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731.
Two long primers of 19 (F17) and 20 (F13) nucleotides, respectively,were used in polymerase chain reactions to amplify DNA from differentcultivated barley accessions. These primers can distinguish closely relatedvarieties and, with a unique primer, all the barley accessions analysedshowed a characteristic fingerprint. Sixty per cent and 76% of thefragments generated using F13 and F17, respectively, were polymorphic.The genetic similarity values between accessions were estimated from F13and F17 data. The dendrogram and principal coordinate analysis performedwith F13 data revealed a clear separation of these varieties in accord withtheir pedigree relationships. 相似文献
732.
P. M. Franzone E. Y. Surez R. M. Solari E. A. Favret R. D. Rios A. H. Díaz Paleo 《Plant Breeding》1996,115(2):89-93
Three cultivars of wheat showing different levels of spontaneous karyotypic instability were studied regarding their stability in vitro for a number of characters, i.e. chromosome structure, gliadin pattern, glume and grain colour, awn type, chlorophyll pigmentation and plant morphology. The progenies of somaclones derived from immature embryos of both aneuploid and euploid plants were used in this study along with foundation seeds and a large number of their sexual progeny in order to discriminate between pre-existent variability and any novel variation induced by the in vitro culture. Only one translocation not described before and a new gliadin pattern were detected which could be ascribed to the effects of tissue culture, suggesting that this technique is not effective for inducing novel variation for breeding purposes in wheat. 相似文献
733.
Summary Results from a cooperative breeding programme with timothy for the northern areas of Scandinavia are presented. The main aim of the programme was to identify genotypes for synthetic populations that are high yielding, adapted over the whole area and stable over years. A polycross comprising 12 genotypes from each of five sites within the region was formed. The subsequent 60 half-sib families and four reference varieties were then compared under sward conditions at the same sites. The trials lasted for three years and results for total dry matter yields are presented.Significant differences in yield between lines were found. There were also significant two and three factor interactions between lines, sites and years. A new two-step procedure is presented to select the genotypes to make up a synthetic variety. Firstly, a superiority measure (Q-value) is used to select a group of genotypes that are high yielding and stable over sites and years. Secondly, the GxE part of the Q-value is split into two terms. One measures adaptation to predictable environmental conditions. The other one measures stability to unpredictable changes in the environment. A plot of these two measures provides a tool for discarding unstable or poorly adapted genotypes. The statistical properties of the selection parameters are discussed. 相似文献
734.
Ram C. Sharma G. Ortiz-Ferrara J. Crossa M. R. Bhatta M. A. Sufian J. Shoran A. K. Joshi R. Chand Gyanendra Singh R. Ortiz 《Euphytica》2007,157(3):457-464
Improving the level and stability of grain yield is the primary objective of wheat breeding programs in the Eastern Gangetic
Plains (EGP) of South Asia. A regional wheat trial, the Eastern Gangetic Plains Yield Trial (EGPYT), was initiated by CIMMYT
in collaboration with national wheat research programs in Bangladesh, Nepal, and India in 1999–2000 to identify wheat genotypes
with high and stable grain yield, disease resistance, and superior agronomic traits for the EGP region. A set of 21 wheat
experimental genotypes selected from a regional wheat screening nursery in South Asia, three improved widely grown cultivars
(Kanchan, PBW343 and Bhrikuti), and one long-term cultivar (Sonalika) were tested at 9–11 sites in six wheat growing seasons
(2000–2005) in the EGP. The 21 experimental genotypes were different in each year, whereas the four check cultivars were common.
In each year, one or more of the experimental genotypes showed high and stable grain yield and acceptable maturity, plant
height, and disease resistance compared to the check cultivars. Three improved cultivars have already been commercially released
in the region through EGPYT and many germplasm lines have been used in the breeding programs as parents. Identification of
wheat genotypes with high-grain yield in individual sites and high and stable yield across the EGP region underlines their
value for regional wheat breeding programs attempting to improve grain yield and agronomic performance. 相似文献
735.
Sexual plant reproduction is a complex process that involves a series of interactions between the male gametophyte and the
different cell types of the pistil. These interactions are believed to direct the pollen tube growth until its final target,
the embryo sac. Arabinogalactan proteins are complex proteoglycans that are believed to be involved in these processes. The
pistil is enriched in these highly glycosylated proteins and we provide results that show the selective presence of different
AGP epitopes at the surface of the cells or in the ECM of the tissues that correspond exactly to the pollen tube growth pathway
in Amaranthus hypochondriacus and Actinidia deliciosa. We also show that in Actinidia deliciosa, which is a dioecious plant
with the male flowers having rudimentary ovaries where fertilization does not occur, there is no presence at all of the epitopes
recognised by the monoclonal antibodies utilized in this study.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
736.
Eveline Teixeira Caixeta Aluízio Borém Samir de Azevedo Fagundes Silvia Niestche Everaldo Gonçalves de Barros Maurílio Alves Moreira 《Euphytica》2003,134(3):297-303
The existence of genetic variability for angular leaf spot (ALS) resistance in the common bean germplasm allows the development
of breeding lines resistant to this disease. The BAT 332 line is an important resistance source to common bean ALS. In this
work we determined the inheritance pattern and identified RAPD markers linked to a resistance gene present in BAT 332. Populations
F1, F2,BCs and BCr derived from crosses between BAT 332 and cultivar Rudá were used. Rudá is a commercial cultivar with carioca
type grains and susceptible to ALS. The resistance of BAT 332 to race 61.41 of the pathogen was confirmed. Segregation analysis
of the plants indicated that a single dominant gene confers resistance. For identification of RAPD markers linked to the resistance
gene, bulk segregant analysis (BSA) was used. Two RAPD markers,OPAA07950 and OPAO12950, linked in coupling phase at 5.10 and 5.83 cM of this gene, respectively, were identified. These molecular markers are important
for common bean breeders and geneticists as source of genetic information and for marker assisted selection in breeding programs.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
737.
