BGN 2: VIII. LETTERS TO THE EDITORS BARLEY GENETICS NEWSLETTER, VOL. 2, VIII. LETTERS TO THE EDITORS
Pages 201-202

I have two suggestions for the next Barley Newsletter. The description of your stock in Barley Genetic Newsletter No. 1 was very good but could we have an index? The second one is if we could have a list of new recombination units and planned investigations. I would suggest a list like this:

Should it be necessary to define Ha2, I will suggest the following description. The situation is much more complicated than shown in these few words, but I think that this would be sufficient.

The gene Ha1 is monofactorial dominant. It was found by Nilsson-Ehle (1920) and a definition was made by Andersen (1961). The gene is transferred from the variety Drost to many commercial varieties. The gene gives resistance to race 1 of Heterodera avenae. Larvae of race 1 cannot develop into white cysts in the roots of resistant plants.

The gene Ha2 is monfactorial dominant. It was found in our collection no. 191 (Andersen 1961) and is now transferred to many commercial varieties e.g. the variety Siri. The gene gives resistance to race 1 and 2 of Heterodera avenae. Larvae of these races of the nematode cannot develop into white cysts in the roots of resistant plants.

Sigurd Andersen
Royal Veterinary and
  Agricultural College
Copenhamnv, Denmark

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Precocious internodal elongation in uniculm (uc2 uc2) barley seedlings.

We have noted in this spring's field planting (1971) in uniculm seedlings from lines homozygous for the gene uc2, and selected for high yield, a different and more precocious type of internodal elongation than occurs in the normal tillering barley planted nearby at the same time.

There appears to be an energy shunt from normal tiller development to the extended development of one or more of the lower internodes, although tiller developement is not completely suppressed.

There are some indications that the development of the sub-crown internode may not be normal.

R. I. Wolfe
Barley Breeding
Research Station
Canada Department of Agriculture
Box 610
Brandon, Manitoba
Canada

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