Grass that doesn't need mowing

To some, "bioengineering" is a dirty word. Why mess with nature? But, since 1856, when Gregor Johann Mendel became the pioneer of plant genetics with his famous plant hybridization of peas, we have been manipulating plant genes to benefit humans. Now, we combine biochemistry, genetics and other biological sciences with engineering to improve people's lives.

In the realm of genetics, I have heard of breeders developing rectangular watermelons so they would pack better. They also developed tomatoes that would last longer without rotting to allow more time for shipping. Many grain crops have been improved to provide more food for the world's populations. Roses have been played with for years to create unusual colors, sizes and shapes. Trees, shrubs and flowers are always being hybridized.

What homeowner would object to breeders developing a lawn that never needs mowing? Imagine our summers being free of mowing chores Ð all that extra time, reduced gasoline use, reduced contribution to global warming and less grass clippings going to the landfill. Sounds pretty spectacular. After further research into the plant hormone, brassinosteroid, discovered 20 years ago, scientists are figuring out how to control the size of plants. Being able to control plant growth and size could provide significant beneficial impacts in the agriculture industry.

Brassinosteroids control cell expansion and are found in all plant cells. The more of these hormones a plant has, the bigger it is. It is conjectured that by limiting these hormones, plant growth could be contained to a preferred size. For example, grass could be developed to stop growing at 2 or 3 inches, and would never need mowing. Smaller trees could be developed to better meet the needs of today's smaller yards and congested cities. Hedges could grow to the size and shape you wanted them to grow, and never need pruning again. Think of all the horticultural possibilities.

Brassinosteroids actually serve several purposes. They help make the tips of plants grow and encourage the aging of leaves. They are beneficial in the germination of seeds, but may inhibit root growth. They help plants produce the tissues needed for water transport and prevent fruit from falling off too early. Brassinosteroids also increase a plant's resistance to freezing. And another important attribute is that they increase the yield of rice and wheat.

On the flip side, controlling the growth of plants could also have some detrimental effects. What would happen to all the people working in the landscape maintenance industry who normally would be mowing lawns or pruning hedges and trees? And, what would happen to the lawn mower industry? Thought provoking, isn't it?

For information on brassinosteroids, check out Kimball's online biology textbook, users.rcn.com/jkimball.ma.ultranet/BiologyPages/

For more information on gardening in Nevada, contact me at 887-2252 or skellyj@unce.unr.edu, or your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu. Ask a Master Gardener by e-mailing mastegardeners@unce.unr.edu.

-- JoAnne Skelly is the Carson City/Storey County Extension Educator for University of

Nevada Cooperative Extension.