Genetic relationships among 18 accessions, including 16 of Ananas and two of Pseudananas, were investigated using RAPD molecular markers. The procedure for DNA extraction was adapted from the method of Dellaporta
et al. (1983) where an incubation in proteinase K and a purification step were included. From the total of 148 markers scored,132
(89.2%) were polymorphic. The similarity matrix was used for cluster analysis. The phenogram developed from the RAPD bands
showed that for most of the cases, the accessions within a species grouped together. Nevertheless, a moderate infraspecific
genetic variation was observed. For example, DNA data grouped all A. comosus accessions with a mean similarity coefficient of 0.85. Comparable results were obtained with all other species investigated.
The highest genetic divergence was found withinA. lucidus where the mean similarity coefficient among accessions was0.75. A similar level of genetic polymorphism was observed among
species,therefore, a definition about which species were involved in the constitution of A. comosus genotypes was not possible. These results agree with the breeders standpoint suggesting that all Ananas species belong to the primary gene pool of pineapple.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
738.
Karim Sorkheh Behrouz Shiran T. M. Gradziel B. K. Epperson Pedro Martínez-Gómez E. Asadi 《Euphytica》2007,156(3):327-344
Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient method for producing DNA fingerprints and
molecular characterization. Our objectives were to: estimate genetic similarities (GS), marker indices, and polymorphic information
contents (PICs) for AFLP markers in almond cultivars; assess the genetic diversity of almond cultivars and wild species, using
GS estimated from AFLP fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression
and cultivar improvement. The genetic diversity of 45 almond cultivars from Iran, Europe, and America, were studied assaying
19 primer combinations. In addition, several agronomic traits were evaluated, including flowering and maturity times, self-incompatibility,
and kernel and fruit properties. Out of the 813 polymerase chain reaction fragments that were scored, 781 (96.23%) were polymorphic.
GS ranged from 0.5 to 0.96, marker indices ranged from 51.37 to 78.79, and PICs ranged from 0.56 to 0.86. Results allowed
the unique molecular identification of all assayed genotypes. However, the correlation between genetic similarity clustering
as based on AFLP and clustering for agronomic traits was low. Cluster analysis based on AFLP data clearly differentiated the
genotypes and wild species according to their origin and pedigree, whereas, cluster analysis based on agronomic data differentiated
according the pomological characterization. Our results showed the great genetic diversity of the almond cultivars and their
interest for almond breeding. 相似文献
739.
André M. Almeida Anabela B. Silva Susana S. Araújo Luís A. Cardoso Dulce M. Santos José M. Torné Jorge M. Silva Matthew J. Paul Pedro S. Fevereiro 《Euphytica》2007,154(1-2):113-126
We have previously obtained several lines of tobacco transformed with a trehalose-6-phosphate synthase gene of plant origin
(Arabidopsis thaliana), involved in the first step of the biosynthesis of trehalose, a known osmoprotectant. Two showed distinct intensity of expression:
high (B5H) and low (B1F). Such lines were analyzed for trehalose-6-phosphate content and the obtained results demonstrated
to be in accordance with the expression results. In order to study the responses of photosynthesis to water deficit of transgenic
lines in comparison to wild type (WT), three experiments were performed under different conditions: (1) Relative water (2)
Leaf gas exchange (3) Modulated Chlorophyll a Fluorescence. Different responses in RWC of plant lines to water withdrawal were detected, with transgenic line B5H indicating
less water loss after the water withdrawal period. Similar responses to water deficit regarding the leaf gas exchanges were
recorded for the three lines. When subjected to water deficit stress situations, higher F
v/F
m, ΦPSII and qP were detected for the transgenic lines. Under a SWC of 20% where higher values for such parameters were detected with
special relevance for the B5H line, indicating a possible higher ability to withstand severe drought stress and to resist
to prolonged periods without water than the B1F and WT lines. 相似文献
740.
2n Gamete formation in the genus Brachiaria (Poaceae: Paniceae) 总被引:1,自引:0,他引:1
Patrícia Helena Gallo Pamela Lonardoni Micheletti Kellen Regina Boldrini Claudicéia Risso-Pascotto Maria Suely Pagliarini Cacilda Borges do Valle 《Euphytica》2007,154(1-2):255-260
Microsporogenesis of several Brachiaria species of the Brazilian collection at Embrapa Beef Cattle has been analyzed in detail. This paper reports abnormal cytokinesis
in three accessions of three different species (Brachiaria humidicola, 2n = 4x = 36, Brachiaria decumbens, 2n = 4x = 36, and Brachiaria dura, 2n = 6x = 54). Chromosomes paired in bi-, tri-, and quadrivalents in these accessions, whereas chromosome segregation at meiosis
I was characterized by exclusion of laggards as micronuclei. In a high number of meiocytes, the first sign of cytokinesis
appeared only in metaphase II and did not divide the meiocyte into a dyad. Total absence of cytokinesis was also detected
among meiocytes in the second division. Since in both cases the two metaphase plates were very close, they favored the rejoining
of chromosome sets after anaphase II and formed a restitutional nucleus in telophase II. Second cytokinesis occurred after
telophase II in most meiocytes. Monads, dyads, and triads with n or 2n nuclei were observed among meiotic products. The 2n gametes observed correspond to the first division restitution (FDR). The number of affected cells in each accession was variable,
but the number of microspores with restitutional nucleus, including those scored in tetrads and the released ones, did not
exceed 9%. Although polyploidy is common in the genus Brachiaria, its origin is still unclear. Current results suggest that 2n gametes may have contributed to the evolutionary history of the genus. 相似文献