Assessment of electrodynamic spraying as an alternative to ultra-low-volume spraying in western Tanzania

The introduction of ULV (ultra-low-volume) spraying to cotton farmers in western Tanzania in the early 1970s was a major contribution to the cotton industry as the control of cotton insect pests was made easier and possible in many areas. However, spray drift and increased cost of ULV insecticides and batteries have been major constraints to ULV spraying in recent years, so a spraying technique allowing greater efficacy and reduced costs is needed. Trials to assess the potential of electrodynamic spraying as an alternative to ULV spraying started in western Tanzania in 1979. The present study assessed swath width, dosage rates and farmer's reaction to the ‘Electrodyn’® hand-held sprayer as compared with the hand-held spinning-disc sprayer (Micron ULVA), currently used by farmers in Tanzania, in order to identify the optimum combination package to be recommended to farmers. Cypermethrin ED applied at a dosage rate of 15·8–31·6 g a.i./ha by the Electrodyn sprayer over a swath width of 3·0 m gave good control of H. armigera. Yields of seed cotton were comparable to those with ULV cypermethrin applied at a dosage rate of 62·5 g a.i./ha. The spray volume was reduced from 2·5 l/ha applied with the spinning disc to 0·35 l/ha with electrodynamic spraying. Reduced drift, dosage of active ingredient and volume rates, and reduction in the number of batteries needed in a season, were among the major advantages of electrodynamic spraying over ULV spraying in western Tanzania.     

Resistance against <Emphasis Type="Italic">Fusarium graminearum</Emphasis> and the relationship to β-glucan content in barley grains

Fusarium head blight (FHB) caused by Fusarium graminearum (FG) is a destructive disease impacting barley worldwide. The disease reduces the grain yield and contaminates grains with mycotoxins, such as the trichothecene deoxynivalenol (DON). Although the infection mainly affects the grain yield, little is known about its impact on grain structural and biochemical properties. Yet, such information is instrumental to characterize the facets of resistance in the grains. After artificial inoculation of six barley cultivars with FG in a 2 years field test, different levels of symptoms on spikes, of colonisation of grains and of DON content were observed. The infections caused a reduction in grain weight and an average decrease of 10% of the β-glucan content in grains, indicating alterations of grain filling, composition and structure. According to our results, we postulate the presence of two distinct resistance mechanisms in the grain, tolerance to grain filling despite infection as well as the inhibition of mycotoxin accumulation. Differently to wheat, in barley, type IV resistance (tolerance of the grain to infection) is directly linked with type III resistance (resistance against kernel infection). The resistance against toxin accumulation (named type V resistance in wheat) appeared to be independent to all other resistance types. Generally, the resistance was significantly influenced by the environment and by genotype x environment interactions explaining the generally weak stability of resistance in barley. Interestingly, a significant and inverse relationship between DON contamination and β-glucan content in grains suggests that high β-glucan content in grains contributes to type V resistance.     

Deficit in attachment behavior in mice lacking the mu-opioid receptor gene

Endogenous opioid binding to micro receptors is hypothesized to mediate natural rewards and has been proposed to be the basis of infant attachment behavior. Here, we report that micro-opioid receptor knockout mouse pups emit fewer ultrasonic vocalizations when removed from their mothers but not when exposed to cold or male mice odors. Moreover these knockout pups do not show a preference toward their mothers' cues and do not show ultrasonic calls potentiation after brief maternal exposure. Results from this study may indicate a molecular mechanism for diseases characterized by deficits in attachment behavior, such as autism or reactive attachment disorder.     

Generating genetic variation in narrow‐leafed lupin (Lupinus angustifolius L.) for plant architecture by ethyl methanesulfonate mutagenesis

Narrow‐leafed lupin (NLL) is a source of protein and fibre with exceptional functional properties useful for a variety of purposes. In adapted NLL germplasm selected for low alkaloid contents, the genetic base is narrow, thus limiting fast breeding progress. In an EMS‐based mutagenesis programme, we have treated 40,000 seeds of cv. ‘Boruta’ and obtained a variety of phenotypic mutant lines expressing novel growth types with altered plant height and/or branching. In 3‐year field trials at two locations, three of these lines exhibited significantly improved grain yield components compared to the cv. ‘Boruta’. Growth types of these promising lines were shown to be inherited in a monogenic recessive manner and should, thus, be easily fixable by breeding.     

