A classification of the NORIN 10 and Tom Thumb dwarfing genes in British,Mexican, Indian and other hexaploid bread wheat varieties

Summary The two semi-dwarfing genes Rht1 and Rht2 from Norin 10 have now been incorporated in successful varieties in use in most major wheat growing areas. The more potent dwarfing gene, Rht3, from Tom Thumb has been used in a limited way.These genes may be identified and classified by assessing the associated character of GA-insensitivity in the progeny from test crosses.This paper describes these classifications in the CIMMYT, Mexican, PBI, Cambridge and Indian breeding programmes and for a number of other international varieties.     

Introgression and stabilization oferwinia tuber soft rot resistance into potato after somatic hybridization ofsolanum tuberosum ands. brevidens

Resistance to potato tuber soft rot caused byErwinia carotovora was transferred fromSolanum brevidens to the cultivated potato over the course of four backcross generations originating from a somatic hybrid. Soft rot reactions were determined via a tuber plug inoculation method developed during the course of these experiments. Soft rot resistance was highest in the somatic hybrid (only ca. 20% of tubers and plugs showed evidence of severe rotting) and lowest among progeny of control potato x potato crosses (ca. 80% of tuber plugs showed severe rot). Backcross generations involving somatic hybrids were intermediate in their reaction, and resistance stabilized to about 60% of tuber plugs showing severe rot in the BC₂ through the BC₄. Reciprocal crosses showed no difference in the inheritance of soft rot resistance, indicating that neitherS. brevidens norS. tuberosum donor cytoplasm had a significant effect on the expression of resistance. Crosses between BC₃ siblings where noS. brevidens genetic markers were detected but resistance was segregating demonstrated a dosage effect for soft rot resistance. We conclude that introgression of soft rot resistance has occurred and that at least one locus responsible for resistance inS. brevidens now resides in theS. tuberosum genome.     

Rice spikelet rot disease in China - 1. Characterization of fungi associated with the disease

Rice spikelet rot disease (SRD) is an emerging disease of rice panicle in China, which affects both rice yield and grain quality. Four fungal pathogens were isolated from diseased rice grains. Morphological observation, biological testing and molecular characterization led to identify these fungi as Fusarium proliferatum, Bipolaris australiensis, Curvularia lunata and Alternaria tenuis. The four fungi can grow from 10 °C to 40 °C, and from pH 5 to pH 10. The most suitable temperature range is 25 °C-30 °C, however the optimal pH for sporulation of these fungi varies greatly. The four fungi can grow on media supplemented with different carbon and nitrogen sources. These differences in carbon and nitrogen requirements suggest differences in trophism, and have large effects on hyphal growth and spore production. The results suggest that rice SRD is caused by various fungi with diverse physiological characteristics.     

Combination of Trabectedin and Gemcitabine for Advanced Soft Tissue Sarcomas: Results of a Phase I Dose Escalating Trial of the German Interdisciplinary Sarcoma Group (GISG)

Background: Evaluation of the potential efficacy and safety of combination therapies for advanced soft tissue sarcomas (STS) has increased substantially after approval of trabectedin and pazopanib. Trabectedin’s introduction in Europe in 2007 depended mainly on its activity in so-called L-sarcomas (liposarcoma and leiomyosarcoma); combination of trabectedin with other chemotherapies used in STS seems of particular interest. Methods: We initiated within the German Interdisciplinary Sarcoma Group (GISG) a phase I dose escalating trial evaluating the combination of trabectedin and gemcitabine in patients with advanced and/or metastatic L-sarcomas (GISG-02; ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01426633","term_id":"NCT01426633"}}NCT01426633). Patients were treated with increasing doses of trabectedin and gemcitabine. The primary endpoint was to determine the maximum tolerated dose. Results: Five patients were included in the study. Two patients were treated on dose level 1 comprising trabectedin 0.9 mg/m² on day 1 and gemcitabine 700 mg/m² on days 1 + 8, every 3 weeks. Due to dose-limiting toxicity (DLT) in both patients (elevated transaminases and thrombocytopenia), an additional three patients were treated on dose level −1 with trabectedin 0.7 mg/m² plus gemcitabine 700 mg/m². Of these three patients, two demonstrated another DLT; therefore, the trial was stopped and none of the dose levels could be recommended for phase II testing. Conclusion: The GISG-02 phase I study was stopped with the conclusion that the combination of gemcitabine and trabectedin is generally not recommended for the treatment of patients with advanced and/or metastatic leiomyosarcoma or liposarcoma. Also, this phase I study strongly supports the necessity for careful evaluation of combination therapies.     

