Genetic architecture of adult plant resistance to leaf rust in a wheat association mapping panel

Leaf rust caused by Puccina triticina is one of the most destructive fungal diseases of wheat (Triticum aestivum). Adult plant resistance (APR) is an effective strategy to achieve long‐term protection from the disease. In this study, findings are reported from a genome‐wide association study (GWAS) using a panel of 96 wheat cultivars genotyped with 874 Diversity Arrays Technology (DArT) markers and tested for adult leaf rust response in six field trials. A total of 13 quantitative trait loci (QTL) conferring APR to leaf rust were identified on chromosome arms 1BL, 1DS, 2AS, 2BL, 2DS, 3BS, 3BL, 4AL, 6BS (two), 7DS, 5BL/7BS and 6AL/6BS. Of these, seven QTLs mapped close to known resistance genes and QTLs, while the remaining six are novel and can be used as additional sources of resistance. Accessions with a greater number of combined QTLs for APR showed lower levels of disease severity, demonstrating additive and significant pyramiding effects. All QTLs had stable main effects and they did not exhibit a significant interaction with the experiments. These findings could help to achieve adequate levels of durable resistance through marker‐assisted selection and pyramiding resistance QTLs in local germplasm.     

Cyclic variation and solar forcing of Holocene climate in the Alaskan subarctic

High-resolution analyses of lake sediment from southwestern Alaska reveal cyclic variations in climate and ecosystems during the Holocene. These variations occurred with periodicities similar to those of solar activity and appear to be coherent with time series of the cosmogenic nuclides 14C and 10Be as well as North Atlantic drift ice. Our results imply that small variations in solar irradiance induced pronounced cyclic changes in northern high-latitude environments. They also provide evidence that centennial-scale shifts in the Holocene climate were similar between the subpolar regions of the North Atlantic and North Pacific, possibly because of Sun-ocean-climate linkages.     

How long should we measure? An exploration of factors controlling the inter-annual variation of catchment sediment yield

Purpose  

Although it is well-known that catchment suspended sediment yields (SY; tons per square kilometre per year) can vary significantly from year to year, little information exists on the magnitude and factors controlling this variability. This is crucial to assess the reliability of average SY values for a given measuring period (MP) and is of great geomorphic significance. This paper aims to bridge this research gap.     

Diagnostic de la rage sur culture cellulaire Comparaison des resultats de l'inoculation au neuroblastome murin et de l'inoculation a la souris

Mouse inoculation test (MIT) is a highly sensitive test for rabies diagnosis but slow and expensive. To detect rabies virus an in vitro technique using Neuro 2a cell culture (CC) was compared with MIT in two laboratories.

In one laboratory, CC appeared to be on the whole more sensitive than MIT, nevertheless MIT was the only one to detect some positive samples. In the other laboratory, MIT was more sensitive. These results justify the use of CC for epidemiological diagnosis but emphasize the interest of MIT (the reference technique) for special cases.     

Economic Feasibility and Risk Analysis of Australian Red Claw Crayfish Cherax quadricarinatus Aquaculture in the Southeastern United States

Australian red claw crayfish Cherar guudricurinutus are receiving increased attention from aqua-culturists, but have not been extensively investigated in terms of economic feasibility. In this study, research data from small pond experiments were combined with cost and return data to evaluate prospects for commercial production (50 ha scale) in the southeastern United States. Production data were derived from density experiments involving three initial stocking rates: "low" (l/m²), "medium" (3/m²) and "high" (5/m²). Experiments were conducted in nine 0.02 ha earthen ponds.
Risk analysis was used to simulate the range of potential outcomes that might be faced by producers. Results indicate that economic potential is most sensitive to the cost of juveniles, the percentage of the harvest biomass in the larger size classes, the price these classes receive, and the length of the growing season.     

Breed and trait preferences of Sheko cattle keepers in southwestern Ethiopia

Like their smallholder subsistence counterparts in developing countries, breed and trait preferences of Sheko cattle keepers have broad perspectives. Our study has documented breed and trait preferences of Sheko cattle keepers in southwestern Ethiopia—the natural breeding tract of Sheko cattle. Our results showed that due to their multifunctionality, cattle are the most preferred livestock species. Overall, farmers showed slightly more preference to local Zebus over Sheko breed. This is due to voracious feeding behavior of Sheko cattle, which make them less preferable in the face of worsening feed shortage, and due to aggressive temperament of Sheko cattle. This is despite Sheko's outperforming potential over local Zebus in their milk production, draft power, and hardiness. At trait level, overall milk production was consistently reported as the most preferred trait followed by fertility and traction. This trait preference rank has matched with the reported frequency count ranks for Sheko cattle use. However, breed preference rank has not matched with reported trait preference ranks because Sheko excels local Zebus in all the three most preferred traits, but it was ranked second. Therefore, to minimize these conflicting interests, breed management plans for Sheko cattle should target on strategies that help to solve feed shortage problem and to improve feeding practices, and on selection of less aggressive Sheko cattle. Therefore, these strategies should be considered in line with Sheko cattle conservation and genetic improvement programs.     

Controlling pests of tropical legumes; current recommendations and future strategies

Legumes have evolved effective defences against many pests by accumulating high levels of poisonous or indigestible compounds, pubescence and vigorous growth. These defences are greatly reduced in many cultivars of cowpea and common bean, which are susceptible to a succession of pest complexes. Stem pests and defoliators may kill seedlings but well-established plants tolerate heavy insect damage to leaves, flowers and green pods before pod or grain yields are reduced; virus vectors and root-knot nematode may be of greater importance. Generally, pod-borers, pod-sucking bugs and seed beetles are the main key pests. Control programmes are based on post-flowering treatments with broad spectrum insecticides. Battery-powered, controlled-droplet application machines are ousting knapsack sprayers in small-scale farming and competing with tractors and aircraft in larger units; subsistence cropping is still predominant and most legume crops remain unsprayed. Consequently, current emphasis is placed on developing cultivars with high yield potential and multiple pest and disease resistance. Insect infestations are lower in most other major legume crops largely due to pubescence (e.g. soybean, blackgram, greengram), fruiting in the dry season (e.g. pigeonpea, chickpea) or geocarpy (e.g. groundnut). Future entomological research will presumably concentrate on assessing the status of pests on resistant cultivars and introducing integrated control methods for the key pests.     

Bilateral renal agenesis in an alpaca cria

A 3-day-old male alpaca cria was presented for lack of vigor and failure to urinate since birth. Based on the history, laboratory data, ultrasonographs, surgical findings, and postmortem examination, the cria was diagnosed with bilateral renal agenesis and hypoplastic bladder, a congenital condition rarely seen in veterinary medicine.