Selecting maize for rapid kernel drydown: timing of moisture measurement

Previous studies have shown that maize ear moisture measured using a modified Electrophics Moisture Meter model MT808 was highly correlated to kernel moisture and could be used as a selection tool in breeding maize genotypes with faster rates of kernel drydown. Such a tool would need to be standardized for practical and routine use in a breeding program with large numbers of plants. The objective of this study was to determine the opti¬mum time for measuring ear moisture using this meter. In a split-plot design with three replicates in 2007, 2008 and 2009, ear moisture of six inbred lines and eight F1 hybrids were measured weekly from one to eight weeks post-silking using a modified MT808 moisture meter. To determine if multiple ear moisture readings (EMRs) could be made on the same ear, an additional treatment was added so that all eight readings were made on the same ear. There was a positive correlation between weekly EMRs readings done on separate ears and those done on the same ear, indicating that repeated readings, if desired, could be made on the same ear. Significant genotypic differences in EMRs were found five to eight weeks post-silking. The EMRs at week one, five, and eight could be used to calculate a daily drydown rate (DDR). Maize genotypes (hybrids and inbreds) could be divided into four groups based on their DDRs during development as: high-high, high-low, low-high, and low-low DDRs from weeks one to five and five to eight, respectively. Genotypes with higher DDRs from weeks one to five tended to have overall higher DDRs by eight weeks post-silking. Inbred lines with higher DDRs at either stage expressed this trait in their hybrid crosses. This non-destructive method will improve selection for fast kernel drydown in maize breed¬ing programs, especially in short-season areas

An integrated multi-study analysis of intra-subject variability in cerebrospinal fluid amyloid-β concentrations collected by lumbar puncture and indwelling lumbar catheter

INTRODUCTION: Amyloid-β (Aβ) has been investigated as a diagnostic biomarker and therapeutic drug target. Recent studies found that cerebrospinal fluid (CSF) Aβ fluctuates over time, including as a diurnal pattern, and increases in absolute concentration with serial collection. It is currently unknown what effect differences in CSF collection methodology have on Aβ variability. In this study, we sought to determine the effect of different collection methodologies on the stability of CSF Aβ concentrations over time. METHODS: Grouped analysis of CSF Aβ levels from multiple industry and academic groups collected by either lumbar puncture (n=83) or indwelling lumbar catheter (n=178). Participants were either placebo or untreated subjects from clinical drug trials or observational studies. Participants had CSF collected by lumbar puncture or lumbar catheter for quantitation of Aβ concentration by enzyme linked immunosorbent assay. Data from all sponsors was converted to percent of the mean for Aβ40 and Aβ42 for comparison. Repeated measures analysis of variance was performed to assess for factors affecting the linear rise of Aβ concentrations over time. RESULTS: Analysis of studies collecting CSF via lumbar catheter revealed tremendous inter-subject variability of Aβ40 and Aβ42 as well as an Aβ diurnal pattern in all of the sponsors' studies. In contrast, Aβ concentrations from CSF samples collected at two time points by lumbar puncture showed no significant differences. Repeated measures analysis of variance found that only time and draw frequency were significantly associated with the slope of linear rise in Aβ40 and Aβ42 concentrations during the first 6 hours of collection. CONCLUSIONS: Based on our findings, we recommend minimizing the frequency of CSF draws in studies measuring Aβ levels and keeping the frequency standardized between experimental groups. The Aβ diurnal pattern was noted in all sponsors' studies and was not an artifact of study design. Averaging Aβ concentrations at each time point is recommended to minimize the effect of individual variability. Indwelling lumbar catheters are an invaluable research tool for following changes in CSF Aβ over 24-48 hours, but factors affecting Aβ concentration such as linear rise and diurnal variation need to be accounted for in planning study designs

Potential of adopting bamboo as an alternative crop to smallholder tobacco farming in South Nyanza region, Kenya

The presentation provides findings from a study that examined changes in household livelihood strategies used by tobacco farmers in comparison to non-tobacco farmers, and assessed marketing dynamics for investment in the bamboo industry in the South Nyanza region (Kenya). At 120 farm trial sites, bamboo seedlings were planted under natural tobacco growing conditions (soil, altitude, rainfall and temperatures). Education and training were provided to farmers. Bamboo matures in 3-4 years and can be harvested for up to 80 -120 years with small capital investment. Recommendations include provision of a transitional fund to support initial input requirements

Potential of adopting bamboo as an alternative crop to smallholder tobacco farming in South Nyanza region, Kenya

The presentation provides findings from a study that examined changes in household livelihood strategies used by tobacco farmers in comparison to non-tobacco farmers, and assessed marketing dynamics for investment in the bamboo industry in the South Nyanza region (Kenya). At 120 farm trial sites, bamboo seedlings were planted under natural tobacco growing conditions (soil, altitude, rainfall and temperatures). Education and training were provided to farmers. Bamboo matures in 3-4 years and can be harvested for up to 80 -120 years with small capital investment. Recommendations include provision of a transitional fund to support initial input requirements