Orobanche species and population discrimination using intersimple sequence repeat (ISSR)

Summary Orobanche species are commonly identified using morphological characteristics. In many cases, the distinction of closely related species is difficult, and a molecular tool is more suitable to differentiate them. In this study, genomic polymorphism between morphologically distinct species was investigated through amplification by polymerase chain reaction (PCR) of intersimple sequence repeat (ISSR) regions. Five primers were used to study genetic variation in the morphologically distinct species O. hederae and O. amethystea, as well as the closely related species O. cernua and O. cumana. For the first two species, all the primers detected genetic polymorphism. Anchored primers allowed the identification of more specific molecular markers than non‐anchored tri‐ and tetranucleotide primers. Genetic polymorphism was investigated among three O. hederae populations using the two types of primer. One non‐anchored and two anchored primers detected intraspecific variation, which was not correlated with the geographical location of those populations. The primer (GATA)₄ detected polymorphism between five specimens each of O. cernua and O. cumana species collected from different countries, permitting these two closely related species to be clearly differentiated. This study demonstrated that ISSR markers can be highly reliable for precise identification of Orobanche species.     

Effect of tetracosactid on post partum cyclicity in cows after induction of parturition with PGF2 alpha

Parturition and retention of fetal membranes were induced with PGF2 alpha in 3 primiparous dairy cows. Starting on day 12 post partum (PP) the cows were treated with 500 micrograms i.m. of ACTH-analogue (tetracosactid) every 6 h for 6 times. Changes in plasma concentrations of cortisol, progesterone and 15-ketodihydro-PGF2 alpha were evaluated immediately after treatment. The effects on the resumption of ovarian activity were evaluated by clinical and ultrasound examinations and by progesterone and 15-ketodihydro-PGF2 alpha analyses for 56 days after parturition. Treatment was able to induce a statistically significant (p < 0.01) similar increase in cortisol and progesterone after both the 1st and the 6th injections, in all cows. No changes in 15-ketodihydro-PGF2 alpha concentrations were seen after any of the injections of ACTH-analogue. The first corpus luteum (CL) was seen on day 18 PP (cow A), and 28 (cow B) and in both cases it was followed by a normal ovarian cyclicity. No CL was observed during the whole period of study in cow C. Progesterone profiles confirmed these clinical and ultrasonographic findings. The steroid output, especially progesterone, induced by the ACTH-analogue might be a stimulus for the onset of ovarian cyclicity, since 2 of the 3 animals ovulated earlier than expected. These findings point to the fact that interference with the stress system might have a positive effect on ovarian cyclicity. The different pattern of response does however demand further studies.     

Anoplocephala perfoliata infestation and colics in horses

Veterinary Research Communications -     

Karyotype and C-banding pattern of mitotic chromosomes in alfalfa, Medicago sativa L.

Numerous cytogenetic studies have been performed on alfalfa (Medicago sativa L. 2n= 4x= 32), but only a few have examined the somatic chromosomes. Because the major factor limiting the study of somatic chromosomes of M. sativa is their rather uniform morphology, characterization was attempted using the C-banding technique instead of the traditional Feulgen method. Chromosome morphology and position of the heterochromatic bands resulted in satisfactory characterization of the chromosomes and provided further evidence of the autotetraploid origin of the species. It was possible to identify the homologous chromosomes and arrange them into eight groups of four. The ideogram of the basic genome of eight chromosomes was constructed. The impact of these results on cytogenetic studies and breeding research in alfalfa is discussed.     

Fingerprinting of alfalfa meiotic mutants using RAPD markers

Summary A calendar of female sporogenesis and gametogenesis was made for both apomictic tetraploid (2n=4x=36) Brachiaria brizantha and Brachiaria decumbens and their apomictic F₁ hybrids with sexual tetraploid (2n=4x=36) Brachiaria ruziziensis. Microgametogenesis was used as a reference. Apospory was facultative in both species and hybrids. Environmental conditions had variable effects on the level of apomixis according to each genotype. Ratios of segregation into sexuals and apomicts in the interspecific hybrids suggest an oligogenic determinism with dominant apomixis in the genus Brachiaria. Highly apomictic and partially male fertile hybrids were identified and will be used in an improvement program to transfer genes for apomixis into the sexual species B. ruziziensis.     

