Why hybrids sometimes/often loose disease resistance

General Discussion
1

This could be in the “Breeding Yellow Rugosas” thread but I have decided to start a new thread. Particularly with rugosa/non rugosa crosses a common comment has been that the parents were both disease resistant but the offspring are not. Often this is treated as a fact to accept with no attempt to explain why this happens.

The following link leads to an abstract of a paper which investigates this behavior. (I have the full paper. I can distribute a limited number of copies for educational use. If you are interested, please e-mail me.) Of particular interest to me is that the inefficiency of having 2 different pathways for the immune systems contributed from the parents is less important at high temperatures. Thus a hybrid may be fungus or aphid resistent at high temperature but less so in a cool climate.

The link is too long and ruins the formatting when placed in the “Page link” box. Here it is with spaces inserted. After a copy and paste you will have to remove the spaces.

http://www.sciencedirect.com/science? _ob=ArticleURL&_udi=B6VS4-5049JJM-2&_user=10&_coverDate=08%2F01% 2F2010&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort

=d&_docanchor=&view=c&_searchStrId=1657753956&_rerunOrigin=scholar.

google&_acct=C000050221&_version=1&_urlVersion=0&_use

rid=10&md5=a789a1aa0c16e61c2b761f44a43db8a0&searchtype=a

2

Henry, tried all sorts of space removals–no luck. Maybe if you define what a space is… Tried removing %20 and _.

Peter

3

Peter,

The first space was immediately after science? (1 space ) and the second space was in the second line after F01% (1 space) and I don’t believe there was another, but I was able to bring up the article.

4

Thanks, Jackie, that did it. I guess I took out too many spaces.

Peter

5

Very interesting paper. Thanks Henry.

Introducing and conclusions first words:

"Natural plant hybrid zones have been described as