Eyespot resistance gene Pch-1 in H-93 wheat lines. Evidence of linkage to markers of chromosome group 7 and resolution from the endopeptídase locus Ep-Dlb

Gene Pch1, which confers resistance to eyespot disease (Pseudocercosporella herpotrichoides Fron), has been located on chromosome 7D in the H-93 wheat-Aegilops ventricosa transfer lines using isozyme markers and DNA probes corresponding to group 7 chromosomes. Previous experiments had failed to ascertain this location. The lack of segregation of the resistance trait in progeny from reciprocal crosses between lines H-93-70 and VPM1 indicates that their respective resistance factors are allelic. Line H-93-51 carries the endopeptidase allele Ep-D1b but is susceptible to eyespot, which indicates that resistance to eyespot is not a product of the Ep-D locus, as had been proposed in a previous hypohesi

Resistance to the cereal cyst nematode (Heterodera avenae) transferred from the wild grass Aegilops ventricosa to hexaploid wheat by a "stepping-stone" procedure

Transfer of resistance toHeterodera avenae, the cereal cyst nematode (CCN), by a stepping-stoneprocedure from the wild grassAegilops ventricosa to hexaploid wheat has been demonstrated. The number of nematodes per plant was lower, and reached a plateau much earlier, in the resistant introgression line H93-8 (1–2 nematodes per plant) than in the recipient H10-15 wheat (14–16 nematodes per plant). Necrosis (hypersensitive reaction) near the nematode, little cell fusion, and few, often degraded syncytia were observed in infested H93-8 roots, while abundant, well-formed syncytia were present in the susceptible H10-15 wheat. Line H93-8 was highly resistant to the two Spanish populations tested, as well as the four French races (Fr1-Fr4), and the British pathotype Hall, but was susceptible to the Swedish pathotypes HgI and HgIII. Resistance was inherited as though determined by a single quasi-dominant factor in the F2 generations resulting from crosses of H93-8 with H10-15 and with Loros, a resistant wheat carrying the geneCre1 (syn.Ccn1). The resistance gene in H93-8 (Cre2 orCcn2) is not allelic with respect to that in Loros. RFLPs and other markers, together with the cytogenetical evidence, indicate that theCre2 gene has been integrated into a wheat chromosome without affecting its meiotic pairing ability. Introduction ofCre2 by backcrossing into a commercial wheat backgroud increases grain yield when under challenge by the nematode and is not detrimental in the absence of infestation

Genetic diversity trends in twentieth century crop cultivars: a meta analysis

In recent years, an increasing number of papers has been published on the genetic diversity trends in crop cultivars released in the last century using a variety of molecular techniques. No clear general trends in diversity have emerged from these studies. Meta analytical techniques, using a study weight adapted for use with diversity indices, were applied to analyze these studies. In the meta analysis, 44 published papers were used, addressing diversity trends in released crop varieties in the twentieth century for eight different field crops, wheat being the most represented. The meta analysis demonstrated that overall in the long run no substantial reduction in the regional diversity of crop varieties released by plant breeders has taken place. A significant reduction of 6% in diversity in the 1960s as compared with the diversity in the 1950s was observed. Indications are that after the 1960s and 1970s breeders have been able to again increase the diversity in released varieties. Thus, a gradual narrowing of the genetic base of the varieties released by breeders could not be observed. Separate analyses for wheat and the group of other field crops and separate analyses on the basis of regions all showed similar trends in diversity

Exploitation of a preferentially transmitted chromosome from <i>Aegilops sharonensis</i> for the elimination of segregation for height in semidwarf bread wheat varieties

Certain semidwarf bread wheat varieties tend to lose chromosome 4D, carrying the dwarfing gene Rht2, resulting in the production of tall "offtypes." To overcome this problem translocations have been isolated involving the arm of the Aegilops sharonensis chromosome 4S1 that carries the genes determining preferential transmission and the Rht2-carrying arm of chromosome 4D of Triticum aestivum. These translocations, which were derived by self-pollinating plants doubly monosomic for chromosomes 4D and 4S1, appear to be preferentially transmitted in both pollen and egg, thus ensuring constant disomy and homozygosity of Rht2.Key words: preferential transmission, translocation, Triticum aestivum, Aegilops sharonensis. </jats:p

Developing a framework for arts in health programs targeting individuals with chronic pain: a mixed-methods study of practitioners

Objectives: Chronic pain is a leading cause of morbidity and disability across the world. Cultural engagement may be a valuable tool in addressing the social disconnection that often accompanies chronic pain. This study sought to develop a framework for arts in health programs targeting individuals with chronic pain. Study design: Sequential explanatory mixed-methods study. Methods: Web-based, cross-sectional survey sent to arts and cultural professionals to assess their experience with arts in health programming. Semi-structured interviews conducted with a sample of survey respondents to explore their perspectives on targeted arts in health programming for individuals with chronic pain. Results: Between October 2019 and January 2020, 208 surveys were completed by arts and cultural professionals. One hundred and twenty (58%) of the respondents indicated that they currently run an arts in health or museums in health program. Among these 120 respondents, 52 (43%) targeted older adults, 50 (42%) targeted individuals with mental health concerns, and 18 (15%) targeted individuals living with pain. Improving well-being (101 [84%]) and reducing social isolation (90 [75%]) were the most common intended program outcomes, while improving pain was the least common outcome (26 [22%]). Fifteen survey respondents were interviewed. Interviewees identified four interdependent themes regarding best practices for arts in health programs pertaining to (1) program content and structure, (2) program facilitation, (3) partnerships, and (4) programs for individuals with chronic pain. Conclusions: The cultural sector can support chronic pain prevention and treatment efforts through the development of specialized programs. This study provides a framework for developing arts in health programs that support individuals living with chronic pain

Plant genome sequencing: applications for crop improvement

DNA sequencing technology is undergoing a revolution with the commercialization of second generation technologies capable of sequencing thousands of millions of nucleotide bases in each run. The data explosion resulting from this technology is likely to continue to increase with the further development of second generation sequencing and the introduction of third generation single-molecule sequencing methods over the coming years. The question is no longer whether we can sequence crop genomes which are often large and complex, but how soon can we sequence them? Even cereal genomes such as wheat and barley which were once considered intractable are coming under the spotlight of the new sequencing technologies and an array of new projects and approaches are being established. The increasing availability of DNA sequence information enables the discovery of genes and molecular markers associated with diverse agronomic traits creating new opportunities for crop improvement. However, the challenge remains to convert this mass of data into knowledge that can be applied in crop breeding programs