Post by nicollas on Sept 3, 2013 8:39:40 GMT -5
Hi,
i came across a way of propagating JA/sunchokes i didnt know in Biology and Chemistry of Jerusalem Artichoke: Helianthus tuberosus by
Stanley J. Kays, Stephen F. Nottingham. Slip propagation is interesting when one has a few tubers from a new cultivar, as i excpect to get some tubers from the US next fall ... Maybe you will discover it too
Stem cuttings are also reported, but this method is discouraged (it may be usefull for amateur in some context ?)
And finally seeds, it may have some good tips from the members who test JA seed growing
i came across a way of propagating JA/sunchokes i didnt know in Biology and Chemistry of Jerusalem Artichoke: Helianthus tuberosus by
Stanley J. Kays, Stephen F. Nottingham. Slip propagation is interesting when one has a few tubers from a new cultivar, as i excpect to get some tubers from the US next fall ... Maybe you will discover it too
Slips (transplants), derived from sprouted tubers, can be used to increase the plant population of a
clone over what would be realized via direct field planting of the tubers. To obtain slips the tubers
are planted 4 to 6 cm deep in warm beds or within a greenhouse using standard potting media.
The tubers should be spaced such that they are not touching but otherwise tightly arranged.
Individual slips are harvested by carefully detaching them at the tuber when they are 20 to 30 cm
tall and have four or more fully expanded leaves. Less mature slips have few if any roots, have
small-diameter stems that are more likely to be broken or damaged, and grow more slowly than
larger, more robust slips. Smaller slips should be left for a subsequent harvest. The slips can not
be transplanted directly into the field without substantial losses and should first be placed in potting
media under mist for 10 to 12 days before transplanting into the field. Removal from the mist to
harden off for several days is recommended, especially if hot and dry conditions prevail during
field planting. The slips, therefore, are collected in a succession of harvests every 4 to 6 days; as
a consequence, it takes 4 to 5 weeks to produce the maximum number of slips plus additional time
for rooting.
The number of sprouts produced per tuber varies with tuber size; small tubers (i.e., 30 g)
produce fewer slips (~7) than larger tubers (50 to 70 g), which produce 13 to 15 plants each (Kays,
unpublished data). Generally the slips from the larger tubers have thicker stems, are more robust,
and are less inclined to droop. If the objective is to significantly increase the plant population,
direct planting of a “seed tuber” in the field results in only one plant, while approximately 15 plants
per tuber can be produced using slips. Slips may also be used for earlier field stand establishment;
however, the disadvantages of this method are sufficient that it is seldom used. For example, it
greatly increases labor costs, and the time interval required to obtain the maximum number of
sprouts per tuber significantly staggers the age of the stand in the field. However, when only a
small number of tubers of a cultivar are available and the objective is to increase the propagation
material for the following year, the use of slips is effective.
clone over what would be realized via direct field planting of the tubers. To obtain slips the tubers
are planted 4 to 6 cm deep in warm beds or within a greenhouse using standard potting media.
The tubers should be spaced such that they are not touching but otherwise tightly arranged.
Individual slips are harvested by carefully detaching them at the tuber when they are 20 to 30 cm
tall and have four or more fully expanded leaves. Less mature slips have few if any roots, have
small-diameter stems that are more likely to be broken or damaged, and grow more slowly than
larger, more robust slips. Smaller slips should be left for a subsequent harvest. The slips can not
be transplanted directly into the field without substantial losses and should first be placed in potting
media under mist for 10 to 12 days before transplanting into the field. Removal from the mist to
harden off for several days is recommended, especially if hot and dry conditions prevail during
field planting. The slips, therefore, are collected in a succession of harvests every 4 to 6 days; as
a consequence, it takes 4 to 5 weeks to produce the maximum number of slips plus additional time
for rooting.
The number of sprouts produced per tuber varies with tuber size; small tubers (i.e., 30 g)
produce fewer slips (~7) than larger tubers (50 to 70 g), which produce 13 to 15 plants each (Kays,
unpublished data). Generally the slips from the larger tubers have thicker stems, are more robust,
and are less inclined to droop. If the objective is to significantly increase the plant population,
direct planting of a “seed tuber” in the field results in only one plant, while approximately 15 plants
per tuber can be produced using slips. Slips may also be used for earlier field stand establishment;
however, the disadvantages of this method are sufficient that it is seldom used. For example, it
greatly increases labor costs, and the time interval required to obtain the maximum number of
sprouts per tuber significantly staggers the age of the stand in the field. However, when only a
small number of tubers of a cultivar are available and the objective is to increase the propagation
material for the following year, the use of slips is effective.
Stem cuttings are also reported, but this method is discouraged (it may be usefull for amateur in some context ?)
Stem cuttings from several Helianthus species (e.g., H. tomentosum Michx., H. debilis Nutt.) can
be readily rooted under appropriate conditions (Norcini and Aldrich, 2000; Phillips, 1985). A
number of studies have also been conducted using H. annuus hypocotyls as a rooting model (Liu
et al., 1995; Wample and Reid, 1979), though they have only limited relevance to rooting stem
cuttings. While stem cuttings do not represent a normal reproductive mechanism for Helianthus,
they can be used to rapidly expand clonal material when seeds are not available. For H. debilis,
best results were obtained using subapical cuttings trimmed to distal leaves and rooted in a well-
drained medium with frequent misting (e.g., 9 sec/2.5 min) and under partial shade (i.e., 30%
shade) (Norcini and Aldrich, 2000). Survival was best without the use of a rooting hormone (1 H-
indole-3-butyric acid solution). Nontreated cuttings had 100% survival and were sufficiently rooted
for transplanting in 17 to 21 days. For both H. tomentosum (Phillips, 1985) and H. debilis, a well-
drained medium is desirable (e.g., sand and peat moss, 3:1).
The potential of using stem cuttings for the propagation of H. tuberosus was tested (single
clone; Kays, unpublished data). Cuttings of two lengths (15 and 25 cm), two stem diameters
(medium and large), two positions (apical and subapical), and with and without hormone (100 ppm
IBA talc) were placed in an artificial medium (2:1 perlite and peat moss) under mist and evaluated
(1 to 5 rating) after 45 days. All cuttings rooted. However, there was considerable variation in the
number of roots formed within and between treatments. Propagation of Jerusalem artichoke via
stem cuttings does not appear to be a viable option for two reasons: (1) the time required for the
stock plants to attain a sufficient size for cuttings plus the time required for rooting of the cuttings
would make the production season too short for most locations, and (2) plants derived from rooted
cuttings produced few tubers. The latter problem appears to be due to the fact that rhizomes normally
arise from the underground portion of the stem and not the roots. They seldom formed on the
underground portion of the rooted aerial stems, though the potential to do so may vary among clones.
be readily rooted under appropriate conditions (Norcini and Aldrich, 2000; Phillips, 1985). A
number of studies have also been conducted using H. annuus hypocotyls as a rooting model (Liu
et al., 1995; Wample and Reid, 1979), though they have only limited relevance to rooting stem
cuttings. While stem cuttings do not represent a normal reproductive mechanism for Helianthus,
they can be used to rapidly expand clonal material when seeds are not available. For H. debilis,
best results were obtained using subapical cuttings trimmed to distal leaves and rooted in a well-
drained medium with frequent misting (e.g., 9 sec/2.5 min) and under partial shade (i.e., 30%
shade) (Norcini and Aldrich, 2000). Survival was best without the use of a rooting hormone (1 H-
indole-3-butyric acid solution). Nontreated cuttings had 100% survival and were sufficiently rooted
for transplanting in 17 to 21 days. For both H. tomentosum (Phillips, 1985) and H. debilis, a well-
drained medium is desirable (e.g., sand and peat moss, 3:1).
