A Chrysanthemum plant having flat capitulum form; composite, semi-double decorative flowers; creamy white ray florets; height of approximately 27 cm. in a four inch greenhouse plant and approximately 20.8 cm. as an outdoor garden plant; uniform three week photoperiodic flowering response to short days; being day neutral and insensitive to heat delay and capable of flowering year around under any photoperiodic conditions.

BACKGROUND INFORMATION 
The present invention comprises a new and distinct cultivar of Dendranthema 
grandiflora (Chrysanthemum morifolium Ramat.), identified as MN Sel. 
83-267-3. 
MN Sel. 83-267-3 is a product of a planned breeding program which had the 
objective of creating chrysanthemum inbreds to increase homozygosity at 
loci controlling important phenotypic traits and for eventual use as a 
parent in creating F1 hybrid seed chrysanthemums. The plant originated as 
a seedling from a self-pollination of MN Sel. 79-214-2 (unnamed and 
unpatented), made in 1982 at St. Paul, Minn., during the course of 
breeding efforts in an on-going garden chrysanthemum breeding project. MN 
Sel. 83-267-3 is a second generation inbred. 
MN Sel. 83-267-3 was discovered and selected as one flowering plant within 
the progeny of the stated cross in the fall of 1983, in the St. Paul 
campus field test plots at the University of Minnesota. The first act of 
asexual reproduction of MN Sel. 83-267-3 was accomplished when vegetative 
cuttings were taken in March-April 1984, in a controlled environment in 
St. Paul, Minn., from the initial selection that had been dug from the 
field in October 1983. MN Sel. 83-267-3 has been maintained as part of the 
breeding germplasm for crossing objectives. 
In 1987, MN Sel. 83-267-3 was selected to be included in five environments 
(Chart A) for evaluation as a day neutral (DN) plant. It was established 
to be a three week short day (SD) response group plant. Under increasingly 
stringent long day (LD) photoperiods, it was superior to standard 
greenhouse and garden SD cultivars, as well as garden DN cultivars. Other 
characteristics that made this plant outstanding were the semidouble 
decorative flower type, short plant height, and insensitivity to 
thermophotoperiodic delay in flower bud initiation and development. The 
distinctive characteristics caused us to select the plant for further 
testing for production as a greenhouse pot plant. 
MN Sel. 83-267-3 has not been observed under all possible environmental 
conditions. The phenotype may vary significantly with variations in 
environment such as temperature, light intensity and day length. Under 
normal growing conditions that satisfy the factors for plant growth, the 
normal phenotype occurs. However, we have observed that when grown during 
December through February, with low light levels, the flower color will be 
uniformly purple under any of the following conditions: 1. 62.degree. F. 
nights (N), SD photoperiod (0800-1600 hours); 2. 62.degree. F. N, LD 
photoperiod: natural daylength plus four-hour night interruption (NI) with 
incandescent light (2200-0200 hours); 3. 62.degree. F. N, LD photoperiod: 
natural daylength conditions plus 18 hours 400 watt HID-HPS light 
(0300-2100 hours) and 4. 55.degree. F. N, LD photoperiod: natural 
daylength plus four-hour NI with incandescent light (2200-0200 hours). 
These purple flower changes are not sports due to mutation. Descriptions 
of these changes are included as appropriate. Horticultural examination of 
selected units initiated since 1983 have demonstrated that the combination 
of characteristics as herein described for MN Sel. 83-267-3 are firmly 
fixed and are retained through successive generations of asexual 
reproduction. 
Day Neutrality 
Chrysanthemums are quantitative short day (SD) plants for flower bud 
initiation (FBI) and qualitative (obligate) SD plants for flower bud 
development (FBD) (Schwabe, 1952). If a SD plant is grown under 
photoperiods exceeding the 13.5 hour (average) critical SD photoperiod, it 
will not flower (e.g. continue with FBD after FBI). FBD of SD 
chrysanthemums is reversibly controlled by red and far-red light. 
Continuous or intermittent lighting, using either incandescent (red and 
far-red light) or fluorescent (red light) lights, in the middle of each 
long dark period (night) inhibits FBI and FBD in SD cyrysanthemums (Cathey 
and Borthwick, 1970). 
All SD chrysanthemums eventually initiate terminal flower buds (i.e. 
undergo autonomous FBI) under long day (LD) conditions (Langton, 1977). 
They will not, however, continue with FBD under LD conditions unless they 
are day neutral (DN). True DN plants are rare. In a DN plant, FBD is not 
inhibited by LD photoperiods and will continue (following autonomous FBI) 
for all flower buds (primaries, secondaries, tertiaries, etc.) under any 
photoperiodic conditions, e.g. SD or any LD (in which the duration of 
light is longer than the critical SD photoperiod), and with any 
combination of light quality (red, far-red, red/far-red). 
Cathey, H. M. and H. A. Borthwick, 1970. Photoreactions controlling 
flowering of Chrysanthemum morifolium (Ramat. and Hemsl.) illuminated with 
fluorescent lamps. Plant Physiology 45:235-239. 
Langton, F. A. 1977. The response of early-flowering chrysanthemums to 
daylength. Scientia Horticulturae 7:277-289. 
Schwabe, W. W. 1952. Effects of temperature, daylength, and light intensity 
in the control of flowering in the chrysanthemum. Report of the 13th 
International Horticultural Congress 2:952-960. 
Potential Impact of Day Neutral/Heat Insensitive Cultivars 
Day neutral (DN) and heat delay insensitive cultivars could impact 
greenhouse chrysanthemum production in several ways. Cultivars insensitive 
to heat delay have already proved useful to the commercial grower, 
allowing for scheduling of such cultivars under any high temperatures 
normally incurred in greenhouse production schedules 
(30.degree.-39.degree. C.) When this trait is coupled with day neutrality, 
thermophotoperiodic interactions (heat buildup under black cloth used for 
short day photoperiods) are eliminated, allowing for production in the 
wide range of temperatures and photoperiods inherent with seasonal and 
latitudinal changes. Genotypes such as Mn. Sel. 83-267-3 should be 
adaptable to a wider latitudinal and seasonal production range than 
currently available heat-delay insensitive cultivars which are not DN. 
Since a DN cultivar will flower under any photoperiod, there is no need for 
chrysanthemum growers to manipulate the environment to induce flowering. 
Manual or automated photoperiodic black cloth, used to induce short days 
for flowering, would become unnecessary and/or obsolete. This would 
eliminate the costs of initial investments in the black cloth system, 
maintenance and depreciation, as well as the labor involved in operating 
the system twice daily. In addition, the commercial production protocols 
of 2-3 weeks of long days for vegetative growth, followed by 8+ weeks of 
short days for flower bud initiation and development would be unnecessary. 
A DN cultivar does not need to be moved into long and then short day 
photoperiods for flowering. Rather, such cultivars could be flowered under 
naturally long daylengths (spring to fall) and supplemental long day 
lighting could be added during winter months (low light conditions and 
short day photoperiods) or they could be flowered using current production 
schedules until growers phase out investments in existing black cloth 
systems.