Hybrid breeding for biomass yield in winter triticale: II. Combining ability and hybrid prediction

Accurate hybrid prediction and knowledge about the relative contribution of general (GCA) and specific combining ability (SCA) are of utmost importance for efficient hybrid breeding. We therefore evaluated 91 triticale single-cross hybrids in field trials at seven environments for plant height, heading time, fresh biomass, dry matter content and dry biomass. Fresh and dry biomass showed the highest proportion (23%) of variance due to SCA. Prediction accuracies based on GCA were slightly higher than based on mid-parent values. Utilizing parental kinship information yielded the highest prediction accuracies when both parental lines have been tested in other hybrid combinations, but still moderate-to-low prediction accuracies for two untested parents. Thus, hybrid prediction for biomass traits in triticale is currently promising based on mid-parent values as emphasized by our simulation study, but can be expected to shift to GCA-based prediction with an increasing importance of GCA due to selection in hybrid breeding. Moreover, the performance of potential hybrids between newly developed lines can be predicted with moderate accuracy using genomic relationship information.     

Microbiological studies on bacterial spectra of milk samples from healthy udder quarters and from those with increased cell counts and/or conductivity values]

The germ levels of 2,182 milk samples obtained from udder quarters with subclinical mastitis were compared to milk sampled from 2,061 udder quarters with physiological cell counts or conductivity values. Three cattle herds were involved in the test programme. No germ growth was established from 9.5 per cent of all samples taken from udder quarters with increased cell counts and conductivities and from 4.1 per cent of those samples taken from intact udder quarters. Samples taken from udder quarters with subclinical mastitis exhibited the following rises in bacteria, as compared to samples from intact quarters: staphylococci by 3.1 per cent, staphylocci in germ mixtures by 3.0 per cent, CAMP-positive streptococci by 2.2 per cent, alpha-haemolytic CAMP-negative streptococci by 0.8 per cent, anhaemolytic streptococci in germ mixtures by 0.4 per cent, beta-haemolytic streptococci by 0.5 per cent, and Pseudomonas aeruginosa by 1.4 per cent. Other germ species and mixtures exhibited declining trends along with growing subclinical affection of udder quarters. All findings so far obtained in the presence of subclinical mastitis are likely to suggest that 11.4 per cent of detected bacteria were of pathogenicity to udders. However, attempts to localise those 11.4 per cent were unsuccessful, since no significant difference could be calculated by comparison of intact with affected udder quarters. Reference is made in the discussion to primary and secondary germ levels of milk samples and their relevance to the problem and its elucidation.     

Comparison of postmortal changes in the ultrastructure of the masseter muscle and the longissimus dorsi muscle in pigs with PSE-meat]

Samples of the two muscles were taken from 8 Landrace fattened pigs, affected with pale, soft exudative meat, during stunning and 15, 30, 45 and 60 minutes after death; also 2, 3, 6, 12, 24 and 48 hours after slaughter, with storage at 20 degrees C for the first six hours and 2-5 degrees C subsequently. Considerable changes were found during the first hour after death, or even in samples taken during stunning, in longissimus dorsi samples. These consisted of destruction of mitochondria and sarcoplasmic reticulum, breakdown of cell membranes, liberation of clumps of fibre protein, disappearance of glycogen, rigor and destruction of capillaries. Such changes would account for the features of pale, soft exudative meat such as water loss, brief rigor, pale colour, deficiency of energy-rich phosphates. By contrast, in the masseter muscles of the same animal these changes did not occur until later, or were in port absent. In both muscle the breakdown of fibres took place by destruction of the "I" bands and the "Z" strips, and this process also commenced in longissimus dorsi before masseter.     

Preliminary study of plasma vascular endothelial growth factor (VEGF) during low- and high-dose radiation therapy of dogs with spontaneous tumors

High plasma vascular endothelial growth factor (VEGF) concentrations are associated with radiation resistance and poor prognosis. After an exposure to ionizing radiation in cell culture an early phase and a late phase of increased VEGF have been documented. The activation was dependent on the radiation dose. Therefore, the purpose of this study was to measure baseline plasma VEGF and changes in VEGF over the course of fractionated radiation therapy in dogs with spontaneous tumors. Dogs with tumors had a significantly higher pretreatment plasma VEGF than did dogs without tumors. Immediately after irradiation no increased plasma VEGF was observed. Over the course of radiation therapy there was an increased plasma VEGF in dogs treated with low doses per fraction/high total dose, whereas plasma VEGF remained stable in dogs irradiated with high doses per fraction/low total dose. The regulatory mechanisms are very complex, and therefore the value of plasma VEGF measurements as an indirect marker of angiogenesis induced by radiotherapy is limited.     

Two reported cytotypes of the emergent orchid model species <Emphasis Type="Italic">Erycina pusilla</Emphasis> are two different species

Each species is characterized by a specific set of chromosomes, which is described as the chromosome portrait or karyotype. In general, such a karyotype is the same for all individuals in the population. An exception to that rule has recently been found in the orchid Erycina pusilla, which has been reported to have two cytotypes with chromosome numbers of 2n = 10 and 2n = 12. Here, we examined the karyotypes of the two cytotypes and found differences in arm ratios and heterochromatin patterns as well as in the presence of satellite chromosomes and in the number and location of rDNA and telomeric repeat sites. These differences are extensive and would have required multiple chromosome rearrangements to generate the differences between the two karyotypes. We also found that F1 hybrids between the parents with the two different chromosome numbers resulted in sterile offspring, in accordance with our previous findings. The combination of hybrid sterility and extensively rearranged chromosomes supports the hypothesis that these two reported cytotypes are, in fact, two different species.