Genetic evaluation and selection index in tetraploid Brachiaria ruziziensis

Half‐sib progenies of congo signal grass (Brachiaria ruziziensis Germain & Evrard, syn.: B. eminii, Urochloa ruziziensis) were analysed using a mixed model methodology. The objective was to estimate genetic and phenotypic parameters, predict individual genetic values, estimate correlations between characters associated with biomass production and forage nutritive value and use this information to determine the economic weights to compare three multiplicative selection indices. Individual narrow‐sense heritabilities corrected for inbreeding varied from 0.14 to 0.91 for characters associated with biomass production and from 0.04 a 0.24 for nutritional value characters. The correlations among characters associated with annual biomass production were of high magnitude. In contrast, biomass production characters were negatively correlated with crude protein, acid detergent fibre and lignin. Total dry matter yield, crude protein and regrowth ability were weighted separately in evaluations during wet and dry season or annually in selection indices. Index that considered characters annually resulted in better distribution of forage production along the year than indices that separated wet and dry season production.     

Saline water and MSW compost: Effects on yield of maize crop and soil responses

A field experiment was carried out in Southern Italy from 2007 to 2010 adopting a two-year rotation of tomato and maize. In this paper, the results of maize cultivation were reported, with the aim to investigate the effects of different water qualities and fertilizers on yield and soil properties. The following treatments were compared: mineral nitrogen (N) fertilizer and irrigation with fresh water (FWF); mineral N fertilizer and irrigation with saline water (SWF); Municipal Solid Waste (MSW) compost and irrigation with fresh water (FWC); MSW compost and irrigation with saline water (SWC). These treatments were compared with an unfertilized control and irrigation with fresh-water (FW0) and an unfertilized control and irrigation with saline water (SW0). At harvest, yield, grain moisture content, dry matter, grain protein, starch, fat content and soil characteristics were determined. The treatments with compost increased the average grain yield of the 11% compared to mineral fertilizer treatments. Furthermore, the grain yield in SWC increased of the 19% respect to average of SWF and SW0, indicating that MSW compost applied as amendment mitigated the adversely effects of saline water. Compost application significantly increased the Total Organic Carbon (TOC). In particular, the FWC and SWC treatments showed an average increase of the 25% compared to the mean TOC value of FWF and SWF. Moreover, at the end of the experiment, electrical conductivity decreased in SWC treatment respect to the SWF (?21%).     

Weak effects of habitat type on susceptibility to invasive freshwater species: an Italian case study

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A multi-scale approach to facultative paedomorphosis of European newts (Salamandridae) in the Montenegrin karst: Distribution pattern, environmental variables, and conservation

Facultative paedomorphosis, a process in which newt larvae can opt for reproduction before or after metamorphosis, is geographically heterogeneous. Despite numerous ecological studies and recent evidence of declines in paedomorphic populations, however, no attempt to model environmental variables that explain the presence of paedomorphs has been made at a multi-scale level. Our aim was to fill this gap in studying three newt species (Lissotriton vulgaris, Mesotriton alpestris, and Triturus macedonicus) of the Montenegrin karst as model species. To this end, we used multivariate analysis on three scales of habitat: the breeding pond, the land use and the climatologic features. Results show that the study area is both an important hotspot for paedomorphosis and where intraspecific diversity is quickly disappearing (20-47% extirpation) because of fish introductions. Other habitat variables (water permanency, pH or the habitat origin) were shown to act on paedomorphosis but not consistently across species, confirming complexity of the evolutionary and ecological processes. This study appeals for more long-term and detailed landscape studies of polyphenisms, a neglected but promising topic, to better understand and protect alternative modes of development. Particularly, measures should be taken to identify hotspots of intraspecific diversity at a global scale and stop fish introductions before we reach a point of no-return.     

