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GM CROPS IN CALIFORNIA Large Acreage: Cotton RON VARGAS, FARM ADVISOR UNIVERSITY OF CALIFORNIA COOPERATIVE EXTENSION Madera/Merced Counties Progression of GM Cotton in San Joaquin Valley 1996 Small UCCE Research Studies 1997 Small experimental acreage 600 RR < 100 BXN 1998 1st commercial plantings 1,200 RR 1,000 BXN 1999 Acreage increased dramatically when SJV “One Quality” law changed 85,000 RR 14,000 BXN 2000 227,000 RR 68,000 BXN 2001 235,000 RR 70,000 BXN 2002 173,000 RR 24,000 BXN (42,000 RR + Bt) (some staked gene RR/ Bt) (3,130 RR/ Bt) (351 Bt) Transgenic Herbicide Tolerant Cotton • Allowed grower to effectively control most annual and perennial weeds • Reduce or eliminate hand hoeing and cultivation • Cost Savings – range from $25 - $120/acre • Explore alternative production systems – Conservation/reduced tillage – Ultra narrow row Limitations • BXN – broadleaf control only – tank mix with grass herbicides • RR – small window of application, heavy penalty in yield, and some extent quality, for off-label applications • Difficult to control weeds-nutsedge, field bindweed, annual morningglory Integrated Weed Management System • These systems can be very useful as another weed control option to supplement existing weed control programs based upon the use of pre-plant, selective over-the-top and layby herbicides. Decision to Use Transgenic Herbicide Tolerant Cottons • • • • • • • Weed species present (annuals vs. perennials) Density and extent of weed population Is weed pressure enough to impact yield? Is hand weeding or cultivation eliminated? Cost of alternative herbicides Cost of technology fee Are there well suited transgenic varieties with favorable agronomic characteristics (yield and quality)? Weed Resistance Concerns • If weed control programs are developed which solely rely on one type of herbicide there is a high probability of developing resistant weed species and/or weed shifts. • Example: – annual ryegrass, marestail – Growers have reported poor control of barnyardgrass and lambsquater Resistance Management • A well balanced long-term weed management approach must incorporate resistance management strategies: – Crop rotation – Herbicide rotation – Control of weed escapes by hand or tillage Future Developments • Enhanced Roundup Ready varieties – wider window of application • Liberty link cotton varieties Bt and Bollgard Varieties • Especially suited for pink bollworm and budworm – not problems in California • Fewer total pesticide sprays required since fewer worms • Insect resistance and refuge issues Concerns • How to segregate transgenic from conventional varieties (starlink corn) • Transgenic cotton seed as animal feed (studies to date of protein and amino acids are equivalent to conventional varieties • Development of “super weed” – genetic shifts in weeds resulting in potential to increase weed problems Concerns contd. • Impact on non-target organisms (beneficial insects and butterflies • Changes in dominant insect pest: with changes in spray programs with Bt cotton – do pests that once were secondary become more damaging with reduced pesticide applications? Other Large Acreage GM Crops • Corn, 40-50,000 Acres in 2002 • Rice • Alfalfa