Flowering in Townsville lucerne (Stylosanthes humilis). 2. The effect of latitude and time of sowing on the flowering time of single plants

1967 ◽  
Vol 7 (29) ◽  
pp. 495 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Flowering Time ◽  
Low Temperatures ◽  
Full Range ◽  
Moisture Stress ◽  
Early Maturity ◽  
Controlled Conditions ◽  
Stylosanthes Humilis ◽  
Sowing Dates ◽  
Maturity Type ◽  
Maturity Groups

The flowering times of seventeen selections of Townsville lucerne (Stylosanthes humilis HBK) have been studied at three localities and six sowing dates. The selections were grown as spaced plants and the full range of maturity types (Cameron 1965) was represented. The repeatability of flowering time between years was high, with no differences in the order of flowering of the different maturity groups. There was a range of 56 days in flowering time between the early and late groups for a December sowing, but this was reduced to 8 days for a March sowing. The maturity type groups were not clearly differentiated at the March sowing. Most selections flowered progressively later the more southerly the location and this effect was greatest for the early maturity types. Most of the flowering time responses were closely related to changes in daylength and very similar to results previously obtained in controlled conditions (Cameron 1967a). However, low temperatures, shading and moisture stress also delayed the flowering of some selections.

The inheritance of flowering time in Townsville stylo (Stylosanthes humilis)

1976 ◽  
Vol 27 (6) ◽  
pp. 825 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Flowering Time ◽  
Dominant Gene ◽  
Diallel Cross ◽  
Early Flowering ◽  
Multiple Alleles ◽  
Locus Model ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Maturity Groups ◽  
Early Flowering Phenotype

The inheritance of flowering time was studied in F1, F2 and F3 populations derived from a diallel cross among nine naturalized Australian lines of Townsville stylo (Stylosnnthes humilis) and in F1 and F2 populations from a small number of crosses between naturalized Australian lines and introductions from Mexico and Brazil. Strong dominance for lateness of flowering was observed in both the (Australian x Australian) and the (Australian x Mexican/Brazilian introductions) crosses, and some F2 and F3 progenies included small numbers of extremely early plants, flowering up to 55 days earlier than the earliest parent. The flowering time distributions of the (Australian x Australian) crosses could be explained by a three-locus model with multiple alleles at two loci. Proposed genotypes for the four maturity groups are as follows: late, LLM2M2EE; late-midseason, LLmmEE; mid-season, l2l2M2M2EE; early, l1l1M1M1EE; very early, LLM2M2ee. Only one major dominant gene for lateness of flowering could be detected from the distribution of the two (Australian x introduced line) F2 populations, but the segregation of extremely early types and the low recovery of the early-flowering phenotype suggested that other gene loci were segregating.

Effect of time of sowing on flowering and growth of Townsville stylo (Stylosanthes humilis)

1974 ◽  
Vol 14 (67) ◽  
pp. 182 ◽  
Author(s):  
Mannetje L t ◽  
KHLvan Bennekom
Keyword(s):  
Low Temperatures ◽  
Dry Matter ◽  
Late Summer ◽  
Growing Season ◽  
Sowing Date ◽  
Stylosanthes Humilis ◽  
Maturity Type ◽  
Townsville Stylo ◽  
Late Start ◽  
Spring Sowing

A midseason maturity type of Townsville stylo sown at monthly intervals throughout a year in a glasshouse in Brisbane (27�30' south) started flowering from 42 to 76 days after sowing between February and September, with dry matter yields at flowering ranging from 0.05 to 5.82 g/per plant. Sowings between October and January resulted in flowering after 98 to 157 days, with yields ranging from 26.41 to 54.75 g/per plant. Flowering was mainly determined by daylength, although low temperatures during winter delayed inflorescence elongation. Growth after onset of flowering was measured in plants sown in winter, spring and late summer. Plant weights increased after flowering in all sowings. In the spring sowing this consisted entirely of stem and inflorescence, but in the other sowings leaf was formed after onset of flowering as well. Winter and spring sowings gave the highest, late summer sowing the lowest final yields. The main agronomic implication is that sowing early in the growing season is necessary for obtaining a good first year's yield, but that seed production is little affected by sowing date, ensuring good regeneration even in years with a late start of the growing season.

