2 weeks Ago
Question: I love to try new, improved plant varieties. Could you share with us how new varieties are developed? Answer: The processes for developing new plant varieties have changed dramatically over hundreds of years. Changes are continuing at a more rapid pace in recent years.
Man began changing the plants he grew as soon as he domesticated and cultivated them instead of just gathering them. He began by selecting seed from the most productive plants for next year’s planting. For thousands of years, this was the only method of getting the best from nature’s diversity.
In the early 1900s, gene-controlled heredity was discovered. Scientists began cross-breeding diverse individual plants to produce a broader diversity to choose from than nature provided. For most of the 20th century, hybridization was the main plant breeding method used by professionals.
Additional steps were added to make sure that improved strains of plants could be reproduced consistently. First, plants were self-pollinated or inbred for multiple generations to develop uniformity in the particular characteristics desired. Then the uniform inbred plants were used as parents to cross-pollinate plants with other desirable characteristics.
Because the two parent plant strains were uniform, they passed on these uniform characteristics reliably every time the parents were cross-pollinated. This crossing of distinctly different parents also produced hybrid vigor and greater productivity. This hybrid method required numerous generations of selection and back-crossing when only one characteristic, such as disease resistance, was wanted from one parent.
Crossing was limited to plants between one species, or a closely related species. If no gene for disease resistance was found in cultivated or wild populations of the species, it was not possible to develop resistant plants. During the last 20 years, techniques for transferring a single gene from a totally unrelated species by a process known as gene splicing have made dramatically rapid progress possible.
Many major crops, such as cotton, soybeans and corn are grown from varieties that have resistance to almost every major insect and disease. Strains that are resistant to weed killers are also widely used. This has not only increased yields but has reduced production costs and environmental impacts.
Since gardeners prefer to buy started plants rather than seeds for ornamental plants, it does not matter whether the plant was grown from seed or tissue culture..
