BBT413_L1.pdf

Plant Biochemistry & Biotechnology Stages of Biotechnological Development WHY FARMERS USE BIOTECH CROPS The primary driver of adoption among farmers (both large commercial and small-scale subsistence) has been the positive impact on farm income. The adoption of bio...

Plant Biochemistry & Biotechnology Stages of Biotechnological Development WHY FARMERS USE BIOTECH CROPS The primary driver of adoption among farmers (both large commercial and small-scale subsistence) has been the positive impact on farm income. The adoption of biotechnology has had a very positive impact on farm income derived mainly from a combination of enhanced productivity and efficiency gains. In 2005, the direct global farm income benefit from GM crops was $5 billion. The economic gains derived from planting GM crops have been of two main types: (1) increased yields (associated mostly with GM insect-resistant technology) and (2) reduced costs of production derived from less expenditure on crop protection (insecticides and herbicides) products and fuel. Herbicide-Tolerant Crops In a conventional crop, post emergent weed control relies on herbicide applications before the weeds and crop are well established. As a result, the crop may suffer “knockback” to its growth from the effects of the herbicide. In the GM HT crop, this problem is avoided because the crop is tolerant to the herbicide and spraying can occur at a later stage when the crop is better able to withstand any possible knockback effects. This method facilitates the adoption of conservation or no-tillage systems. This provides for additional cost savings such as reduced labor and fuel costs associated with plowing. Improved weed control has contributed to reduced harvesting costs—cleaner crops have resulted in reduced times for harvesting. It has also improved harvest quality and led to higher levels of quality price bonuses in some regions (e.g., Romania). Potential damage caused by soil-incorporated residual herbicides in follow-on crops has been eliminated. Insect-Resistant Crops A “convenience” benefit is derived because less time is spent walking through the crop fields to survey insects and insect damage and/or apply insecticides. Savings in energy use are realized—associated mainly with less frequent aerial spraying. There are savings in machinery use (for spraying and possibly reduced harvesting times). The quality of Bt maize is perceived as superior to that of non-Bt maize because the level of fungal (Fusarium) damage, which leads to mycotoxin presence in plant tissues, is lower with Bt maize. As such, there is an increasing body of evidence that Fusarium infection levels and mycotoxin levels in GM insect resistant maize are significantly (5–10-fold) lower than those found in conventional (nonbiotech) crops. This lower mycotoxin contamination in turn leads to a safer food or feed product for consumption. There Health and safety for farmers and farmworkers is improved (handling and use of pesticides is reduced). The growing season is shorter (e.g., for some cotton growers in India), which allows some farmers to plant a second crop in the same season (notably maize in India). Also some Indian cotton growers have reported commensurate benefits for beekeepers as fewer bees are now lost to insecticide spraying. quality of Bt maize is perceived as superior to that of non-Bt maize  Fungal damage leads to the increased synthesis of mycotoxin Level of mycotoxin is higher in Non-Bt maize compared to Bt maize HOW THE ADOPTION OF PLANT BIOTECHNOLOGY HAS IMPACTED THE ENVIRONMENT The two key aspects of environmental impact of biotech crops examined below are decreased insecticide and herbicide use, and the impact on carbon emissions and soil conservation. Environmental Impacts from Changes in Insecticide and Herbicide Use Impact on Greenhouse Gas (GHG) Emissions Reduce fuel use reduces GHG A shift from conventional tillage to NO/reduced tillage The use of reduced/no-tillage farming systems that utilize less plowing increase the amount of organic carbon in the form of crop residue that is stored or sequestered in the soil. This carbon sequestration reduces carbon dioxide emissions to the environment. Biotechnological application for Plants Acquire Knowledge of Plant Biochemistry Molecular Biological/Biotechnological techniques Construction of suitable expression vectors Transformation Regeneration Next Topic: Structure of the Leaf Cell