1,721,279 research outputs found
Parthenogenesis induction in diplosporic tetraploidized alfalfa.
No full textBecause gametophytic apomixis in alfalfa [lucerne] is strongly correlated with the occurrence of hybridity and poliploidy, bilateral sexual polyploidization (BSP) schemes were adopted for introgressing the diplosporic mutation of PG-F9 at the tetraploid level using unreduced pollen producers of M. coerulea. Tetraploidized F1 plants from BSP were then backcrossed with mutant PG-F9 (employed as unreduced egg donor) and the BC1 progenies screened for level of ploidy, occurrence of diplospory, genetic similarity with diploid parents, and fertility in controlled matings with tetraploid testers of M. sativa. Nine tetraploid BC1 plants out of 15 recovered showed a degree of diplospory ranging from 5.04 to 40.96%. In order to promote parthenogenesis in these mutants, named DTA (Diplosporic Tetraploidized Alfalfa), two methods were adopted: treatments with auxins and crosses after emasculation with M. coerulea. Four plants yielded an average of 5.7 seeds out of 47 flowers treated with NAA, whereas two plants produced an average of 5.6 seeds out of 46 flowers pollinated. These seeds were sown and DNA samples from each plant were analyzed with PCR-based molecular markers. To assess the genetic identity between progenies and the mother plants, two markers per linkage group of an already developed genetic map will be scored. The presence of all selected maternal markers in a single progeny plant will support that seeds were formed by apomixis. Results on the mode of reproduction of DTA plants and the possibility of assembling an apomictic system of seed production in alfalfa are reported and discussed
Digital dermatoglyphics in children with beta-thalassemic trait
No full textThe fingerprints of 162 children with Cooley's trait were analyzed. Statistically significant differences in thalassemic children in comparison with controls were observed especially with regard to fingerprint type frequency and their distribution on either sex
Fully automated assessment of left ventricular volumes and mass from cardiac magnetic resonance images
No full textQuantification of left ventricular (LV) size and function from cardiac magnetic resonance (CMR) images requires manual tracing of LV borders on multiple 2D slices, which is subjective, tedious and time-consuming experience. This paper presents a fully automated method for endocardial and epicardial boundaries detection for the assessment of LV volumes, ejection fraction (EF) and mass from CMR images. The segmentation procedure is based on a combined level set approach initialized by an automatically detected point inside the LV cavity. To validate the proposed technique, myocardial boundaries were manually traced on end-diastolic (ED) and end-systolic (ES) frames by an experienced cardiologist. Bland-Altman analysis and linear regression were used to validate LV volumes, EF and mass and similarity metrics were applied to assess the agreement between manually and automatically detected contours. We found minimal biases and narrow limits of agreement for LV volumes, EF and mass; Dice coefficient, Jaccard index and Hausdorff distance evaluated for 2D ED and ES endocardial and epicardial boundaries showed adequate overlapping. The proposed technique allows fast and accurate assessment of LV volumes, EF and mass as a basis for accurate quantification of LV size and function, and myocardial scar from CMR images
Mapping of AFLP and RAPD markers linked to apomeiosis in Medicago falcata and to parthenogenesis in Poa pratensis.
No full textL'osservazione citologica ed istologica come mezzo d'indagine nello studio dei sistemi riproduttivi.
No full textThe recent developement of stain-clearing techniques allowed an increase in the information concerning cytological mechanisms responsible for 2n egg formation. Using these methodologies, our research group has already characterized several diploid alfalfa mutants producing 2n eggs at high frequency. Moreover, it was verified that stain-clearing techniques can be efficiently applied also to the cytological analysis of microsporogenesis and therefore they will be useful for a quick cytological analysis of mutants producing both 2n pollen and 2n eggs. In the present paper, our results, together with the potential applications of stain-clearing techniques in advanced breeding programs based on the use of 2n gametes, are discussed
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