Evaluation of three methods of teaching ninth grade algebra

This item was digitized by the Internet Archive. Thesis (Ed.M.)--Boston Universit

Research Notes : Flavonol classes of cultivars in Maturity Groups 00-IV

Since the complementary action of Fg1 and Fg3 in producing kaempferol 2G-glucosyl-gentiobioside (Buttery and Buzzell, 1975) is associated with deleterious effects on chlorophyll concentration, photosynthetic rate and yield (Buttery and Buzzell, 1976), the bringing together of these two genes in crosses may necessitate selection against the Fg1-Fg3-genotype in the segregating material. For example, with the cross of \u27Corsoy\u27 (Fg1 fg3) x \u27Hawkeye\u27 (fg1 Fg3) at Iowa State University, visual selection was carried out against chlorophyll deficient types during inbreeding in order to develop lines for a physiological study. At the time of selection it was not known that flavonol-glycoside genes were involved. Advanced lines were later classified using thin layer chromatography (Buttery and Buzzell, 1973

Soybean Residual Effects on a Subsequent Maize Crop

Maize (Zea mays 1.) grown after soybean (Glycine max 1. Merr.) consistently performs better than maize that follows itself (second year maize), irrespective of nitrogen fertilization. In previous studies of the soybean-maize rotation, there never has been an evaluation of the potentially different effects of soybean genotypes on following maize. A two-year, soybean maize rotation was initiated in Ames at 1988 with the first year planted to various soybean genotypes, a maize hybrid, and oat (Avena sativa 1.). These were followed in the second year by a single maize hybrid with 0, 80, 160, and 240 kg/ha N fertilization levels. Results are based on three repetitions of this cycle. Averaged over all years and N rates, maize after nodulated soybean and oat yielded 1270 and 1570 kg/ha, 16 and 20% respectively, more than second-year maize. Second-year maize was delayed in silking by 4 days. Though soybean returned 60 to 70 kg/ha of N to the soil in vegetative residue, there seemed to be no net N contribution from soybean to maize because soybean benefited maize less at zero N than did unharvested oat. Soybean evidently returns to the soil less N than is mineralized from soil organic matter during a cropping year. Prior soybean and oat both benefited maize even under the highest nitrogen fertilization rate. BSR 201 soybean benefited maize more than did the other soybean cultivars or oat. Averaged for years and the two highest N rates, BSR 201 benefited maize 680 kg/ha (ca 11 bu/A) more than all the other nodulated soybean genotypes averaged. The BSR 201 effect, however, was not consistent, occurring in two of the three years. Work is continuing using other BSR types

For corn and soybeans - Narrow Rows

There\u27s yield advantage, but costs, too, in narrow rows as compared to 40-inch rows for corn and soybeans. Since costs of changing to narrow rows will vary from farm to farm, each farmer must decide his own best time, if ever, to change

Chlorophyll Meter Assessments of Corn Response to Nitrogen Management Practices

Environmentally sound nitrogen (N) management is necessary to simultaneously achieve high crop yields and protect surface and groundwater quality. We evaluated a hand-held chlorophyll meter as a diagnostic tool for improving management for corn (Zea mays L.). Five N fertilizer rates (0, 67, 134, 201 and 280 kg N ha-1) were evaluated in one study, and in a second study, the meter was used to evaluate the N status of corn plants grown under varying tillage (chisel plow vs no-till), crop rotation (continuous corn vs corn-soybean [Glycine max (L.) Merr.]), and N management treatments. Meter readings were taken at several plant growth stages in both studies and correlated with plant N concentrations and grain yield. The chlorophyll meter readings detected differences in corn plants receiving low and high fertilizer N rates, as well as those grown with different tillage, N fertilizer management, and crop rotation practices. We recommend taking measurements between plant growth stages V9 and V12 and conclude that chlorophyll meters can be effective tools for improving N fertilizer management

Heterologous Expression of ATG8c from Soybean Confers Tolerance to Nitrogen Deficiency and Increases Yield in Arabidopsis

Nitrogen is an essential element for plant growth and yield. Improving Nitrogen Use Efficiency (NUE) of crops could potentially reduce the application of chemical fertilizer and alleviate environmental damage. To identify new NUE genes is therefore an important task in molecular breeding. Macroautophagy (autophagy) is an intracellular process in which damaged or obsolete cytoplasmic components are encapsulated in double membraned vesicles termed autophagosomes, then delivered to the vacuole for degradation and nutrient recycling. One of the core components of autophagosome formation, ATG8, has been shown to directly mediate autophagosome expansion, and the transcript of which is highly inducible upon starvation. Therefore, we postulated that certain homologs of Saccharomyces cerevisiae ATG8 (ScATG8) from crop species could have potential for NUE crop breeding. A soybean (Glycine max, cv. Zhonghuang-13) ATG8, GmATG8c, was selected from the 11 family members based on transcript analysis upon nitrogen deprivation. GmATG8c could partially complement the yeast atg8 mutant. Constitutive expression of GmATG8c in soybean callus cells not only enhanced nitrogen starvation tolerance of the cells but accelerated the growth of the calli. Transgenic Arabidopsis over-expressing GmATG8c performed better under extended nitrogen and carbon starvation conditions. Meanwhile, under optimum growth conditions, the transgenic plants grew faster, bolted earlier, produced larger primary and axillary inflorescences, eventually produced more seeds than the wild-type. In average, the yield was improved by 12.9%. We conclude that GmATG8c may serve as an excellent candidate for breeding crops with enhanced NUE and better yield

Beyond “Political” Communicative Spaces: Talking Politics on the Wife Swap Discussion Forum

Net-based public sphere researchers have examined online deliberation in numerous ways. However, most studies have focused exclusively on political discussion forums. This article moves beyond such spaces by analyzing political talk from an online forum dedicated to reality television. The purpose is to examine the democratic quality of political talk that emerges in this space in light of a set of normative criteria of the public sphere. The analysis also moved beyond an elite model of deliberation by investigating the use of expressives (humor, emotional comments, and acknowledgments). The findings reveal that participants engaged in political talk that was often deliberative. It was a space where the use of expressives played a significant role in enhancing such talk