases and development of polymorphic SSR markers
Authors: Groben R. , Wricke G. 
Published: April 2006

AbstractMicrosatellites are valuable tools as molecular markers in plant breeding. To establish genetic linkage maps or for population studies, information about the occurrence and usability of microsatellite markers in different species is necessary. Sequences of spinach Spinacia oleracea from computer databases were therefore searched for the presence of microsatellites. Sixty simple sequence repeats were found in 237 spinach sequences with a total of 349.4 kb DNA. After removing duplicated sequences, 50 different microsatellites with various motifs remained. Differences between nuclear and chloroplast DNA were not in the number of microsatellites but in their type and length. Chloroplast sequences from spinach contain only short strings of A and AT repeats, whereas nuclear sequences show a wider variety of motifs.Flanking primers for polymerase chain reaction (PCR) analysis were designed for 13 of these microsatellites and tested with two different varieties of spinach. Twelve primer pairs gave amplification products and seven of these showed polymorphisms in the variety ‘Wiremona’ but only one in the variety ‘Monatol’. These markers may be used for linkage analysis or population studies in spinach.
Chromosomal localization of genes for carotenoid pigments using addition lines of Hordeum chilense in wheat
Authors: Alvarez J. B. , Martín L. M. , Martín A. 
Published: April 2006

Abstract×Tritordeum sp. (Ascherson et Graebner) is the amphiploid obtained after chromosome doubling of hybrids between Hordeum chilense (Roem. et Schult.) and diploid, tetraploid or hexaploid wheats. Tritordeums have consistently higher carotenoid pigment contents than durum or bread wheat. Two distinct H. chilense accessions (used for the synthesis of tritordeum) were analysed for this trait. The chromosomal localization of the genes coding the ability of H. chilense to increase the carotene content of wheat were carried out using two sets of wheat‐ H. chilense addition lines. The a arm of chromosome 7Hch is proposed to be responsible for the high carotene content in tritordeum. The implication of this finding in wheat breeding is discussed.
Identification of the series‐specific random amplified polymorphic DNA markers of Viola species
Authors: Oh B. J. , Ko M. K. , Lee C. H. 
Published: April 2006

AbstractAlthough many Viola species are grown as ornamentals, no information on molecular markers is available for the classification and breeding of Viola. Random amplified polymorphic DNA (RAPD) analysis was applied to identify series‐specific molecular markers from the series Pinnatae, Chinensis, and Variegatae of Viola species in the subsection Patellares. We report eight RAPD markers which can be used to distinguish three different series of Viola species based on morphological characters. The eight RAPD markers we identified could be useful to classify Viola species and to assist the hybrid breeding of new varieties.
Molecular mapping of QTL for southwestern corn borer resistance, plant height and flowering in tropical maize
Authors: Khairallah M. M. , Bohn M. , Jiang C. , Deutsch J. A. , Jewell D. C. , Mihm J. A. , Melchinger A. E. , González‐De‐León D. , Hoisington D. A. 
Published: April 2006

AbstractDevelopment of multiple insect resistance in tropical maize represents a major effort of the maize breeding programme at CIMMYT. Resistance to the southwestern corn borer (SWCB) is polygenically controlled with primarily additive gene action. Our main objective was to identify quantitative trait loci (QTL) involved in resistance to SWCB. Other objectives were to detect QTL in the same population for plant height, female flowering, and the anthesis‐silking interval (ASI). A population of 472 F2 individuals derived from a cross between the susceptible line Ki3 and the resistant inbred CML139, was restriction fragment length polymorphism (RFLP) genotyped using 110 maize probes. F3 families were rated for leaf‐feeding damage after artificial infestation at one location in three consecutive years. Height and flowering were measured in protected trials in two locations. QTL analyses were conducted using joint composite interval mapping. Seven QTL on chromosomes 3, 5, 6, 8, and 9 explained 30% of the phenotypic variance (σ2p) for SWCB damage. Most QTL alleles conferring resistance were contributed from CML139. QTL showed dominance, partial dominance and additive gene action. Eleven QTL dispersed across the genome were determined to affect plant height and explained 43% of σ2p. Four of these were in close proximity to loci with qualitative effects on plant height. Thirteen QTL (50% of sigma;2p) were identified for days to female flowering and nine (30% of σ2p) for ASI. Our results, along with those from other mapping studies at CIMMYT, are allowing us to formulate marker‐assisted selection schemes to complement the breeding efforts for such complex traits as borer resistance.
Single and combined effects of colchicine, L‐proline and post‐inoculation low temperature on anther culture of wheat, Triticum aestivum L.
Authors: Redha A. , Attia T. , Büter B. , Stamp P. , Schmid J. E. 
Published: April 2006

