Effects of vernalization, photoperiod, and temperature on phenological development and spikelet number of Australian wheat

1970 ◽  
Vol 21 (3) ◽  
pp. 383 ◽  
Author(s):  
NJ Halse ◽  
RN Weir
Keyword(s):  
Field Experiments ◽  
Day Length ◽  
Controlled Environment ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Cold Temperatures ◽  
Australian Wheat ◽  
Short Days

Sixteen Australian wheat cultivars grown in controlled environment cabinets demonstrated a range of responses to seed vernalization varying from little or no promotion of floral initiation in Darkan, Kondut, Falcon, and Sunset to about 3 weeks in Festiguay, Claymore, and Mexico 120. Under short days (10 hr photoperiod v. 14 hr) or cold temperatures (12/7�C day/night v. 18/13�) the response to seed vernalization was reduced. None of the cultivars responsive to vernalization achieved floral initiation earlier under cold temperatures than under warm temperatures, even in the absence of seed vernalization. All cultivars achieved floral initiation earlier in long days but the magnitude of the response varied considerably among them. Long days similarly accelerated development from initiation to anthesis. Higher temperatures accelerated development to initiation and anthesis in all cultivars, with only minor differences in magnitude of response. Selected treatments in the cabinets gave rates of development to initiation which closely paralleled results for the same cultivars in field experiments. The number of spikelets per head varied considerably with cultivar, day length, and vernalization treatment. Within the range of conditions of the experiments, temperature did not affect spikelet number other than through vernalization. At either temperature, the spikelet number was closely and positively related to the number of days to floral initiation.

An upper limit for spikelet number per ear in wheat as controlled by photoperiod

1971 ◽  
Vol 22 (4) ◽  
pp. 537 ◽  
Author(s):  
HM Rawson
Keyword(s):  
Day Length ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Upper Limit ◽  
Long Duration ◽  
Concurrent Development ◽  
Double Ridge

In seven diverse wheat cultivars, spikelet number per main ear as influenced by day length was approaching a maximum at 30. Differences in final spikelet number between treatments and cultivars arose from differences in double ridge number at floral initiation (range from 3 to 12), in the rate of production of spikelet primordia (from 0.60 to 1.78 spikelets per day), and in the duration of production. In cultivars with a high final spikelet number, fertility towards the tip of the ear was linked with the establishment of many spikelet primordia before the appearance of glume initials and with the concurrent development of spikelets. Development of the ear of Triticale was also sensitive to day length, with the formation of up to 50 spikelets under an 8 hr photoperiod. The large number of spikelets was achieved by long duration and high rates of production, which were in excess of those for wheat under corresponding photoperiods. Suggestions are made regarding the production of more spikelets per ear in wheat.

Effects of temperature on spikelet number of wheat

1974 ◽  
Vol 25 (5) ◽  
pp. 687 ◽  
Author(s):  
NJ Halse ◽  
RN Weir
Keyword(s):  
Day Length ◽  
Fluorescent Light ◽  
Floral Initiation ◽  
Spikelet Number ◽  
Per Se ◽  
Effects Of Temperature ◽  
Short Days

The number of spikelets on the primary inflorescence of wheat was shown to vary with temperature per se in addition to any vernalization effects. Temperature affected spikelet number principally by influencing the rate and duration of appearance of primordia after floral initiation. However, in the absence of seed vernalization in cultivars responsive to vernalization, temperature also affected the number of spikelets arising from primordia already present on the apex at initiation. Maximum spikelet number resulted from intermediate temperatures which varied in 13.5-hr photoperiods from 10/5°C for Sunset to 22/17° for Mexico 120. There was an interaction with day length: most cultivars reached maximum spikelet number at lower temperatures in short days than in longer days. When the total amount of illumination was increased by providing a longer period of fluorescent light, spikelet number was increased with little interaction with other factors. The rate of appearance of primordia on the primary apex increased at the time of floral initiation.

Day-length influence on reproductive development and tillering in ‘Fergus’ barley

1975 ◽  
Vol 53 (23) ◽  
pp. 2770-2775 ◽  
Author(s):  
D. T. Fairey ◽  
L. A. Hunt ◽  
N. C. Stoskopf
Keyword(s):  
Hordeum Vulgare ◽  
Reproductive Development ◽  
Tiller Number ◽  
Day Length ◽  
Floral Initiation ◽  
Internode Elongation ◽  
Spikelet Number ◽  
Hordeum Vulgare L ◽  
Initial Formation ◽  
Double Ridge

Effects of variation in day length on spikelet and tiller development were studied in a two-rowed barley, Hordeum vulgare L. cultivar ‘Fergus.’ Spikelet number and the length of the spikelet-forming phase increased with progressive reductions in day length from 24 to 12 h. However, increases in spikelet number were offset by abortion of spikelet primordia during spikelet differentiation and elongation of the stem internodes. Floral initiation occurred at all day lengths, but intemode elongation and heading were markedly delayed at 12 h. The cessation of spikelet initial formation and the beginning of internode elongation did not occur simultaneously in any day length. The latter began just before or at double ridge formation.Tiller numbers were highest at 12 h and progressively decreased in longer day lengths. Each plant produced four primary tillers at all day lengths, and differences in tiller number were accounted for by secondary and tertiary tiller production.

