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Hop with powdery mildew [HPM: caused by Podosphaera macularis (Wallr.) U. Braun & S. Takam.] results in significant losses in hop production by reducing yield and quality. One means of increasing yield and quality is the production of resistant hop lines. Breeding for resistance can be significantly improved and accelerated by use of marker-assisted selection. The objective of this preliminary study was to identify QTLs and markers for genetic resistance to HPM. A bi-parental mapping population between the resistant line “Newport” and susceptible line ‘21110M’. Phenotypic data was scored under controlled greenhouse conditions. Significant differences among offspring were observed and disease resistance did not follow a distinct binomial distribution, suggesting quantitative genetic control. Genotyping-by-sequencing resulted in approximately 375 K SNP markers, which were filtered down to 2263 markers mapped to 10 linkage groups. Interval Mapping identified four QTLs with one on linkage group 1 and three located on linkage group 6. Composite interval mapping identified three QTLs, all located on linkage group 6. Mixed linear models identified 15 markers associated with expression of resistance to HPM. Three of these 15 SNPs were also identified in QTL-CIM analysis. Evaluation of the scaffolds containing the significant SNP markers identified seven putative genes—several of which appear involved in disease resistance in other plant species. The SNP markers identified in this study still require validation in unrelated populations prior to implementation in breeding programs. [ABSTRACT FROM AUTHOR]

Identification of heterotic groups and patterns among breeding populations provides fundamental information to help plant breeders more knowledgeably manipulate heterosis. A diallel analysis was conducted among nine alfalfa (Medicago sativaL.) germplasms, commonly referred to as African, Chilean, Flemish, Indian, Ladak,M. falcata,M. varia, Peruvian, and Turkistan, which represent a significant proportion of the genetic diversity present in US cultivars. Heterotic responses were determined by evaluating forage yield of the germplasms and their 36 half-diallel hybrids in seeded plots that were harvested five times in each of 2 years. Commercially acceptable yields were obtained from some hybrids of unimproved parents, where at least one parent was adapted to the study environment. Variation among crosses was attributed primarily to general combining ability (GCA) effects; however, specific combining ability effects were also significant. GCA estimates for African, Chilean and Peruvian were positive, while those for Ladak,M. falcata, andM. variawere negative. Estimates for variety heterosis effects were positive for Peruvian andM. falcataand negative for Indian andM. varia. Significant mid-parent heterosis [(MPH) range of -21% to 55%] and high-parent heterosis [(HPH) range of -33% to 23%] was detected.M. falcatahybrids exhibited the highest MPH values. However, this likely reflects the poor yield ofM. falcataper se in the study environment and consequently, low MPH values. Peruvian hybrids demonstrated the highest cross mean performance, significant positive MPH in all crosses, and positive HPH in five out of eight crosses. The results indicate that Peruvian should be recognized as a heterotic group. Alfalfa breeders may wish to explore opportunities for heterotic yield gains that are likely to exist in hybrids between the Peruvian germplasm and elite breeding populations, in particular, those adapted to the southwestern United States. MPH results suggest that alfalfa breeders may have capitalized on the heterotic response between Flemish andM. variaduring past development of alfalfa synthetics adapted to the central and northern latitudes of the United States. [ABSTRACT FROM AUTHOR]

Although individuals with poor food security might be expected to have reduced food intake, and thus reduced body fat and less likelihood of being overweight, these associations have not been adequately studied. The purpose of the current study was to examine the relationship between food insecurity and overweight as measured by body mass index (BMI) using data from the nationally representative 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII). Overweight was defined as BMI >27.3 kg/m(2) for women and 27.8 kg/m(2) for men. Food insecurity was related to overweight status for women (n = 4509, P < 0.0001), but not for men (n = 4970, P = 0.44). Excluding the 11 severely insecure women, the prevalence of overweight among women increased as food insecurity increased, from 34% for those who were food secure (n = 3447), to 41% for those who were mildly food insecure (n = 966) and to 52% for those who were moderately food insecure (n = 86). Food insecurity remained a significant predictor of overweight status, after adjustment for potentially confounding demographic and lifestyle variables (P < 0.01). In a logistic regression analysis, mildly insecure women were 30% more likely to be overweight than those who were food secure [odds ratio (OR) 1.3, P = 0.005]. Thus, food insecurity had an unexpected and paradoxical association with overweight status among women with a higher prevalence of overweight among the food insecure, and a resulting potential for increased incidence of obesity-related chronic diseases. Given that the rates of both overweight and food insecurity are on the rise, this research area warrants further investigation. [ABSTRACT FROM AUTHOR]