Heterosis in agriculture

Published on December 1, 2013   53 min

A selection of talks on Plant & Animal Sciences

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Hello. My name is Nathan Springer. I am a professor in the Department of Plant Biology at the University of Minnesota. My lab studies maize genetics. And we have done some research on the phenomena of heterosis. Today, I will be talking about heterosis in agriculture.
It is useful to begin with an outline of what I will talk about today. First, I want to discuss what is heterosis, what is the meaning of this word, and what are we describing when we use this word? Second, what is the genetic basis of heterosis? Heterosis is a complex phenomenon. And it would be useful to better understand the genetic processes that might contribute to heterosis. Third, what are the implications of heterosis for agriculture? Heterosis is widely used in agricultural systems throughout the world. And it has some strong implications for both how seed is produced to go into fields, as well as the yield and the types of plants that are utilized.
So what is heterosis? Heterosis refers to the phenomenon in which hybrid offspring exhibit characteristics that lie outside the range of the parents. This was initially described in 1908 by George Shull. You'll often hear the term hybrid vigor and heterosis used interchangeably. Heterosis is a phenomena that was formally described by George Shull when inbred lines were crossed. But this phenomena can be observed any time two related individuals are crossed or two unrelated individuals are crossed. The two pictures on this page show examples of heterosis in maize. The picture on the left shows four ears of corn. The ears of corn on the far left and far right of this image are from the inbred lines B73 and Missouri 17. These are two commonly used lines of corn. The ears in the middle are F1s. They are the result of crossing together B73 and Missouri 17. You'll notice that the F1 ears are substantially larger and have more seeds than either parent. Similarly, you can see hybrid vigor for plant growth characteristics in the picture on the right. Once again, the two parents are shown growing on the two edges of this image, and the rows in the middle are F1s. You'll see that the F1s have grown faster and result in more vigorous plants then either parent.