Responses of Some Turkish Wheat Cultivars to Vernalization and Photoperiod

1988 ◽  
Vol 24 (2) ◽  
pp. 237-245
Author(s):  
Serpil Terzioğlu
Keyword(s):  
Bread Wheat ◽  
Normal Development ◽  
Photoperiodic Response ◽  
Reliable Information ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Primary Shoot ◽  
Time Of Year ◽  
Short Days

SUMMARYThe vernalization and photoperiodic response of six locally adapted bread wheat cultivars grown under natural daylength conditions during the summer or winter months was examined in glasshouse experiments. The wheat was vernalized by chilling imbibed grains at 2 ± 1°C for 0, 15 or 45 days. Vernalization for 45 days followed by long summer days led to floral initiation in all cultivars within 28 days but vernalization for 0 or 15 days only led to floral initiation in one cultivar. Vernalization followed by long days reduced the time from transplanting to anthesis, resulting in early ear emergence. Vernalization followed by short days accelerated the development of all the cultivars, but normal development could also occur without vernalization at this time of year. Apical differentiation of the primary shoot and its length and development gave the most reliable information on the period of vernalization required.

Effect of phosphorus applied as superphosphate on rate of development and spikelet number per ear of different cultivars of wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Constant Temperature ◽  
Leaf Number ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Main Shoot ◽  
Spikelet Number ◽  
Vegetative Phase ◽  
Rate Of Development ◽  
Elongation Phase

The effects of adding phosphorus (40 kg of phosphorus ha-1) at sowing on rate of development, spikelet number per ear, rate of spikelet initiation, apex length at floral initiation, and leaf number at ear emergence of the main shoot of seven wheat cultivars were studied under a 16 hr photoperiod at a constant temperature of 20°C. Phosphorus additions increased the spikelet number per ear, rate of spikelet initiation, and apex length significantly in all wheats, but had no effect on the duration of the vegetative phase, spikelet phase or elongation phase, or on leaf number. The increase in spikelet number was due to an increase of spikelet initiation. All wheats responded similarly to addition of phosphorus.

Determination of spikelet number in wheat. II.* Effect of varying light level on ear development

1977 ◽  
Vol 28 (4) ◽  
pp. 575 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson ◽  
Y Aitken
Keyword(s):  
Light Level ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Rate Of Development ◽  
Light Levels ◽  
Two Factors ◽  
Lower Light ◽  
Ear Number

The effects of two light levels (0.98 and 4.90 cal cm-2 hr-1) on rate of development and spikelet number per ear were studied in eight wheat cultivars grown under a 16 hr photoperiod at 20°C. The objective was to ascertain how light affects spikelet number. At the lower light level the durations of the vegetative, spikelet and ear elongation phases were greater, but the number of spikelets per ear, number of phytomers present at floral initiation, final leaf number, number of phytomers that were converted into spikelets, apex length at floral initiation and rate of spikelet initiation were smaller than at the higher light level. Responses to varying light level for a11 these parameters were similar for different cultivars, but the sizes of the responses differed. Within a given cultivar, an increase in spikelet number was associated with longer apices at floral initiation and a higher rate of spikelet initiation. It was concluded that these two factors are important determinants of spikelet number. ___________________ *Part I, Aust. J. Agric, Res., 28: 565 (1977).

Determination of spikelet number in wheat. I. Effect of varying photoperiod on ear development

1977 ◽  
Vol 28 (2) ◽  
pp. 265 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Shoot Apices ◽  
Rate Of Development ◽  
Ear Development ◽  
Main Factors ◽  
Photoperiod Control

The effects of constant photoperiods (8, 9, 10, normal and 24 hr) and of transfer to another photoperiod at floral initiation (from 24 hr to 10 and vice versa) on rate of development and spikelet number per ear were studied in eight wheat cultivars grown at 20°C. The objective was to know what factors related to photoperiod control spikelet number. The lengths of the vegetative, spikelet and ear elongation phases, the numbers of spikelets and leaves, the numbers of phytomers and lengths of the shoot apices at floral initiation increased, but the rate of spikelet initiation decreased, as the photoperiod decreased from 24 to 8 hr. Responses to varying photoperiod for all these parameters were similar in the different cultivars but the sizes of the responses differed. Within a given cultivar, an increase in spikelet number was always associated with longer durations of the vegetative and spikelet phases and longer apices at floral initiation. The results of the transfer treatments suggest that spikelet number is not fully determined by the time of floral initiation, but can be altered significantly by manipulating the environment during the spikelet phase. It was concluded that the main factors determining spikelet number are rate and duration of spikelet initiation.

scholarly journals Frost hardening in white cedar container seedlings exposed to intermittent short days and cold temperatures

