Featured Research

from universities, journals, and other organizations

If GMO genes escape, how will the hybrids do? Fitness and growth of sorghum, shattercane, and its wild-crop hybrid in Nebraska

Date:
November 2, 2010
Source:
American Journal of Botany
Summary:
Genetically modified organisms (GMOs) may raise concerns of genes escaping from crops and having unknown effects on natural, wild species. But what is the real risk that traits associated with GMOs will actually migrate to and persist in their wild relatives? Interest in plant ecology, crop production and weed management led researchers to investigate how gene flow from a cultivated crop to a weedy relative would influence the ecological fitness of a cropwild hybrid offspring.

GMOs, or genetically modified organisms, may raise concerns of genes escaping from crops and having unknown effects on natural, wild species. But what is the real risk that traits associated with GMOs will actually migrate to and persist in their wild relatives? Interest in plant ecology, crop production and weed management led John Lindquist and his colleagues from the University of Nebraska and USDA-ARS to investigate how gene flow from a cultivated crop to a weedy relative would influence the ecological fitness of a cropwild hybrid offspring.

They published their findings in the recent October issue of the American Journal of Botany.

Grain sorghum (Sorghum bicolor subsp. bicolor) is an important food and feed crop throughout the world. The reduced digestibility of sorghum seed relative to other grains makes it a less efficient resource, even though it is highly adapted to growth in semiarid environments common to Africa, India, and the Southern and Western Great Plains of the United States. There has been considerable interest in modifying the quality traits of grain sorghum using GMO technology to enhance its nutritional value to both humans and animals raised for human consumption.

A major challenge to sorghum producers is the limited number of products available to control weeds within the crop -- too many of the common products cause crop damage. To address this challenge, one of the major U.S. seed companies is developing herbicide-resistant grain sorghum using traditional breeding (non-GMO) strategies and plans to deploy them in the United States within the next 5 years.

There is inherent risk in deploying grain sorghum containing novel genes because several related species (e.g., johnsongrass, shattercane) are capable of interbreeding with grain sorghum.

Lindquist and his colleagues focused their research on gene flow between sorghum and its closely related, wild, weedy relative, shattercane (Sorghum bicolor subsp. drummondii). Lack of information on the potential gene flow from grain sorghum to shattercane is an important problem because it limits our fundamental understanding of gene transfer and potential hybridization between grain sorghum and shattercane. Their goal was to obtain baseline data using non-GMO sorghum and shattercane that would improve our ability to assess the potential risks of introducing novel genes in grain sorghum into U.S. agroecosystems.

Variation in alleles contributes to the ability of a population to adapt to a variable environment. Yet, this variation is often controlled in cultivated crops for ease of production -- for example, with sorghum, all seeds germinate at roughly the same time, plants grow to a uniform height, and seeds ripen at the same time. In contrast, shattercane has seeds with variable states of dormancy, plants that grow taller than sorghum, and seeds that disperse via a shattering mechanism, ensuring dispersal before the sorghum crop is harvested. By crossing shattercane with cultivated sorghum, the authors compared how the crop-wild hybrid performed relative to its crop and wild parents in a number of traits that may be important to its ecological fitness.

By experimentally manipulating temperature conditions, the authors found different germination patterns for the three types of seeds. Although the crop-wild hybrid responded to low temperatures similarly to its wild shattercane parent -- both in terms of percentage of seeds that germinated and by staying dormant and delaying germination -- it responded to high temperatures similarly to its cultivated sorghum parent; non-germinated seeds of both sorghum and the hybrid died. This may be linked to their seed structures. Shattercane seeds are completely enclosed by glumes, whereas those of sorghum are only partially covered, a factor that makes them much easier to mill but does not protect them well from environmental extremes. The glumes on the hybrids are more similar to sorghum, so it is possible that despite their ability to be dormant, they may not survive well in extreme environmental conditions.

When the authors compared growth factors under natural field conditions, they found that the hybrid grew taller than either of its parent types, had greater leaf area than the shattercane but less than sorghum, and leaf emergence was earlier than in the shattercane. The authors speculate that if the three types were grown in mixture in the field, the hybrid would likely be able to capture more light and thus be more competitive than the two parent types. However, the hybrid produced fewer seeds than either sorghum or shattercane (although they were similar to shattercane at one site).

"Genes from grain sorghum, including a transgene or a traditionally bred specialty trait such as the herbicide resistance traits in sorghum, could be successfully transferred to a weedy shattercane population," Lindquist concludes. Indeed, in this case the relative fitness of the hybrid may be equivalent to that of the wild parent.

However, further research is needed. "It is imperative to know the rate of outcrossing from sorghum to shattercane," Lindquist emphasizes. "In other words, what proportion of seed on a shattercane plant will be pollinated by a nearby grain sorghum population, and how far can that pollen go?"

"Next, we want to be able to predict the overall likelihood that a gene from grain sorghum will enter the weedy shattercane population."


Story Source:

The above story is based on materials provided by American Journal of Botany. Note: Materials may be edited for content and length.


Journal Reference:

  1. L. Sahoo, J. J. Schmidt, J. F. Pedersen, D. J. Lee, J. L. Lindquist. Growth and fitness components of wild x cultivated Sorghum bicolor (Poaceae) hybrids in Nebraska. American Journal of Botany, 2010; 97 (10): 1610 DOI: 10.3732/ajb.0900170

Cite This Page:

American Journal of Botany. "If GMO genes escape, how will the hybrids do? Fitness and growth of sorghum, shattercane, and its wild-crop hybrid in Nebraska." ScienceDaily. ScienceDaily, 2 November 2010. <www.sciencedaily.com/releases/2010/11/101101171246.htm>.
American Journal of Botany. (2010, November 2). If GMO genes escape, how will the hybrids do? Fitness and growth of sorghum, shattercane, and its wild-crop hybrid in Nebraska. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2010/11/101101171246.htm
American Journal of Botany. "If GMO genes escape, how will the hybrids do? Fitness and growth of sorghum, shattercane, and its wild-crop hybrid in Nebraska." ScienceDaily. www.sciencedaily.com/releases/2010/11/101101171246.htm (accessed September 21, 2014).

Share This



More Plants & Animals News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins