Search found 398 matches

by Larry Davis
Tue Jan 28, 2020 11:44 pm
Forum: Rose Hybridizers Association Forum
Topic: Petite Knock Out Rose - AVOID
Replies: 20
Views: 412

Re: Petite Knock Out Rose - AVOID

These days, DNA techniques are so cheap that you don't really need a specific single gene to tag. Just compare a bunch of markers on several chromosomes that represent the haplotype (particular arrangement of different alleles in this cultivar). Works exactly like the DNA database that the govt uses...
by Larry Davis
Mon Jan 27, 2020 10:31 am
Forum: Rose Hybridizers Association Forum
Topic: Worms eating seeds
Replies: 15
Views: 231

Re: Worms eating seeds

I just looked up the enchytraiedae and find that they are called potworms. They are like miniature earthworms. They eat decomposing plant material in pots in greenhouses among other places. Maybe also California pot too.
by Larry Davis
Mon Jan 27, 2020 10:27 am
Forum: Rose Hybridizers Association Forum
Topic: Worms eating seeds
Replies: 15
Views: 231

Re: Worms eating seeds

I forwarded Joe's photo to our nematode specialist in Plant Pathology. He says they are too large to be plant/soil nematodes. Gnat larvae is the most likely guess though he mentions a family I never heard of or even now how to say ( enchytraeidae) as a possibility. There are larger nematodes but the...
by Larry Davis
Sun Jan 19, 2020 10:33 pm
Forum: Rose Hybridizers Association Forum
Topic: Germinating seeds
Replies: 5
Views: 107

Re: Germinating seeds

I tried a post earlier but it disappeared. Look on the home page for RHA, under publications. You will find a review that I wrote in 2010. It cites Tincker, at Wisley in the 1930s burying seeds in pots of damp stuff for the winter to vernalize and getting good germination when he took them out and p...
by Larry Davis
Sat Jan 18, 2020 11:23 pm
Forum: Rose Hybridizers Association Forum
Topic: tracking seed germination
Replies: 3
Views: 81

Re: tracking seed germination

Sorry, had to go for supper before finishing that one. Rushed a bit too. What happened with R. canina seems to be that there is a critical stage of ripeness when they germinated fairly fact and very well. Too early, or too late and they are much harder to get to sprout. I the UK this was studied dec...
by Larry Davis
Sat Jan 18, 2020 7:20 pm
Forum: Rose Hybridizers Association Forum
Topic: tracking seed germination
Replies: 3
Views: 81

Re: tracking seed germination

AS I recall, the original observations by Risley were for looking at just one parent, pollinated with a range of donors. He was interested in noting that whatever regulates germination, the pollen donor introduces something (presumably genes but possibly methylation patterns) that affect the product...
by Larry Davis
Wed Jan 15, 2020 8:48 pm
Forum: Rose Hybridizers Association Forum
Topic: Is every rose seed completely unique?
Replies: 17
Views: 231

Re: Is every rose seed completely unique?

In roses the base number for chromosomes is 7. That would be a haploid if it survived. Haploid means half of the pair. So a diploid has 7 pairs = 14 total. Those are usually fertile, and quite a few species, and some cultivated roses such as polyanthas often are diploid. More commonly among the hybr...
by Larry Davis
Mon Jan 13, 2020 11:58 pm
Forum: Rose Hybridizers Association Forum
Topic: What is the easiest and hardest steps in rose breeding?
Replies: 29
Views: 407

Re: What is the easiest and hardest steps in rose breeding?

Pollination is not that hard. I'm lazy, so I just rip off the petals and stamens, unless I want their pollen. then I collect them in a plastic petri dish and pitch the petals. I use 25 or so colors of plastic tagging tape to represent pollen parents. I make a list to carry with me. tie the tape arou...
by Larry Davis
Sun Jan 05, 2020 3:07 pm
Forum: Rose Hybridizers Association Forum
Topic: non rose plant from Zlesak
Replies: 9
Views: 183

Re: non rose plant from Zlesak

If a mutation in FLC is the cause of blooming on new wood, it generally doesn't depend much on either daylength or vernalization, in the Rosaceae. Of course there are roses that vary a lot in their reblooming propensities. I notice that no matter what I do, in terms of water, fertilizer and location...
by Larry Davis
Sat Jan 04, 2020 2:57 pm
Forum: Rose Hybridizers Association Forum
Topic: non rose plant from Zlesak
Replies: 9
Views: 183

Re: non rose plant from Zlesak

The colorful ninebark is very attractive and two plants did well for me in pots this past summer, courtesy of David Z. But one thing puzzles me. The plants arrived with the remnants of early spring bloom despite their height of under 1 ft. They grew and grew many shoots to perhaps 2 ft by frost time...
by Larry Davis
Mon Dec 16, 2019 11:31 pm
Forum: Rose Hybridizers Association Forum
Topic: R. carolina video
Replies: 17
Views: 515

Re: R. carolina video

That is a great video of great plants. I wonder if fertility and soil tilth plays a role in the difference between woodsii in CO and MN? Some sedimentary sandy soils are phenomenal for nursery stock. Here in town daylilies grow twice as fast in a fine silt loam of a community garden as they do up on...
by Larry Davis
Fri Dec 06, 2019 8:42 pm
Forum: Rose Hybridizers Association Forum
Topic: Rose Breeding Texas A and M
Replies: 2
Views: 172

Re: Rose Breeding Texas A and M

Thank you Henry. Very interesting. I hadn't heard that both palustris and setigera are thought to be resistant to RRD. This summer I challenged setigera. I guess next year I need to try palustris.
by Larry Davis
Mon Nov 04, 2019 9:07 pm
Forum: Rose Hybridizers Association Forum
Topic: Odd little seedling
Replies: 12
Views: 550

Re: Odd little seedling

Here's a thought that might pique Karl's interest. Dwarfing of apples, pears and the like depends on rootstock, or interstock grafting. Is there any evidence in he rose literature for such things? I only know the examples of minatures grafted onto standards where you get a small bush on top of a lon...
by Larry Davis
Tue Oct 22, 2019 11:35 pm
Forum: Rose Hybridizers Association Forum
Topic: Question about seed ripening and pollen parent
Replies: 16
Views: 1196

Re: Question about seed ripening and pollen parent

I've observed that R pomifera tends to have effect of early ripening in hips for which it is the pollen parent, just as it ripens incredibly fast as a mother, around 2 mo. Probably there is a species effect, but once you mix a few you can really only talk of cultivars. We don't really know the % of ...
by Larry Davis
Tue Oct 22, 2019 9:35 pm
Forum: Rose Hybridizers Association Forum
Topic: Question about seed ripening and pollen parent
Replies: 16
Views: 1196

Re: Question about seed ripening and pollen parent

I don't recall ever reading a paper that discusses a pollen effect on seed production/ripening time. But back in the 1950s it was shown by a breeder (in NH?) that the male parent determined time to germination. One mother, several different pollens, average days to germ varied widely. Karl has the p...
by Larry Davis
Fri Oct 11, 2019 11:15 pm
Forum: Rose Hybridizers Association Forum
Topic: Newbie question
Replies: 12
Views: 875

Re: Newbie question

Henry is most certainly correct. So is Don. On the RHA website is a long review I wrote on all the germination papers I could find in about 2014. No big breakthroughs since. Some species have an optimum harvest time. For instance decades ago R canina germinated best at a certain stage of red, fully ...
by Larry Davis
Fri Sep 20, 2019 10:38 pm
Forum: Rose Hybridizers Association Forum
Topic: Newbie question
Replies: 12
Views: 875

Re: Newbie question

About hip picking in autumn. A couple years ago (fall 2017) I had access to a bunch of OP hips on two plants of a yellow HT/grandiflora of uncertain parentage but rather like Julia child. I knew that they had set at midsummer or later but a hard frost was coming. So I cut them off long with leaves s...
by Larry Davis
Sun Aug 25, 2019 3:58 pm
Forum: Rose Hybridizers Association Forum
Topic: Non-fading suggestions
Replies: 11
Views: 662

Re: Non-fading suggestions

First Impression, by Jim Sproul has given me very saturated yellows that last. Not very winter hardy at 0 F or below and will get blackspot if there is any in town. But I've crossed it to get some very good yellows that don't have BS. It resists mildew and can improve it's partner's performance. For...
by Larry Davis
Mon Aug 12, 2019 11:05 pm
Forum: Rose Hybridizers Association Forum
Topic: Lac Majeau x John Cabot
Replies: 2
Views: 240

Re: Lac Majeau x John Cabot

That looks a potentially very interesting rose. Love to see a later bloom which may be even more double and larger.
by Larry Davis
Mon Jul 29, 2019 10:17 pm
Forum: Rose Hybridizers Association Forum
Topic: Why some crosses fail
Replies: 11
Views: 823

Re: Why some crosses fail

I can't say a lot about why crosses fail other than plant incompatibility but about Therese Bugnet there is something odd going on in my experience. AT my house it competes with roots a a neighbor's maple tree and gets enough supplementary water to keep it growing. But it neve gets above 5 ft tall, ...