Temperature related instability of a naturally induced cytoplasmic male sterility in industrial chicory (Cichorium intybus L.)

Natural alloplasmic cytoplasmic male sterile (CMS) clones of industrial chicory were obtained after crossing wild chicory with selected breeding lines. We investigated the CMS stability of 10 clones in various environmental growing conditions. CMS was stable under cool growing conditions in most of them. Fertility restoration, based on pollen production scores, was observed in all clones after a period of hot temperatures. The early flower bud stage was sensitive, resulting in fertile flowers 12–17 days after exposure to high temperatures. Experiments under controlled growing conditions at 15°C demonstrated that a heat shock of 2 days at 25 or 30°C was sufficient to restore fertility. Sterile flowers were formed when plants were again grown at lower temperatures. Significant differences between individual clones were observed, indicating the potential of genetic selection to obtain stable CMS parent lines.     

The effect of weight loss on lameness in obese dogs with osteoarthritis

This paper describes the effect of weight loss on lameness in obese dogs with osteoarthritis (OA). Fourteen obese client-owned dogs with clinical and radiographic signs of OA participated in an open prospective clinical trial. After a screening visit and a visit for collection of baseline data, the dogs were fed a restricted-calorie diet over a study period of 16 weeks that incorporated six follow-up visits. At each visit, body weight and pelvic circumference were measured and severity of lameness was assessed using a numeric rating scale (NRS), a visual analogue scale (VAS) and kinetic gait analysis. This is the first study to assess both subjectively and objectively, the effect of weight loss alone on lameness in obese dogs with OA. The results indicate that body weight reduction causes a significant decrease in lameness from a weight loss of 6.10% onwards. Kinetic gait analysis supported the results from a body weight reduction of 8.85% onwards. These results confirm that weight loss should be presented as an important treatment modality to owners of obese dogs with OA and that noticeable improvement may be seen after modest weight loss in the region of 6.10 – 8.85% body weight.     

Tracing of 2n egg occurrence in perennial ryegrass (Lolium perenne L.) using interploidy crosses

Several genotypes of Lolium perenne (2n = 2x = 14) were screenedfor the production of 2n eggs. In each cross a diploid genotype, used asfemale parent, was pollinated with a tetraploid genotype. All interploidycrosses were made in isolation cages. Flow cytometrical analysis of theprogeny of 154 diploid plants revealed 28 tetraploid descendants. Theseoffspring plants were harvested on 15 different diploid mother plants.Amplified Fragment Length Polymorphism (AFLP) markers were used tocheck the parenthood of these tetraploids. Two seedlings died, theremaining plants could, after AFLP fingerprinting, be identified as meiotictetraploids. The results obtained allowed to conclude that the tetraploidprogeny plants harvested on 15 diploid mother plants were the result ofthe fertilisation of an unreduced egg by a reduced pollen grain of thetetraploid plant.     

Susceptibility of European cultivars of Italian and perennial ryegrass to crown and stem rust

A set of 15 Italian (Lolium multiflorum), three hybrid (L. boucheanum) and 33 perennial ryegrass (L. perenne) cultivars were evaluated for their rust susceptibility in the field. The cultivars were grown in 2001, 2004 and 2007 at 29, 32 and 27 European sites, respectively. Rust incidence was scored during different growth cycles using a scale from one (no rust) to nine (susceptible). Crown rust (Puccinia coronata f. sp. lolii) was the most frequently observed rust species on Italian, hybrid and perennial ryegrass during all three experimental years. There was a highly significant difference in mean crown rust scores among Italian and perennial ryegrass cultivars, respectively, in each of the 3 years. The ranking of the cultivars was very consistent across the different sites within each year (with some exceptions), despite a significant interaction of cultivar response with sites. Moreover, the rank order correlations of mean cultivar rust scores were highly significant (r > 0.9) between the years. Stem rust (P. graminis f. sp. graminicola) occurred almost exclusively on perennial ryegrass. The cultivars showed significant variation in stem rust susceptibility. Rank order correlations of mean cultivar stem rust scores were mostly significant between sites within each year and highly significant between the years. The ranking of perennial ryegrass cultivars was different depending on whether crown or stem rust was scored. However, the rank order correlation between the mean disease scores of the cultivars for the two pathogens was low but still significant. At a particular site the assessment of crown or stem rust was in most cases very consistent over the period of experimentation. Therefore there was no evidence that rust resistance of an individual cultivar was overcome by the rust pathogen at a particular site over the 7 years of experimentation.     

Response of Italian ryegrass (Lolium multiflorum Lam.) to coffee waste application on a humid tropical sandy soil

A greenhouse experiment was conducted to study the effect of coffee waste (CW) application on growth and mineral nutrition of Italian ryegrass in a tropical Arenosol. Dry CW was applied at three rates (5, 10, 20 t/ha) and thoroughly mixed with topsoil (0–25 cm), placed in pots and seeded with Italian ryegrass (Lolium multiflorum Lam.) according to a completely randomized design with six replicates. The application of CW greatly stimulated uptake of Ca, Mg, K, N and P, resulting in a significantly increased dry matter (DM) production over three consecutive cropping cycles. DM increases of at least 52, 87 and 81% compared with the unamended controls were obtained for the first, second and third cuts, respectively. Soil analysis after cultivation found that all CW‐amended soils still contained available macronutrients (Ca, Mg, K, N), which could produce residual effects in subsequent crops. Furthermore, CW application increased soil pH owing to its liming effect. This brought about an increase in cation exchange capacity with substantial reduction in phytotoxic Al and a decrease in availability of a number of metals (Cu, Zn, Mn and Fe) and significantly reduced their uptake by ryegrass. The study reveals a high potential of CW to improve the fertility of sandy soils in the humid tropics.     

Brominated phenols as auxin-like molecules

2,6-Dibromophenol (DBP) was reported as an auxin-like molecule using molecular quantum similarity measures. In this study, the auxin activity of this molecule and its chlorinated homologue is further determined using a bacterial biosensor: the auxin-inducible ipdC promoter of Azospirillum brasilense. We were able to demonstrate that DBP can induce gene expression, but to a lesser extent than the auxin indole-3-acetic acid (IAA) and that DBP is not an antagonist for the IAA signalling pathway. To investigate the role of the bromine groups, the molecule 2,6-dichlorophenol (DCP) was also tested for gene expression induction. However, no induction could be observed. In a second part, DBP and other molecules were modelled in the auxin-binding pocket of the plant auxin receptor TIR1 to evaluate theoretical binding energies. Both DBP and its chlorinated homologue DCP are not strong ligands compared to other known auxins such as IAA. The importance of a carboxylated side chain for optimal binding (and probably auxin activity) was demonstrated.