Effect of daylength, light intensity and temperature on growth and flowering in roses

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Karl K
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Effect of daylength, light intensity and temperature on growth and flowering in roses

Post: # 69086Post Karl K
Wed Jan 23, 2019 12:45 am

Journal of the American Society for Horticultural Science 97: 796–800. (1972)
Effect of daylength, light intensity and temperature on growth and flowering in roses.
Roar Moe

Increasing the daylength (from 8 to 16 or 24 h) inhibited budbreak in glasshouse roses, whereas high temperatures (21 or 27 deg compared with 15 deg C) hastened it. The initiation of flowering was promoted by high light intensity and by long days. The effect of daylength was temperature dependent. At low temperatures rose shoots differentiated more leaves before flower initiation with short days than with long days, whereas at high temperatures there was no appreciable difference between daylength responses. The rate of shoot growth was stimulated by long days and high temperatures. The final length of shoots at flowering was considerably greater with 16-h days than with shorter days, but increasing temperature and light intensity both decreased eventual shoot length. The growth of the uppermost internodes, and especially the neck of the flower shoot, was most sensitive to daylength, temperature and light intensity. The number of days from the time of cutting-back until flowering was reduced by increasing daylength, temperature and light intensity.

This is an old paper, but it suggests some of the rather cryptic differences between cultivars that may contribute to "hybrid vigor".

The abstract of Moe's paper does not tell us how many cultivars were studied. This is important to know, because Greeley (1919) found that the optimum growing temperature varied from cultivar to cultivar. No doubt there would also be differences in the responses to varying daylength and light intensity. And when we look at species, the differences will be even more striking.
http://bulbnrose.x10.mx/Roses/breeding/ ... y1919.html

chuckp
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Re: Effect of daylength, light intensity and temperature on growth and flowering in roses

Post: # 69087Post chuckp
Wed Jan 23, 2019 12:13 pm

Hi Karl,
Can you please explain in layman's terms how and why Warren Millington can get such great results using Canadian breed roses
like Therese Bugnet,(as posted on FB). TB doesn't thrive, and hardly flowers or set hips for me here in the Manitoba. For a long time, I thought TB was sterile. Until I saw a plant covered with hips in Nova Scotia, four years ago.
I would be delighted to hear how TB does in other parts of the world.

Karl K
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Re: Effect of daylength, light intensity and temperature on growth and flowering in roses

Post: # 69088Post Karl K
Wed Jan 23, 2019 3:13 pm

ChuckP,
I don't have nearly enough information. How do the climate and soil differ between Manitoba and Nova Scotia? I haven't been to either province, and I have not seen 'Therese Bugnet'.

It would be helpful if other people in the north (and not so north) would weigh in on their successes/failures with 'Therese Bugnet'.

Karl

mntlover
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Re: Effect of daylength, light intensity and temperature on growth and flowering in roses

Post: # 69095Post mntlover
Wed Jan 23, 2019 10:15 pm

Therese Bugnet has grown well (bloomed well) for me, both in the Midwest (U.S.) and now in the inland pacific northwest. I did not try breeding with it in the midwest, but so far have been able to get seedlings from it here in north central Washington. Oddly, the first bush I have grew here for six years before setting a hip, only to start setting hips the last few years. I have two other bushes I only put in a couple seasons ago and they are both setting hips, so I don't think it was a matter of age. Weather conditions influencing it? All three bushes set OP hips this year. I put pollen on two bushes (testing about a dozen different pollens). I only had hip set with one: Mary Rose. Oddly I used Theresa Bugnet pollen on other bushes and it didn't set well either, although they set hips with other pollens.

In short I have gotten hip set with crosses, but picky. Lots of OP hips, wish I could figure out where the pollen was coming from that is working so well. I'm wondering if it is from wild roses up the hillside, as there are bushes spread out all over the hillside.

Seed germination was good on other years. This year it hasn't started yet, though I saw one seed cracking open, so hopefully the ball is about to get rolling.
Also, I have found much better hip set on the seedlings I grew from her than Therese herself: so it may be easier moving forward depending on which direction you wish to travel (diploid or not).

Duane

Karl K
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Re: Effect of daylength, light intensity and temperature on growth and flowering in roses

Post: # 69251Post Karl K
Fri Feb 08, 2019 2:39 pm

Another matter has come to my attention again that might be useful.

Pollen tubes are living things. Teeny tiny plants with genes, functions and preferences of their own. Furthermore, there is around a 67% overlap between genes active in the pollen tube and those active in the sporophyte (e.g., the plant). Therefore, it is possible in varying degrees to impose environmental conditions on the pollen tubes during their short lives that we want to have expressed in the plants.

In other words, pollination at low temperatures favors the growth of pollen tubes carrying genes that favor growth at low temperatures. This was demonstrated by pollinating tomato blossoms with a mixture of pollen from an ordinary tomato, and an accession of Lypersicon hirsutum collected at an altitude of 3200m. That's high, and that's cold. The result was that twice as many hybrids were formed at 12/6°C as compared to crosses with the same mixtures at 24/19°C.
http://bulbnrose.x10.mx/Tomato/ZamirTom ... n1981.html

We should also expect variation within a species, race or strain.
"Here, we have used peach to evaluate the effect of temperature on some processes of the progamic phase, from pollination to the arrival of pollen tubes in the ovary. Within the range of temperatures studied, 20°C in the laboratory and, on average, 5.7°C in the field, the results show an accelerating effect of increasing temperature on pollen germination and pollen tube growth kinetics, as well as an increase in the number of pollen tubes that reach the style base."
The underlined phrase suggests that some of the pollen tubes are more cold tolerant than others. It remains to be seen whether pollination at lower temperatures would yield peach trees that are also more cold tolerant. Or at least more able to be pollinated at lower temperatures.
http://bulbnrose.x10.mx/Heredity/Prunus ... n2005.html
Karl

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