jbergeson wrote:Such selfing would be very interesting, Jonathan. First of all, statistically there would be a tiny chance (when working with tetraploid moderns and species the chance should be around 2.7%) that the selfed seedlings would recombine to be rebloomers. Secondly, it would be fun to evaluate whether any hybrid vigor shown in the F1's would continue into the next generation. Third, it would just be fun to see how the genes segregated in the population of self-pollinated F1's.
Here is one example of selfing, though Nicolas did not give a full account of all the variations. It would have been nice if he had mentioned whether there were any rebloomers or doubles.
ARS Magazine, May-June, 1933
Hybridizing Species Roses
J. H. NICOLAS
Crosses of species roses and Hybrid Teas sometimes give strange results not always compatible—to the layman's eye —with the parents, but, apparently, they are to be expected when unrelated or distant types are cross-bred: A friend of mine [Schoener] sent me a hybrid reputed to be a cross of R. nutkana
and Paul Neyron, a shrubby, vigorous plant but without apparent trace of Nutkana, although the bloom was single and pink. As it excited a great deal of skepticism as to its true origin, I planted a handful of selfed seeds, and in the lot came several more or less Nutkana types, and one almost pure Nutkana in all particulars, even with its root-stolons traveling long distances. This experience satisfied the doubting Thomases—including myself.
Allard did give a few more details, noting that he got more singles than semi-doubles.
Jardins de France 1: 725 (1900)
Having harvested at different times of the fruits of Rosa harrisonii,
I planted the seeds and got a variety of roses with single flowers, white, pink, yellow and one semi-double flower, with the same color and tone as that of Rosa lutea
Miller. All are dwarf shrubs that run with the Rosa pimpinellifolia,
for the main characters: prickles, leaves, purple black fruit, etc.
The Rosa harrisonii
has also characters of Rosa pimpinellifolia,
but it is closer to Rosa lutea
in the color of the flower. However, it is considered by many rose growers as being a variety of this Rose. This would be, we believe, a hybrid of Rosa pimpinellifolia
crossed by R. lutea.
Some hybrids of R. wichuraiana
are available for further study. I have seen 'Glenn Dale', 'Francois Foucard', 'Paul Noel', 'Gardenia' and 'Francois Juranville'. Of these, the first two appeal to me more than the others.
'Francois Foucard' has lots of small petals, perhaps inherited from the Noisette parent of 'l'Ideal'. It blooms over a long period, and has a delicious perfume. 'Glenn Dale' has a shapely Tea-like form derived from 'Isabella Sprunt'. It is possible that selfing either, or crossing the two, could yield some hardy bushes with flowers more deeply colored than either. Or they could be crossed with well-formed HTs or Floribundas to give yellow-toned companions for 'New Dawn'.
Finally, it may be possible to "crack" species without breeding to garden roses. Crosses between geographically remote races, particularly involving naturally occurring variants, can give the breeder a leg up. R. arkansana,
for example, has produced a few double-flowered selections, as well as white-flowered and red-flowered forms. The double forms, 'John Allan' and 'Woodrow', are not identical. I don't know that anyone has tried crossing the two to give us some improved forms. And crossing these with the white- and red-flowered forms would give further improvement. THEN one could cross a double red Arkansana with a double red garden rose without worrying so much about singles and ordinary pinks turning up in the progeny.
A real-world example of this is (was) Burbank's 'Giant Maritima' plum. He started by domesticating the wild plum, selecting for improved size and sweetness for a few generations. He then mated a greatly improved Beach plum with a high quality Japanese plum. In the F2 generation he raised the largest plum he had ever seen ... and he was someone who really knew about plums.http://bulbnrose.x10.mx/Heredity/Burban ... a1914.html