The potential of using stem cuttings for the propagation of H. tuberosus was tested (single
clone; Kays, unpublished data). Cuttings of two lengths (15 and 25 cm), two stem diameters
(medium and large), two positions (apical and subapical), and with and without hormone (100 ppm
IBA talc) were placed in an artificial medium (2:1 perlite and peat moss) under mist and evaluated
(1 to 5 rating) after 45 days. All cuttings rooted. However, there was considerable variation in the
number of roots formed within and between treatments. Propagation of Jerusalem artichoke via
stem cuttings does not appear to be a viable option for two reasons: (1) the time required for the
stock plants to attain a sufficient size for cuttings plus the time required for rooting of the cuttings
would make the production season too short for most locations, and (2) plants derived from rooted
cuttings produced few tubers. The latter problem appears to be due to the fact that rhizomes normally
arise from the underground portion of the stem and not the roots. They seldom formed on the
underground portion of the rooted aerial stems, though the potential to do so may vary among clones.
And finally seeds, it may have some good tips from the members who test JA seed growing
Seed reproduction is important in wild populations and is an essential part of Jerusalem artichoke
plant breeding programs. Jerusalem artichoke is an obligate outcrosser that exhibits a high level of
self-incompatibility (Toxopeus, 1991; van de Sande Bakhuyzen and Wittenrood, 1950). Plants do,
however, readily outcross with other clones and produce seed (Swanton and Cavers, 1989; Le
Cochec, 1985). The seeds are considerably reduced in size compared to cultivated sunflower and,
in general, have a substantially lower germination rate. Mature seeds also display a strong dormancy
that can be suppressed with various treatments (Toxopeus, 1991).
Seed yield per plant varies widely with genotype, location, and production conditions. Wild
populations tend to flower more and have higher achene viability than cultivated clones (Westley,
1993). In general, low seed production for the species may be in part related to the late flowering
and cooler temperatures in the fall. The number of seeds per flower, number of seeds per plant,
and mean seed size of six clones representing three ecotypes (two cultivated, two weedy, and two
wild) varied substantially (Swanton, 1986). Weedy clones produced ~5 seeds per flower while the
cultivated clones had from 0.08 to 2 seeds. Variation in the mean seed weight among clones was
relatively small (3.5 to 4.8 mg), though individual seed weights ranged from 0.8 to 10.8 mg. The
number of seeds per plant varied from 5.6 to 78. In contrast, the seed yield from five commercial
cultivars allowed to outcross ranged from 88 to 1,058 seeds per plant (Lim and Lee, 1989).
A common problem in a number of wild Helianthus species is the presence of a seed coat
dormancy mechanism. Though at a much lower level, some inhibition can also be seen in cultivated
sunflowers. Kamar and Sastry (1974) found that 20-day-old seeds had a substantially higher
germination than did more mature seeds (i.e., 30 and 40 days old), indicating the presence of a
dormancy mechanism. The onset of dormancy early in seed development is typical of many seed
bearing species in that it prevents premature germination (vivipary) during development (Kays and
Paull, 2004). Seed dormancy of varying levels is found in all of the wild species of Helianthus but
is particularly strong in the annual desert species H. deserticola Heiser, H. anomalus Blake, and
H. niveus ssp. tephrodes (A. Gray) Heiser (Heiser et al., 1969).
Several methods to facilitate germination have been tested, such as planting the seed in pots
that are placed outside during the winter for 3 to 4 weeks, where they are exposed to varying
temperatures and freezing and thawing (Heiser et al., 1969). While germination improved, it was
seldom over 50% and was not effective for xerophytic annual species. Chemical treatment of the
seed with 2-chloroethyl phosphonic acid, an ethylene-releasing compound (Kamar and Sastry, 1974,
1975; Zimmerman, 1977), gibberellic acid (GA3), and benzyladenine (Kamar and Sastry, 1974,
1975) has been shown to increase the germination of freshly harvested, cultivated sunflower seed.