Monovalent salt-induced gelation of enzymatically deesterified pectin

Pectin gels were induced by monovalent salts (0.2 M) concurrently with deesterification of high methoxy pectin using a salt-independent orange pectin methylesterase (PME). Constant pH was maintained during deesterification and gelation. If salt or PME was absent, the pectin did not form a gel. The gel strength was influenced by both pH and species of monovalent cation. At pH 5.0, the pectin gel induced by KCl was significantly stronger than the NaCl-induced gel. In contrast, a much stronger gel was produced in the presence of NaCl as compared to KCl at pH 7.0. LiCl did not induce pectin gelation at either pH. Molecular weights of pectins increased from 1.38 x 10(5) to 2.26 x 10(5) during NaCl-induced gelation at pH 7. One proposal to explain these pectin molecular weight changes is a hypothetical PME transacylation mechanism. However, these pectin molecular weight changes can also be explained by metastable aggregation of the enzymatically deesterified low methoxy pectin. We postulate that gelation was induced by a slow deesterification of pectin under conditions that would normally salt out (precipitate) low methoxy pectin in the absence of PME.     

Cultivating continuity and creating change: Women's home garden practices in northeastern Thailand

The tradition of planting and maintaining home gardens is an expression of culture and represents an intense interaction between humans and plants. Forty-nine home gardens in northeastern Thailand were surveyed and found to be quite rich and diverse. The gardens contained domesticated plants, species that are not native to the area, and local non-domesticates. We focused on women's gardening practices as behaviors that create an intensive interaction with the physical and social environment and found that women are increasing their management and manipulation of non-domesticated resources. Home gardens, maintained primarily by women, are part of a continuum of resource areas that are constructed and utilized. The maintenance of specific plants in the gardens provide a source of stability in the rapidly changing cultural, social, and economic environment.     

Risk factors for crop health under global change and agricultural shifts: a framework of analyses using rice in tropical and subtropical Asia as a model

Plant disease epidemiology requires expansion of its current methodological and theoretical underpinnings in order to produce full contributions to global food security and global changes. Here, we outline a framework which we applied to farmers' field survey data set on rice diseases in the tropical and subtropical lowlands of Asia. Crop health risks arise from individual diseases, as well as their combinations in syndromes. Four key drivers of agricultural change were examined: labor, water, fertilizer, and land availability that translate into crop establishment method, water shortage, fertilizer input, and fallow period duration, respectively, as well as their combinations in production situations. Various statistical approaches, within a hierarchical structure, proceeding from higher levels of hierarchy (production situations and disease syndromes) to lower ones (individual components of production situations and individual diseases) were used. These analyses showed that (i) production situations, as wholes, represent very large risk factors (positive or negative) for occurrence of disease syndromes; (ii) production situations are strong risk factors for individual diseases; (iii) drivers of agricultural change represent strong risk factors of disease syndromes; and (iv) drivers of change, taken individually, represent small but significant risk factors for individual diseases. The latter analysis indicates that different diseases are positively or negatively associated with shifts in these drivers. We also report scenario analyses, in which drivers of agricultural change are varied in response to possible climate and global changes, generating predictions of shifts in rice health risks. The overall set of analyses emphasizes the need for large-scale ground data to define research priorities for plant protection in rapidly evolving contexts. They illustrate how a structured theoretical framework can be used to analyze emergent features of agronomic and socioecological systems. We suggest that the concept of "disease syndrome" can be borrowed in botanical epidemiology from public health to emphasize a holistic view of disease in shifting production situations in combination with the conventional, individual disease-centered perspective.