1991 ◽  
Vol 67 (5) ◽  
pp. 542-544 ◽  
Author(s):  
S. J. Colombo ◽  
E. M. Raitanen
Keyword(s):  
Day Treatment ◽  
Frost Hardiness ◽  
Day Length ◽  
Cold Temperatures ◽  
Thuja Occidentalis ◽  
Frost Hardening ◽  
White Cedar ◽  
Container Seedlings ◽  
Dark Green ◽  
Short Days

Shoot frost hardiness development in white cedar (Thuja occidentalis L.) container seedlings in response to intermittent short days (4 days per week) and warm (not less than 15 °C) or cool (10/5 °C, day/night) temperatures was assessed using the diffusate-electrical conductivity technique. A slight increase in frost hardiness was found within 2 weeks of the start of warm, short days. Frost hardiness increased linearly with time under warm, short days from week 7 to week 14, with seedlings being resistant to damage at −10 °C on week 14. Approximately one-quarter of the seedlings developed brown-green foliage colour after 5 weeks of warm, short day treatment. These seedlings were significantly more frost hardy than the remainder of the seedlings which had dark green foliage. Seedlings exposed to warm, intermittent short days for 13 weeks and then to cool continuous short days for a further 6 weeks became hardy to −20 °C, while seedlings exposed to warm, intermittent short days only for the full 19 week period did not harden to the −20 °C level. Key words: Thuja, day length, photoperiod

Determination of spikelet number in wheat. III.* Effect of varying temperature on ear development

1978 ◽  
Vol 29 (3) ◽  
pp. 459 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Floral Initiation ◽  
Wheat Cultivars ◽  
Variable Response ◽  
Spikelet Number ◽  
Rate Of Development ◽  
Ear Development ◽  
Elongation Phase

The effects on rate of development and spikelet number per ear in eight wheat cultivars grown at various temperatures (16/9, 23/16, and 30/23°C for 8/16 hr) throughout or transferred from one temperature to another at floral initiation were studied under normal (12.5–14.0 hr) and 24 hr photoperiods. Under a 24 hr photoperiod, the durations of the vegetative, spikelet and elongation phases, and spikelet number per ear decreased as the temperature increased from 16/9 to 30/23°C in all cultivars. The rate of spikelet initiation increased as temperature increased from 16/9 to 23/16° in most cultivars, but further increase in temperature caused a variable response. Under a normal photoperiod, increasing the temperature from 16/9 to 23/16°C changed spikelet number little, but further increase in temperature decreased it in most cultivars. The rate of initiation increased, but the durations of the vegetative, spikelet and elongation phases, and the apex length at floral initiation decreased in all cultivars as the temperature increased from 16/9 to 23/16°; with further increase in temperature, the rate of initiation, apex length and duration of the elongation phase decreased in most cultivars, but the durations of the vegetative and spikelet phases either increased or changed little. Variation in the number of spikelets per ear in relation to variation in the factors considered to be its possible determinants is discussed with a view to understanding the control of spikelet number. ___________________ *Part II, Aust. J. Agric. Res., 28: 575 (1977).

The long-short day requirement for flowering in Stylosanthes guianensis

1988 ◽  
Vol 39 (2) ◽  
pp. 199 ◽  
Author(s):  
K Trongkongsin ◽  
LR Humphreys
Keyword(s):  
Early Summer ◽  
Controlled Environment ◽  
Floral Initiation ◽  
Previous Exposure ◽  
Spike Density ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Seed Crops ◽  
Incandescent Lamps ◽  
Short Days

Five 'tardio' selections of Stylosanthes guianensis ssp. guiunensis var. pauciflora and S. guiunensis var. guianensis cv. Cook were grown in a glasshouse where natural daylength was shortencd, or extended by incandescent lamps. They did not flower or flowered weakly in 152 cycles of 10 h short days (SD), but flowered more rapidly and prolifically if exposed to 30, 60 or 90 16 h long days (LD) followed by 30 10 h cycles than under natural daylength conditions at 27' 30' S. Increasing the previous exposure to LD reduced the number of 10 h cycles to floral initiation. Similar behaviour was exhibited by cv. Bandeirante which did not flower in 131 cycles of 11 h, but which flowered when SD induction followed 45 to 65 cycles of 14 h. Spike density was positively related to number of LD, which favoured first flower appearance on the terminal apices of lateral rather than of main shoots. CIAT 1283 and cv. Cook grown in controlled environment cabinets at 30�/23� (day/night) did not flower in 140 cycles of 10 h SD, but flowered if LD were interposed before SD induction. Cook had a greater LD requirement of 50 cycles of 14 or 15.5 h for floral initiation, whilst CIAT 1283 had a lesser LD requirement and flowered after 20 cycles of 14 or 15.5 h or after 50 cycles of 12.5 h. These data indicate a qualitative long-short day flowering response. This has implications which favour the higher latitudes for seed production and the early summer sowing of seed crops when plants would receive maximum LD exposure before SD induction occurs.

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