Protective effect of the AT137RQ and ARQK176 PrP alleles against classical scrapie in Sarda breed sheep

The susceptibility of sheep to scrapie is under the control of the host’s prion protein (PrP) gene and is also influenced by the strain of the agent. PrP polymorphisms at codons 136 (A/V), 154 (R/H) and 171 (Q/R/H) are the main determinants of susceptibility/resistance of sheep to classical scrapie. They are combined in four main variants of the wild-type ARQ allele: VRQ, AHQ, ARH and ARR. Breeding programmes have been undertaken on this basis in the European Union and the USA to increase the frequency of the resistant ARR allele in sheep populations. Herein, we report the results of a multi-flock study showing the protective effect of polymorphisms other than those at codons 136, 154 and 171 in Sarda breed sheep. All ARQ/ARQ affected sheep (n = 154) and 378 negative ARQ/ARQ controls from four scrapie outbreaks were submitted to sequencing of the PrP gene. The distribution of variations other than those at the standard three codons, between scrapie cases and negative controls, was statistically different in all flocks. In particular, the AT₁₃₇RQ and ARQK₁₇₆ alleles showed a clear protective effect. This is the first study demonstrating a protective influence of alleles other than ARR under field conditions. If further investigations in other sheep breeds and with other scrapie sources confirm these findings, the availability of various protective alleles in breeding programmes of sheep for scrapie resistance could be useful in breeds with a low frequency of the ARR allele and would allow maintaining a wider variability of the PrP gene.     

A combination of Lactobacillus buchneri and Pediococcus pentosaceus extended the aerobic stability of conventional and brown midrib mutants–corn hybrids ensiled at low dry matter concentrations by causing a major shift in their bacterial and fungal community

We evaluated the effects of applying a combination inoculant to four corn hybrids harvested at high moisture on their nutritive value and microbial populations. The treatment design was the factorial combination of corn hybrids ensiled with (INO) and without (CON) inoculant. The hybrids were TMF2R737 (MCN), F2F817 (MBR), P2089YHR (PCN), and PI144XR (PBR), ensiled at dry matter (DM) concentrations of 30.5%, 26.3%, 31.1%, and 31.5%, respectively; MBR and PBR were brown midrib mutants (BMR). The inoculant contained Lactobacillus buchneri and Pediococcus pentosaceus (4 × 10⁵ and 1 × 10⁵ cfu/g of fresh corn). The experiment had a complete randomized design with treatments replicated six times. Corn was treated or not with inoculant, packed into 7.6 L bucket silos, and stored for 100 d. At d 0, the relative abundance (RA, %) of Enterobacteriaceae was lower in PBR vs. the other hybrids [51.3 vs. x¯ = (average of) 58.4] and in the case of fungi, incertae sedis (i.s.) Tremellales and Mucoraceae were more and less abundant, respectively, in conventional hybrids vs. BMRs (x¯= 25.8 vs. x¯ = 13.9 and x¯ = 3.64 vs. x¯ = 7.52; P < 0.04). After ensiling, INO had higher LAB (9.3 vs. 7.1 log cfu/g of fresh corn) and acetic acid (3.44% vs. 1.32% of DM) and lower yeast (3.1 vs. 4.6) and molds (1.5 vs. 3.0), and also extended the aerobic stability (582 vs. 111 h) but decreased DM recovery (95.6% vs. 97.4%) vs. CON (P < 0.02). Inoculation reduced bacterial phylogenetic diversity (6.75 vs. 14.4) but increased fungal observed taxonomical units (46 vs. 20) vs. CON (P < 0.01). Also, a higher relative abundance (RA) for Lactobacillaceae (99.2% vs. 75.7%) and lower for Enterobacteriaceae (0.28 vs. 9.93) was observed due to inoculation (P < 0.001). For fungi, INO had a lower RA compared to CON for Monascaceae (12.6 vs. 44.7) and increased i.s. Tremellales (8.0 vs. 1.2) and i.s. Saccharomycetales (6.4% vs. 0.3%; P < 0.006). Inoculation changed the diverse bacterial community found in the phyllosphere across hybrids to a taxonomically uneven one dominated by Lactobacillaceae. In the case of fungi, INO application increased the fungal diversity at d 100 mainly by reducing the dominance of Monascaceae vs. CON. In conclusion, the INO treatment overwhelmed the disparate microbial populations found across BMR and conventional hybrids ensiled at low DM concentrations and ensured a significant concentration of acetic acid that modified fungal populations and in turn extended the aerobic stability of all hybrids.