Program Area 5.

Assessing the Effects of Bt Crops and Insecticides
On Arbuscular Mycorrhizal Fungi and
Plant Residue Carbon Turnover and Fate in Soil

Principal Investigator(s):

  • Medha Devare - Cornell University

  • Janice Thies - Cornell University

  • John Duxbury - Cornell University

The enormous progress made in developing and disseminating insect-resistant Bt crop varieties is exciting from the perspective of increasing productivity and decreasing environmental and human health hazards posed by the insecticides normally used to contain pest damage. However, concerns regarding the use of this technology have been expressed, among the foremost of which is its potential impact on non-target organisms. To date, there have been few assessments to determine if this technology poses any risks to the biomass and diversity of microorganisms in the soil. Further, it is not clearly understood whether potential variations in the dynamics of carbon allocation and in field rates of residue decomposition between transgenic and non-transgenic plants have implications for carbon sequestration in soil.

We propose to determine the effect of Bt corn, cotton, and rice on soil organisms--with an emphasis on symbiotic associations between plant roots and arbuscular mycorrhizal (AM) fungi known as vesicular arbuscular mycorrhizae (VAM) and on soil arthropods important in primary decomposition of crop residue. We will also compare the rates of decomposition and fate of Bt vs. non-Bt residue and evaluate the potential for increasing carbon sequestration in soil using Bt crops. The crops have been chosen so that we can evaluate effects on soil organisms under both aerobic and anaerobic circumstances: Bt corn and cotton are grown in aerobic soil while Bt rice is grown in primarily anaerobic soil conditions. Through this work, we hope to provide regulatory agencies with a more complete picture of the ways in which diversely grown Bt crops affect soil ecology in comparison with commonly used insecticides.

Annual Report: biotech_cornell_2006-2007 **new (242 Kilobytes)

Genetic Characterization of Adaptive Root Traits
In the Common Bean

Principal Investigator(s):

  • C. Eduardo Vallejos - University of Florida

  • James Jones - University of Florida

The work we are proposing is in line with the USAID strategic objectives aimed at developing products that overcome soil-management constraints in different agricultural settings. Identification and molecular tagging of genes that control root growth and morphology will facilitate the development of cultivars suitable for specific soil conditions. For instance breeding cultivars that have a strong basal root system in the top soil capable of efficiently extracting phosphorus.

This project will combine two technologies not commonly used in the study of roots: magnetic resonance imaging (MRI) and quantitative trait loci (QTL) analysis with molecular markets.

Annual Report: biotech_florida_2006-2007 **new (2,105 Kilobytes)

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