Assessment of sowing dates and plant densities using CSM-CROPGRO-Soybean for soybean maturity groups in low latitude

2021 ◽  
pp. 1-14
Author(s):  
L. S. Sampaio ◽  
R. Battisti ◽  
M. A. Lana ◽  
K. J. Boote
Keyword(s):  
Management Practices ◽  
Field Experiments ◽  
Plant Density ◽  
Crop Model ◽  
Management Scenarios ◽  
Low Latitude ◽  
Area Index ◽  
Sowing Dates ◽  
Plant Densities ◽  
Maturity Groups

Abstract Crop models can be used to explain yield variations associated with management practices, environment and genotype. This study aimed to assess the effect of plant densities using CSM-CROPGRO-Soybean for low latitudes. The crop model was calibrated and evaluated using data from field experiments, including plant densities (10, 20, 30 and 40 plants per m2), maturity groups (MG 7.7 and 8.8) and sowing dates (calibration: 06 Jan., 19 Jan., 16 Feb. 2018; and evaluation: 19 Jan. 2019). The model simulated phenology with a bias lower than 2 days for calibration and 7 days for evaluation. Relative root mean square error for the maximum leaf area index varied from 12.2 to 31.3%; while that for grain yield varied between 3 and 32%. The calibrated model was used to simulate different management scenarios across six sites located in the low latitude, considering 33 growing seasons. Simulations showed a higher yield for 40 pl per m2, as expected, but with greater yield gain increments occurring at low plant density going from 10 to 20 pl per m2. In Santarém, Brazil, MG 8.8 sown on 21 Feb. had a median yield of 2658, 3197, 3442 and 3583 kg/ha, respectively, for 10, 20, 30 and 40 pl per m2, resulting in a relative increase of 20, 8 and 4% for each additional 10 pl per m2. Overall, the crop model had adequate performance, indicating a minimum recommended plant density of 20 pl per m2, while sowing dates and maturity groups showed different yield level and pattern across sites in function of the local climate.

scholarly journals A Chlorophyll Fluorescence Screening Test to Evaluate Chilling Tolerance in Tomato

HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 334-339 ◽  
Author(s):  
Mark A. Walker ◽  
Dale M. Smith ◽  
K. Peter Pauls ◽  
Bryan D. McKersie
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Lycopersicon Esculentum ◽  
Temperature Stress ◽  
Low Temperatures ◽  
Screening Test ◽  
Full Range ◽  
Chilling Tolerance ◽  
Solanum Lycopersicoides ◽  
Commercial Cultivars

The chilling tolerance of commercial Lycopersicon esculentum cultivars (H2653, H722), Solanum lycopersicoides, an F1 hybrid of S. lycopersicoides × Sub-Arctic Maxi, and 25 BC2F2 lines of L. hirsutum × H722 (backcrossed twice to H722) was evaluated using a chlorophyll fluorescence assay. The ratio of the initial to the peak fluorescence (Fo: Fp) measured from fully expanded leaves was chosen as an indicator of plant health. Chilling induced an increase in Fo: Fp that was correlated with the sensitivity of the plant to low-temperature stress. Values of Fo: Fp remained low for cold-treated S. lycopersicoides and the F1 hybrid, which showed few symptoms of chilling-related damage, whereas the commercial cultivars, which were essentially intolerant to low temperatures, had large increases in Fo: Fp. A full range of Fo: Fp values was measured in the 25 BC2F2 lines, indicating that some chilling tolerance from the L. hirsutum parent was expressed by plants in these populations.