AbstractThis investigation was undertaken to study the effects of colchicine, L‐proline and a post‐inoculation cold temperature of 14°C for 7 days, either as a single or as combined treatments, on the parameters of anther culture of the DH83Z118.32 wheat genotype. Results indicate that the addition of 100 mg/1 colchicine to the induction medium for a period of 3 days and at an incubation temperature of 28°C yielded the highest success index. This treatment, although it significantly reduced embryogenesis, improved embryoid quality so that not only the total regeneration, but also the percentage of green plantlets increased significantly, In addition, it raised the percentage of doubled haploids and, consequently, led to a significantly better final success index. Combining the colchicine treatment with a reduced post‐inoculation temperature did not intensify its beneficial effect, although a treatment of reduced temperature alone was superior to normal temperature (28°C) for most parameters studied. The beneficial effects of adding L‐proline (200 mg/1) to the induction medium, combined with a low temperature (10°C for 4 days) treatment, were diminished when this treatment was combined with a colchicine treatment.
Effect of selection and temperature stress on the production of 2n gametes in Lotus tenuis
Authors: Negri V. , Lemmi G. 
Published: April 2006

AbstractFive Lotus tenuis genotypes showing 2n pollen production greater than 5% and producing 4x progenies in 4x(male sterile Lotus corniculatus) × 2x crosses were found in different natural populations. Meiotic analyses of these plants showed some second metaphases with disoriented spindles, i.e. parallel and tripolar spindles which resulted in diads and triads, respectively. Because useful genes for winter growth and resistance to powdery mildew from L. tenuis can be introgressed into L. corniculatus via 2n gametes, a programme of selection was started to increase the occurrence of 2n gamete production in L. tenuis. Controlled crosses were performed between genotypes producing 2n gametes and the progenies were checked for 2n pollen production and meiotic aberration, following the same methodologies as used for the parental plants. Although in some progeny plants the frequency of 2n gamete production increased remarkably, the overall progeny level of 2n gamete production remained unchanged. This suggested that different genes for meiotic aberration exist in natural populations and/or differential seed‐setting ability exists between genotypes. Diallel crosses between selected genotypes confinned this hypothesis. Evaluation of 2n pollen production of clones grown under different temperature regimes (warm vs. temperate) showed that, in L. tenuis, the effects of genotype, temperature and genotype × temperature interaction are significant. In particular, high temperature increases the level of 2n gamete production in L. tenuis.
Variation in seed proteins from mutagen‐treated cultivars and selected lines of Vigna unguiculata L. Walp
Authors: Osanyinpeju A. O. , Odeigah P. G. C. 
Published: April 2006

AbstractThe storage protein profiles of the seeds of two IITA cowpea cultivars (‘IT84E–124’ and ‘Vita 7’) exposed to three mutagens—sodium azide (NaN3), ethyl methane sulphonate (EMS) and 60Co gamma rays—and those of 18 selected M3 lines were investigated by sodium dodecyl sulphate (SDS)‐polyacrylamide gel electrophoresis (PAGE). The total seed protein, globulin and albumin fractions showed differences in number and intensity of subunit bands, but the least differences were found in the albumin fraction. Both high and low molecular weight bands were observed, the highest being 94.5 kDa and the lowest 12.0 kDa.‘Vita T showed less variability compared with ‘IT84E–124’, as indicated by the relative similarity indices (S.I.) of the two cultivars. The lowest S.I. of 0.200 was found among ‘IT84E–124’ lines while the lowest S.I. among ‘Vita T lines was 0.4706. A number of lines with particular traits were found to be characterized by the presence of specific polypeptide bands. This study demonstrates that induced mutation could create additional variability to supplement existing germplasm and that SDS‐PAGE is a useful tool for discriminating and estimating genetic similarities among selections.
Breeding for Sclerotinia resistance in sunflower: A modified screening test and assessment of genetic variation in current germplasm
Authors: Degener J. , Melchinger A. E. , Gumber R. K. , Hahn V. 
Published: April 2006

