How long to keep seedlings for evaluation?

My father-in-law is growing a seedling that is now a little over four years old. It is fairly healthy but otherwise completely un-noteworthy except for the fact that it is only now blooming for the first time. Isn’t that a bit old for a rose to finally begin blooming? Can I expect it to be non-repeating? Do some roses need to reach a certain maturity level before the blooming genes are expressed? If so, once they are “turned on” do they always stay on (hence bud grafts and cuttings continue to lead to quick blooming).

This worries me because I have discarded many healthy specimens that failed to bloom after two years.

Are there other traits I am missing out on because I have not waited long enough for their expression?

Having some place at hand, and doing only a limited number of seedlings a year, I usually “forget” apparently unworthwile seedlings “in a corner”.

There, they may choose to improve or to die.

I had one of these, flowering after some years (don’t remember how many) and recovering from a tendancy to BS, that satisfies me now. So it can happen! I named it “Let me never be composted”. It ressembles a dwarfed Hybrid Musk with dark pink China-like blooms.

I do not care at all about diseases, I see that as an acclimatation process only. But of course I never spray, and if the plant don’t manages the process for itself

it simply dies.

Best wishes,

Pierre Lauwers.

One of the Canadian Government hybridizing groups published a reviewed scientific paper concerning the year germination, amount of flowering situation.

From memory: those that bloomed for the first time in year 4 had similar amount of flowering data as those which first bloomed in earlier years. I think that I posted something about it here in the past and that it was reprinted in the RHA Newsletter.

Research concerning flowering period in crosses

Posted by Henry Kuska [email] on Mon, Sep 20, 2004

Felicitas Svejda published a paper in Euphytica, volumn 26, pages 697-701, (1977), “Breeding For Improvement of Flowering Attributes of Winterhardy Rosa Rugosa Hybrids”.

The following are some of the findings that I felt are particularily interesting:

  1. Among the 75 two year old seedlings there were only 11 “keepers” if the “keep” criteria was to keep only seedlings that had a flowering period of 12 to 16 weeks (the plants were observed for periods of from 13 to 16 weeks depending on the year). The third year, 26 seedlings had periods of bloom in that range. Thus, “keeper” selection after only two years would of resulted in throwing out 15 seedlings that would have been “keepers” if year three selection would have been used.

  2. Four of the seedlings still had not bloomed by the end of the second year. All third year seedlings had bloomed.

  3. Eleven seedlings were studied in detail concerning their flower production. The length of the flower production (in general) was not correlated with the number of flowers produced. However, the 4 seedlings with the longest flower production also produced the most flowers.

  4. Four seedlings had longer flower production periods than the longer flowering parent. Only one seedling had a shorter flower production period than the shorter flowering parent.

  5. Four seedlings produced a greater number of flowers than the more prolific parent. Five seedlings produced fewer flowers than the less prolific parent.


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Thanks Mr Kuska,

This tends to confirm the fact we need place above all else, in order to give a chance to a maximum of seedlings rather than “over-selecting” them on questionable criterias

(i.e. PM when 1 month old, not flowering the first season etc). I am sure we all have throwed valuable things on the compost pile.

Best wishes,

Pierre Lauwers.

I keep my seedlings until I see the first bloom.

Climbers and shrubs may take two to three years to show their first bloom.

In the eighties I had a seedling with R. Nutkana as pollen parent which took five years to show the first blooom and finally I could throw it away !!!

Out of 50 seedlings with Nutkana as pollen I kept a total of three which are now growing in the San Jose Heritage Rose Garden as :

Mander # 1, Mander # 2 & Mander # 3.

All three are also growing in Germany in the Rose Garden of Kassel-Wilhelmsh

Forgot to tell you about my "Kassel-Wilhelmsh

I have to admit that I am one of those who will throw out seedlings that don’t bloom in the first year. I do keep unusual crosses with species or near-species that do not bloom in the first year. But, crosses that involve modern roses must bloom early for me. I believe that healthy vigorous growing seedlings should bloom by the time the seedling has 7 to 10 true leaves. If it doesn’t, that suggests to me that the mature plant will probably be less floriferous. I have had some very pretty blooms on seedlings that were way to stingy on bloom production. These are not worth keeping and should not be used for further breeding.

Jim Sproul

In my humble opinion: desease resistance is a rarer feature than nice flower.

As I am breeding for desease resistance all my seedlings are kept for more than two years. This is the minimum time lapse I have determined as a necessity in order to assess desease resistance or tolerance for seedlings as for newly bought vars.

We have a strong desease pressure here french riviera with a very variable climate with at any time of the year strong rains and warm wet weeks as well as colder wet monthes where the prevailing desease strains are different that may and often do contaminate a var that had been imune so far. Here Sunsprite is a poor desease prone rose that succomb from blackspot in three years as I never spray. Baby Love although more tolerant has found its blackspot strain too.

As well (bad?) a new var or seedling need this period in order to “find” the desease strains able to contaminate it.

And yes an initialy very deseased seedling may be quite tolerant when not so young. There are some good points for this: one is less young foliage close to the ground, another is competition among the different desease strains.