Evaluation of an Italian germplasm collection of Festuca arundinacea Schreb. through a multivariate analysis

Summary Forty-eight accessions of tall fescue (Festuca arundinacea Schreb.), collected from Northern to Southern Italy, were analyzed using both univariate and multivariate analysis applied to a set of 12 quantitative traits. Four principal components were found to explain 77% of the total variation in the dependence structure. Productivity characters together with heading time and dimensions of flag leaf appeared to be the major sources of diversity among tall fescue populations. On the basis of the 4 principal components similar populations were clustered according to minimal distance analysis. Seven clusters were identified. The results of cluster analysis confirmed the presence of a remarkable diversity within the germplasm collection and explained why results of a univariate analysis of variance did not reveal significant differences among groups of accessions collected in Northern, Central and Southern Italy. The multivariate approach seemed to point out a problem of genetic erosion of the local germplasm in the Po Valley (Northern Italy) and, on the whole, appeared to be a valid system for tall fescue germplasm evaluation.Research supported by C.N.R., Italy, special grant I.P.R.A., Subject 1.5.1., paper n. 1146.     

Seed Yield Selection in Medicago sativa L. and Correlated Responses Affecting Dry Matter Yield

Open pollinated (OP) progenies from 72 plants, selected for seed yield within a population of the Italian synthetic variety ‘Adriana’, were evaluated in 1983–1986 under dense stand conditions, both for dry matter yield (DMY) of the 1st cut and seed yield (SY) of the 2nd regrowth. Analysis of variance of the results showed the presense of significant differences in SY potential among entries, with average SY over the years of open pollinated (OP) progenies ranging between 32.1 gm^-3. In contrast, the OP progenies were not significantly different in DMY, averaging between 0.61 kg m^-2 and 0.77 kg m^-2. The results show the possibility of selecting for SY without a negative response affecting DMY in lucerne. Furthermore, the most interesting materials appeared to be characterized both by high average SY and SY stability over the year.     

Phenotypic recurrent selection for 2n pollen and 2n egg production in diploid alfalfa

Corrigendum

Phenotypic recurrent selection for 2n pollen and 2n egg production in diploid alfalfa     

Molecular characterization of emmer (Triticum dicoccon Schrank) Italian landraces

Emmer (Triticum dicoccon Schrank,2n = 4x = 28) is a hulled wheatspecies [more] widely spread in the Mediterranean basin. In Italy it survives as acrop in a few marginal areas and peculiar ecological niches in different regionsof central and southern Italy. A renewed interest has occurred during the lastdecade toward local varieties belonging to this species. As a matter of fact,local varieties have the highest genetic variation and adaptation to the naturaland anthropological environment from where they originated. Results on thegenetic diversity within and relationships among 11 Italian local varieties ofemmer as assessed with 17 RAPD marker loci are here reported. The proportion ofthe among-local variety genetic diversity was as high as 48% (G_ST =0.479). Thus, about 52% of the total variation was within population. Localvarieties of emmer proved to be formed by a variable number of lines geneticallydistinguishable from each other, and the vast majority of individuals overpopulations proved to be different multilocus genotypes. Landraces of emmer fromcentral and southern Italy showed distinctive molecular traits. In particular,local varieties classified as «Central Italy» types were characterized by a common set of RAPD marker alleles and proved to bedistinguishable from both the «Southern Italy» and the«Garfagnana» accessions. The overall results confirm the highvariability that can be found within landrace populations, underlining thevalues of landraces as an irreplaceable bank of genetically diversified andhighly co-adapted genotypes. Information for an appropriate insitu conservation and management of this valuable source of emmergermplasm is discussed.     

Long-term effect of toltrazuril on growth performances of dairy heifers and beef calves exposed to natural Eimeria zuernii and Eimeria bovis infections

The long-term effects of a toltrazuril treatment against natural Eimeria bovis and/or Eimeria zuernii infections were investigated in comparison with diclazuril and untreated controls on two dairy (Italian Friesian breed) and two beef (Chianina breed) farms. At each trial site, 30 calves were allocated into three groups of 10 calves each: T (treated with toltrazuril), D (treated with diclazuril) and C (left untreated). For 40 weeks post-treatment, the calves were weighed and examined clinically and parasitologically. The oocyst counts as well as the number of scour days were significantly lower in the T group than in the D and C groups. Final bodyweights and body condition scores of the T group exceeded those of groups C and D. The results confirmed that toltrazuril was highly efficacious, safe and provided productive benefits in dairy and beef calves.