Abstract Sclerotinia sclerotiorum (Lib.) de Bary is one of the most devastating pathogens of sunflower (Helianthus annuus), causing yield losses up to 100%. This study was conducted to (1) screen sunflower lines for their reaction to Sclerotinia using artificial infection by a modified leaf test, and (2) identify the most suitable trait for screening against Sclerotinia resistance. A set of 85 inbred lines was screened in three environments by infecting the leaves with mycelium and covering them with plastic bags containing water. Susceptibility was assessed by leaf lesion, petiole score, stem rating, stem lesion and diseased stems. The test proved to be effective and practicable, with an infection rate of up to 99%. All scoring traits were strongly correlated with each other and effective in differentiating among susceptible and resistant lines. Although petiole score had the highest heritability, its association with leaf length hampers its utilization as a scoring trait. Stem lesion was a good predictor of mid‐stalk rot and can be recommended as a reliable trait for screening sunflower lines against Sclerotinia based on its high heritability estimate (h2= 0.59) and close correlations with other traits measured after artificial and natural infection.
Genes for race‐specific resistance against blackleg disease in Brassica napus L.
Authors: Ansan‐Melayah D. , Balesdent M. H. , Delourme R. , Pilet M. L. , Tanguy X. , Renard M. , Rouxel T. 
Published: April 2006

AbstractSpecificity of interaction at the cotyledon stage was recently demonstrated between the blackleg pathogen, Leptosphaeria maculans, and Brassica napus. Three pathogenicity groups were distinguished, PG2 avirulent towards ‘Quinta’ and ‘Glacier’, PG3 avirulent towards ‘Quinta’, and PG4 virulent on the two cultivars. The genetic control of the interactions was investigated on both the pathogen and the plant. Tetrad analysis was performed following PG3 × PG4 and PG2 × PG4 crosses.‘Quinta’ and ‘Glacier’ were crossed with the susceptible winter oilseed rape cultivar ‘Score’. The analysis of F1, F2 and testcross populations suggested that the incompatible interaction between ‘Quinta’ and PG3 isolates is conditioned by the presence of the dominant single resistance allele Rlml in ‘Quinta’ and the matching avirulence gene AvrLml in L. maculans. Race‐specific resistance of ‘Glacier’ to PG2 isolates was conditioned by the matching gene pair Rlm2/AvrLm2. Finally, the data suggest that two avirulence genes matching two dominant loci control the ‘Quinta’‐PG2 interaction. The consequences of the occurrence of race‐specific resistance in B. napus are discussed with respect to future breeding for blackleg resistance.
Selection for non‐branching in castor, Ricinus communis L.
Authors: Baldanzi M. , Pugliesi C. 
Published: April 2006

AbstractA 5‐year selection programme was conducted to obtain an unbranched type of castor plant suitable for efficient mechanical harvesting. Each population (Sn) consisted of several progenies obtained from the selfed main raceme of unbranched plants selected in the previous generation (Sn‐1). After self‐fertilization of all individuals, selection was conducted in the autumn, at the end of the cycle, so as to have fully developed plants. Unbranched plants were counted in each generation. Comparisons between populations showed significant differences owing to increased recovery of the selected phenotype over the generations. The final population could be useful as a source for the development of improved cultivars in future breeding programmes.
Efficient production of doubled haploid wheat plants by in vitro treatment of microspores with trifluralin or APM
Authors: Hansen N. J. P. , Andersen S. B. 
Published: April 2006