Likewise, dehulling facilitates germination (Harada, 1982; Kamar and Sastry, 1974, 1975). Tests
on four difficult-to-germinate species (H. bolanderi A. Gary, H. petiolaris Nutt., H. anomalus, and
H. niveus ssp. tephrodes) showed that the single most effective treatment was to remove the hull
and seed coat (i.e., 90% germination) (Chandler and Jan, 1985). This could be improved with
additional treatments (i.e., mechanical scarification, a 1-h soak in a 100 mg·l–1 solution of GA3,
and hull removal). Jerusalem artichoke seed germination is also substantially improved with the
removal of the seed coat (Lim and Lee, 1990).
The following technique, utilizing sterile conditions at each step, is routinely used for facilitating
the germination of wild Helianthus species (Seiler, personal communication). The seeds are first
surface sterilized for 15 to 20 min using a 1% (w/v) solution of sodium hypochlorite, rinsed with
distilled water, and then scarified by cutting a small portion of the seed coat from the wide end of
the seed. The seeds are then treated with GA3 at 100 mg·l–1 in distilled water for 1 h and subsequently
placed on moist filter paper in a petri dish and held in the dark overnight (21°C). The following
day the seed coat is carefully removed and the seedling rinsed with water, placed in a new petri
dish with moist filter paper, and returned to dark storage for 2 days. A fungicide such as benomyl
can be used to reduce the possibility of fungi contamination. After 2 days, the petri dishes are
placed under fluorescent lighting until the seedlings are of sufficient size for transplanting.
Jerusalem artichoke seeds are not used as reproductive propagules for commercial production
of the crop since the plants have relatively high levels of male sterility and incompatibility and the
seed, when present, generally represents crosses between the mother plant and an unknown pollen
donor. Thus, the genetic makeup of the seed is unknown, and with many polyploid species, the
propensity for the offspring to be superior to the parent lines is generally extremely low. For
example, from around 8,000 seedlings in a Jerusalem artichoke breeding program, only 17 were
saved for evaluation from clonal material in the subsequent year (Mesken, 1988). In addition,
Jerusalem artichokes derived from seed typically are less vigorous than the plants emerging from
tubers. Hence, plants from tubers grow much more rapidly and establish a closed canopy more
quickly. Finally, Jerusalem artichoke seeds typically have a low germination rate, decreasing their
potential utility as a commercial means of propagation. Thus, while there have been occasional
reports of successful production of the crop from seed (Lim and Lee, 1990), the potential of seed
at this point in the genetic manipulation of the crop remains remote.
plant breeding programs. Jerusalem artichoke is an obligate outcrosser that exhibits a high level of
self-incompatibility (Toxopeus, 1991; van de Sande Bakhuyzen and Wittenrood, 1950). Plants do,
however, readily outcross with other clones and produce seed (Swanton and Cavers, 1989; Le
Cochec, 1985). The seeds are considerably reduced in size compared to cultivated sunflower and,
in general, have a substantially lower germination rate. Mature seeds also display a strong dormancy
that can be suppressed with various treatments (Toxopeus, 1991).
Seed yield per plant varies widely with genotype, location, and production conditions. Wild
populations tend to flower more and have higher achene viability than cultivated clones (Westley,
1993). In general, low seed production for the species may be in part related to the late flowering
and cooler temperatures in the fall. The number of seeds per flower, number of seeds per plant,
and mean seed size of six clones representing three ecotypes (two cultivated, two weedy, and two
wild) varied substantially (Swanton, 1986). Weedy clones produced ~5 seeds per flower while the
cultivated clones had from 0.08 to 2 seeds. Variation in the mean seed weight among clones was
relatively small (3.5 to 4.8 mg), though individual seed weights ranged from 0.8 to 10.8 mg. The
number of seeds per plant varied from 5.6 to 78. In contrast, the seed yield from five commercial
cultivars allowed to outcross ranged from 88 to 1,058 seeds per plant (Lim and Lee, 1989).
