LD2668 .T4 1962 S57

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A total of 200 Rhizobium meliloti isolates were sampled from alfalfa (Medicago sativa L.) nodules in five uninoculated fields throughout Arizona. Dominant strains (≥ 20% nodule occupancy at each site) were identified using plasmid profile analysis and intrinsic antibiotic resistance patterns. The major dominant strains and a commercial strain (102F77b) were evaluated for their N fixing effectiveness in a Leonard jar study. All strains were highly effective, and no significant differences were found (p ≥ 0.05) in shoot weight, root weight, nodule weight, acetylene reduction and total N content among the strain treatments. These effective dominant R. meliloti strains indigenous to Arizona soil probably contribute to the state's high alfalfa yield. Furthermore, indigenous strains AZTCYJ, AZSC, and AZY have potential as inoculants for arid lands due to their high effectiveness and unique resistances to extreme abiotic stresses present in arid land soils.

Call number: LD2668 .T4 1986 S36 / Master of Science / Horticulture, Forestry, and Recreation Resources

Digitized by Kansas Correctional Industries

Pest status of the rice stem-borers, Diopsis longicornis and D. apicalis was not well known in the Republic of Guinee. / In the present study, adult and immature populations of both species were monitored under various local cultural practices, i.e., planting methods (direct and transplanted), different planting dates and seasons (wet and dry). As previously observed in other West African countries, D. apicalis did occasional damage to rice in Guinee. However, contrary to findings elsewhere, D. longicornis was not an important pest of Guinean rice, infesting 4% of stems over the five seasons studied. / Regulators affecting population size and behaviour of D. longicornis were determined, focusing on factors controlling the fly's quiescent period in aggregation sites during the dry season, and the insect's movement to and from these refugia. Availability of cultivated and wild rice was found to interrupt or prevent quiescence of D. longicornis. Abiotic factors, (relative humidity, rainfall and photoperiod) influenced time of dispersal of D. longicornis.

This thesis uses laboratory and field experiments to examine the underlying motivations that drive biased and discriminatory behaviour. Its focus is on the differential treatment of others that stems from individuals’ preferences for particular social and ethnic groups. The unifying theme of this thesis is the exploration of how such discriminatory tastes can manifest themselves within individuals’ social and other–regarding preferences, determining the extent to which they care about the welfare of others. The prevalence and implications of these types of preferences are considered in both market and non–market settings.

This thesis is aimed at forecasting of experimental results in a lab environment, investigating often discussed external validity of laboratory experiments. We run a novel laboratory experiment in which the subject pool is asked to make predictions on results of a certain field experiment. The collected data is ana­ lyzed using different accuracy measures, arriving at several interesting results. First, the forecast among the 94 subjects is quite informative about the actual treatment effects although its accuracy substantially varies based on a type of accuracy measure and a particular treatment. Second, the average forecast is either more accurate or at least comparable to the mean individual forecast, proving the presence of "wisdom-of-crowds" effect.

Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Agronomy))--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

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