AbstractIsolated microspore cultures from two doubled haploid (DH) lines of wheat, Triticum aestivum L., were used to develop an in vitro chromosome‐doubling protocol. During the initial 24 h or 48 h of culture the microspores were treated with either of the two antimicrotubule herbicides trifluralin or amiprophos‐methyl (APM) in concentrations ranging from 0.1 μM to 10μM. Untreated control cultures yielded 209 embryos per 100000 microspores, which is the equivalent of one spike. Among the regenerated plantlets 67% were green, and 15% of the flowering plants were spontaneously chromosome doubled. Treatments with both the herbicides had a significant effect on chromosome doubling, measured as the percentage of fertile regenerants. With the best combination of treatment duration (48 h) and herbicide concentration (10/μM) the percentage of fertile plants among regenerants could be increased up to 74% with APM and up to 65% with trifluralin. The largest numbers of DH plants per spike could be obtained with herbicide concentrations at 1–3 μM. Treatments with either herbicide at these concentrations resulted in an estimated average between the two genotypes of 27 DH plants per 100 000 microspores. These results demonstrate the high potential of APM and trifluralin as chromosome‐doubling agents in isolated microspore cultures. The in vitro treatment integrated into tissue culture procedures will constitute an efficient method for chromosome doubling in future wheat breeding
Variation in resistance to the grain aphid, Sitobion avenae (Sternorhynca: Aphididae), among diploid wheat genotypes: Multivariate analysis of agronomic data
Authors: Di Pietro J. P. , Caillaud C. M. , Chaubet B. , Pierre J. S. , Trottet M. 
Published: April 2006

AbstractA collection of 87 ancient wheat genotypes, 67 Triticum monococcum, 13 Triticum boeoticum, seven Triticum urartu and one cultivar of the modern wheat Triticum aestivum (variety ‘Arminda’) were evaluated for resistance to the cereal aphid Sitobion avenae, the main damaging aphid pest on winter wheat in Europe. The intrinsic rate of natural increase (rm), which is regarded as a good estimate of the fitness of an aphid population, was used as an indicator for the level of plant resistance. Differentiation of the 88 plant genotypes into four distinct groups was achieved with a cluster analysis of the rm values. The modern wheat ‘Arminda’ was more susceptible than any of the ancient wheat genotypes tested (rm= 0.24, i.e. the aphid population doubled every 2.6 days). A second group of 19 plants ranged from relatively susceptible to moderately resistant (0.17 < rm < 0.21). Fifty–one plants were allocated to a third group and classified as resistant (0.09 < rm < 0.16). The last group contained 17 genotypes with a high level of resistance where aphid fitness was greatly reduced (0.02 < rm < 0.09, i.e. the aphid population doubled every 11.4 days or 7.7 days, respectively). Clustering of the accessions into the different phenetic groups did not follow the geographical origin of the wheat genotypes or the species to which they belong. These results show that ancient diploid wheats, all characterized by the genome A, present considerable interest for plant breeding for resistance to S. avenae in modern wheat. The potential use of these strong and partial sources of resistance for introduction of a stable and durable form of resistance to S. avenae in wheat is discussed.
Variation in Ethiopian barley landrace populations for resistance to barley leaf scald and netblotch
Authors: Yitbarek S. , Berhane L. , Fikadu A. , Van Leur J. A. G. , Grando S. , Ceccarelli S. 
Published: April 2006

AbstractOne‐hundred and eighty landrace populations and six‐hundred single‐head plants selected from 60 promising populations were evaluated for resistance to scald and netblotch at three locations in Ethiopia. Each accession was tested with and without the application of 50% of the recommended rate of fertilizer at planting. Plants were rated for disease attack two to four times during the season. Both diseases were enhanced by the application of fertilizer and were more severe at the testing sites of Holetta and Bekoji than at Sheno. The difference in disease resistance among and within populations was considerable. Moreover, populations from Arsi and Bale tend to be more susceptible to scald but more resistant to netblotch than populations from other regions. Populations collected from higher altitudes were more resistant to scald, but susceptible to netblotch, than were populations from lower altitudes. The paper illustrates approaches to the identification of valuable genotypes from landrace populations that can be incorporated into a breeding programme for the development of improved varieties with resistance to the principal diseases of barley in Ethiopia.