Another possible route to haploids?

General Discussion
1

Yesterday I went to a farmer’s seed store, and they had another hormone product for bloom set. It is called “Bonide Fruit Set Spray”. The active ingredient is 0.005 % p-Chlorophenoxyacetic Acid. It comes as an 8 ounce hand push spray bottle and costs $3.99.

So today I did a computer literature search to see what I could find concerning its use as a fruit set hormone. I did find some non rose papers; but the paper that may be the most important is the following:

Title: A NOVEL APPROACH TO DIFFERENTIATED EMBRYOS IN THE ABSENCE OF ENDOSPERM

Author: MATZK F

Author affiliation: INST GENETIK KULTURPFLANZENFORSCHUNG, 0-4325 GATERSLEBEN, WEST GERMANY.

Published in: Sexual Plant Reproduction, volumn 4, pages 88-94, (1991).

Abstract: " In all of the Poaceae tested (Bromus, Festuca, Hordeum, Lolium, Poa, Triticum) the formation of grains without endosperm was induced from unpollinated ovules by treatment with the following synthetic auxins: DIC; 2,4-D; 2,4,5-T; or CPAA. Cytokinins (BAP, ZTN) as well as adenine or gibberellic acid (GA3) alone were ineffective. In parthenogenetic lines auxin treatment resulted in grains with mature embryos without endosperm. Differences in embryo differentiation were found, which were dependent on the synthetic auxins used, their concentrations, and the developmental stages of the treated spikes or panicles. Thus, the regulation of embryogenesis by the endosperm can be replaced by exogenous auxin application. The developing proembryos of grasses did not need nutritive support from the endosperm. Auxin treatment to give mature embryos without endosperm enables the screening of apomictic species for sexual plants and sexual species for parthenogenetic individuals. It opens ways for inducing haploid parthenogenesis and improves methods for overcoming interspecific crossing barriers."

I was not able to download the full paper; but the keywords did not use words like “vitro” so it does not appear that they are referring to tissue culture experiments but to actual on the plant spraying.

2

Hmm. Is the absorbancy (sp?) rate much higher in grasses than roses, though? In other words, what ratio would be a good educated guess for roses?

-Mike

3

Good point Jadae – monocots and dicots react quite differently to a lot of these artificial hormones (a fact that allows there to be herbicides that only kill broad leafed plants) so one might not be able to apply it to roses – but it would be worth a try. But the abstract says they develop without endosperm… Even though an embryo ca DEVELOP without the nutriative support of an endosperm, it wouldn’t be able to germinate, I wouldn’t think. So you would probably have to go to tissue culture techniques at some point.

But it certainly bears looking into more.

Joseph

4

Jadae, I assume that one could inject the hormone with a syringe.

5

I suppose. They sell 12cc syringes w/ needles at the feed store for animal meds. Sounds like a fun experient.

6

hah! great timing this morning. Lowe’s has the Bonide Fruit Set Spray on clearance for 1.50 if anyone is interested.