A common problem in a number of wild Helianthus species is the presence of a seed coat
dormancy mechanism. Though at a much lower level, some inhibition can also be seen in cultivated
sunflowers. Kamar and Sastry (1974) found that 20-day-old seeds had a substantially higher
germination than did more mature seeds (i.e., 30 and 40 days old), indicating the presence of a
dormancy mechanism. The onset of dormancy early in seed development is typical of many seed
bearing species in that it prevents premature germination (vivipary) during development (Kays and
Paull, 2004). Seed dormancy of varying levels is found in all of the wild species of Helianthus but
is particularly strong in the annual desert species H. deserticola Heiser, H. anomalus Blake, and
H. niveus ssp. tephrodes (A. Gray) Heiser (Heiser et al., 1969).
Several methods to facilitate germination have been tested, such as planting the seed in pots
that are placed outside during the winter for 3 to 4 weeks, where they are exposed to varying
temperatures and freezing and thawing (Heiser et al., 1969). While germination improved, it was
seldom over 50% and was not effective for xerophytic annual species. Chemical treatment of the
seed with 2-chloroethyl phosphonic acid, an ethylene-releasing compound (Kamar and Sastry, 1974,
1975; Zimmerman, 1977), gibberellic acid (GA3), and benzyladenine (Kamar and Sastry, 1974,
1975) has been shown to increase the germination of freshly harvested, cultivated sunflower seed.
Likewise, dehulling facilitates germination (Harada, 1982; Kamar and Sastry, 1974, 1975). Tests
on four difficult-to-germinate species (H. bolanderi A. Gary, H. petiolaris Nutt., H. anomalus, and
H. niveus ssp. tephrodes) showed that the single most effective treatment was to remove the hull
and seed coat (i.e., 90% germination) (Chandler and Jan, 1985). This could be improved with
additional treatments (i.e., mechanical scarification, a 1-h soak in a 100 mg·l–1 solution of GA3,
and hull removal). Jerusalem artichoke seed germination is also substantially improved with the
removal of the seed coat (Lim and Lee, 1990).
The following technique, utilizing sterile conditions at each step, is routinely used for facilitating
the germination of wild Helianthus species (Seiler, personal communication). The seeds are first
surface sterilized for 15 to 20 min using a 1% (w/v) solution of sodium hypochlorite, rinsed with
distilled water, and then scarified by cutting a small portion of the seed coat from the wide end of
the seed. The seeds are then treated with GA3 at 100 mg·l–1 in distilled water for 1 h and subsequently
placed on moist filter paper in a petri dish and held in the dark overnight (21°C). The following
day the seed coat is carefully removed and the seedling rinsed with water, placed in a new petri
dish with moist filter paper, and returned to dark storage for 2 days. A fungicide such as benomyl
can be used to reduce the possibility of fungi contamination. After 2 days, the petri dishes are
placed under fluorescent lighting until the seedlings are of sufficient size for transplanting.
Jerusalem artichoke seeds are not used as reproductive propagules for commercial production
of the crop since the plants have relatively high levels of male sterility and incompatibility and the
seed, when present, generally represents crosses between the mother plant and an unknown pollen
donor. Thus, the genetic makeup of the seed is unknown, and with many polyploid species, the
propensity for the offspring to be superior to the parent lines is generally extremely low. For
example, from around 8,000 seedlings in a Jerusalem artichoke breeding program, only 17 were
saved for evaluation from clonal material in the subsequent year (Mesken, 1988). In addition,
Jerusalem artichokes derived from seed typically are less vigorous than the plants emerging from
tubers. Hence, plants from tubers grow much more rapidly and establish a closed canopy more
quickly. Finally, Jerusalem artichoke seeds typically have a low germination rate, decreasing their
potential utility as a commercial means of propagation. Thus, while there have been occasional
reports of successful production of the crop from seed (Lim and Lee, 1990), the potential of seed
at this point in the genetic manipulation of the crop remains remote.
that should work too. 