It is not unusual for daylily hybridizers to assume that cold stratification involves storing seeds dry in cool conditions. The assumption is not correct if the desire is to break seed dormancy since that involves cool moist conditions.
bobjax said:(However, I strongly feel that Cold Stratification applies to seeds from Dormant type plants.)
If seed dormancy in daylilies (cold moist stratification) applied only to seeds from dormant plants then it would be an inherited characteristic. However, characteristics are typically determined by the action of inheritance plus environment plus the interaction of inheritance with environment. To be determined by dormant type plants it would have to be purely inheritance.
One assumption about seed dormancy is that it prevents seeds that are mature from germinating late in the growing season. If they do so then they may not be able to grow large enough and store enough nutrients to survive until the next growing season.
As such it is basically a response of the seed to the environment that it experiences during the time that it develops on the pod plant. That can also include the environment that the pod parent experiences even before it starts to produce its flowers.
In a typical species seed dormancy or the lack of it can be an inherited characteristic since each species may have evolved to respond to a specific set of conditions. However, there are several important modifiers to the simple inheritance of seed dormancy.
One is that some species are present in many different locations with different climates and so seed dormancy may be advantageous in some parts of their home ranges and possibly disadvantageous in other parts. In such species seed dormancy may be strongly affected by the environment the seed experiences while developing.
The other applies to daylilies. The daylily gene pool or population is not derived from one species. It is derived from a mixture of a substantial number of species that have home ranges over wide areas. So it is quite possible that seed dormancy in daylilies is strongly affected by the environment that the seed experiences while developing.
As far as I know, no one has done the necessary test for daylilies. That would be to cross two cultivars in one environment where it would be advantageous for seeds to be dormant when they mature in the autumn. The same cross would need to be done in a different environment where it would not be advantageous for the seeds to be dormant when they mature in the autumn. Note, if the seeds mature at different times of the year/(growing season) that may be all that is required for the seeds to have more seed dormancy in one location than the other or for more of the seeds to be dormant in one location than the other.
A seed that matures late in a growing season has less time to grow and store resources than a seed that matures early in the same growing season. That in itself may be enough to change the probability that a seed will be dormant. A seed that matures late in a short growing season is likely to have a different probability of being dormant than a seed that matures early in a long growing season.
From one research publication,
"The environmental conditions experienced by plants during
seed development, known as the parental (or maternal) environment,
can influence seed dormancy in many species, and
thus seed dormancy is a plastic trait (Roach and Wulff,
1987; Donohue, 2009). When a seed is freshly mature, the
primary dormancy it displays developed while the seed
was maturing on the parent plant (Finch-Savage and
Leubner-Metzger, 2006; Donohue, 2009). During seed development,
maternal processes supply the seed with nutrients,
hormones, proteins and transcripts, which will influence the
seed's metabolism and gene expression (Donohue, 2009).
These processes can be regulated by environmental factors
such as photoperiod, temperature, water availability, vegetative
canopy development and nutrient supply (Fenner, 1991;
Gutterman, 2000; Donohue, 2009). The effect of a parental
environment factor may depend on the degree of stress that a
particular plant perceives. In particular, the effects of parental
photoperiod and temperature on dormancy show trends that are
consistent among a range of species, with seeds that develop in
a warmer environment or with shorter days often being less
dormant (Fenner, 1991; Gutterman, 2000; Donohue, 2009).
The effect of parental water supply is not as clear
(Gutterman, 2000); the majority of studies show that seeds
that develop with a lower water supply are less dormant (e.g.
Arnold et al., 1992; Meyer and Allen, 1999; Luzuriaga
et al., 2006). However, other studies have shown no effect
(Swain et al., 2006; Hoyle et al., 2008a, b) or even an increase
in dormancy (Sharif-Zadeh and Murdoch, 2000)."
From "Parental environment changes the dormancy state and karrikinolide response of Brassica tournefortii seeds" in Annals of Botany, Volume 109, Issue 7, June 2012, Pages 1369–1378