Structure, chemical composition, and xylanase degradation of external layers isolated from developing wheat grain

The external layers of wheat grain were investigated during maturation with respect to chemical and structural features and xylanase degradability. Cytochemical changes were observed in the isolated peripheral tissues of the wheat grain at four defined stages following anthesis. Marked chemical changes were highlighted at 11 days after anthesis, for which protein and lipid contents varied weakly. The profile of esterified ferulic acid showed large variation in the maturing peripheral layers of grain in contrast to the deposition of ferulate dimers, p-coumaric and sinapic acids. Lignin was monitored at the latest stages of ripening, which corresponds to the cessation of reserve accumulation in the grain. Arabinoxylans (AX) reached a maximum at 20 days and did not display any significant change in arabinosyl substitution proportion until ripeness. When submitted to xylanase, all outer layers were similarly altered in the proportion of soluble AX except for the peripheral tissues of the 11-day-aged wheat grain that had very little AX. Aleurone and nucellar layers were mostly degraded, whereas pericarp stayed intact at all stages of maturation. This degradation pattern was connected with the preferential immunolocalization of xylanase in aleurone and nucellar layers irrespective of the developmental stages. Further chemical examination of the enzyme-digested peripheral tissues of the grain supports the facts that ferulic ester is not a limiting factor in enzyme efficiency. Arabinose branching, ferulic dimers, and ether-linked monomers that are deposited early in the external layers would have more relevance to the in situ degradability of AX.     

Resistance to Meloidogyne chitwoodi,M. fallax and M. hapla in wild tuber-bearing Solanum spp.

Summary Over 5000 plants from 64 tuber-bearing wild Solanum spp. have been individually screened for resistance to Meloidogyne chitwoodi, M. fallax and M. hapla. Seedlings were analyzed by means of counting number of egg masses and resistance was verified by retesting low-scoring plants using stem cuttings. Resistance to both M. chitwoodi and M. fallax was observed in S. bulbocastanum, S. cardiophyllum, S. brachistotrichum, S. fendleri and S. hougasii. Only in S. chacoense and to a lesser extent in S. stoloniferum and S. gourlayi differential results between M. chitwoodi and M. fallax were observed. Resistance to M. hapla was found in S. bulbocastanum, S. brachistotrichum, S. cardiophyllum, S. arnezii, S. chacoense, S. tarijense, S. boliviense, S. gourlayi, S. microdontum, S. sparsipilum, S. spegazzinii, S. sucrense, S. acaule and S. hougasii. The occurrence of resistance in wild Solanum species in relation to their taxonomic status and the implications for introgression of resistance into S. tuberosum are discussed.     

Site-specific field resistance of grapevine to <Emphasis Type="Italic">Plasmopara viticola</Emphasis> correlates to altered gene expression and was not modulated by the application of organic amendments

The influence of site on resistance of grapevine (cv. Chasselas) to Plasmopara viticola was evaluated. Grapevine leaves from three vineyards in the region of Lake Neuchatel (Switzerland) were tested for their susceptibility to P. viticola in the lab in five successive years (2004–2008), and the expression levels of four selected defence-related genes (Glucanase, Lipoxygenase 9, 9-cis epoxycarotenoid dioxygenase, Stilbene synthase) were studied in 1 year. In all 5 years of examination, differences between sites were substantial. In four out of 5 years, plants from site Hauvernier were much less susceptible to P. viticola than plants from site Auvernier. In another year, differences were less pronounced but still significant for one leaf age. Susceptibility of plants from a third site (Concise) varied from year to year. Differences in the genetic background were excluded by microsatellite analysis. Differences in susceptibility were mirrored in the constitutive expression pattern of four defence-related genes, with samples from the Hauterive site clearly separated from samples of the other two sites in redundancy analysis. Furthermore, it was evaluated whether site-specific resistance can be modulated by agronomic practices such as the application of organic amendments. In two commercial vineyards (cv. Pinot noir), soils had either not (control) or yearly (compost) been amended with a compost for the last 9 years. Leaves from plants grown in any of the two treatments did not differ in their susceptibility to P. viticola in both years of examination. Additionally, under controlled conditions, none of 19 different composts amended to the substrate of grapevine seedlings or cuttings affected their susceptibility to P. viticola, but 8 out of 19 composts reduced severity in the control bioassay Arabidopsis thaliana—Hyaloperonospora arabidopsidis, indicating that a modulation of site-specific susceptibility of grapevine plants by organic amendments is at the very least, difficult.