Variation in maturity, stolon development and frost resistance of Glycine javanica

1966 ◽  
Vol 6 (23) ◽  
pp. 380 ◽  
Author(s):  
LA Edye ◽  
HJ Kiers
Keyword(s):  
Flowering Time ◽  
Frost Resistance ◽  
Seed Set ◽  
Flowering Period ◽  
Early Variety ◽  
South Eastern ◽  
Discontinuous Variation ◽  
Late Maturity ◽  
Maturity Type ◽  
Stolon Development

Introductions of G. javanica showed wide variation in flowering time, seed set, seed yield, stolon development, and frost resistance at Lawes in south-eastern Queensland. The discontinuous variation in flowering time of 50 introductions over 103 days at Lawes has enabled very early, early, midseason, and late maturity types to be defined. These maturity classes hold equally well when applied at 'Lansdown' in north Queensland. With the exception of C.P.I. 25336, only very early and early introductions set seed in large areas of south-eastern Queensland where frosts are experienced in June and July. C.P.I. 25336, an early variety with an extended flowering period, did not set seed before the first heavy frost on June 24, 1961. The association of maturity type, stolon development, and frost resistance with the country of origin of the introductions is mentioned and the significance of these characters in adapting G. javanica to Australian conditions is discussed.

Seasonal distribution of dry-matter production in grass varieties from different latitudes in northern Europe

1985 ◽  
Vol 105 (1) ◽  
pp. 187-188 ◽  
Author(s):  
R. K. M. Hay
Keyword(s):  
Low Temperatures ◽  
Dry Matter ◽  
Field Experiments ◽  
Seasonal Distribution ◽  
Dry Matter Production ◽  
Northern Europe ◽  
British Isles ◽  
Controlled Conditions ◽  
Matter Production

Work in controlled conditions (Cooper, 1964; østgård & Eagles, 1971) has indicated that, under short photoperiods and low temperatures, Scandinavian grass varieties tend to grow more slowly than those from lower latitudes, and are, therefore, more resistant to cold and freezing stresses. This has been confirmed in field experiments (Håbjørg, 1979). These grasses would therefore be expected to cease growth earlier in the autumn when grown in the British Isles. However, this mechanism does not appear to operate under lengthening days; indeed, there is evidence to suggest that their growth is particularly stimulated by the combination of cool temperatures and long days (Cooper, 1964; Hay & Heide, 1983, 1984). This raises the possibility that varieties from Norway and Sweden could produce more dry matter than grasses of more southern provenance in the spring in upland areas, when low temperatures are associated with rapidly lengthening photoperiod (12·5–15 h) and moderate to high levels of irradiance (> 200 W/m2) (Hay, 1985).

Flowering time and the natural distribution and dry matter production of Townsville lucerne (Stylosanthes humilis) populations

1967 ◽  
Vol 7 (29) ◽  
pp. 501 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Flowering Time ◽  
Dry Matter ◽  
Growth Habit ◽  
Correlation Coefficients ◽  
Annual Rainfall ◽  
Late Flowering ◽  
Matter Production ◽  
Northern Areas ◽  
Stylosanthes Humilis ◽  
Significant Yield

The flowering times of 58 collections of Townsville lucerne from typical sites in northern Australia have been recorded in three spaced plant experiments near Townsville. Thirty-six collections were grown in 1963-64, 15 in 1964-65, and 17 in 1965-66. All the late flowering collections came from sites receiving at least 45 inches annual rainfall. The five collections from south of Rockhampton were all of the early or midseason type and all collections from the far northern areas were late flowering. Partial regression analysis was used to relate the flowering time of a collection to the rainfall (for the five months interval from January to May) and latitude of the collection site. In the first two experiments rainfall, latitude and (latitude)2 all contributed significantly to the regressions, but in the third experiment only rainfall was significant. Correlation coefficients for 1963-64, 1964-65, and 1965-66 were +0.83, +0.97, and +0.93 respectively. A selection was derived from a collection by bulking seed from single spaced plants selected for uniform flowering time and growth habit. The dry matter yields of some collections and selections were compared in two sward experiments near Townsville in 1964-65 and 1965-66. In 1964-65 there were significant yield differences between collections (experiment A, P<0.01) and between selections (experiment B, P<0.001). There were differences in the rates of vegetative growth and differences in the length of growing season, with late flowering types being able to make better growth late in the season when early types were flowering and seeding. Types with erect growth habit had the highest yields and seemed to compete better with sown grasses than the prostrate types. There were no significant yield differences in 1965-66, a very dry year, and the late flowering types failed to set seed.

The relationship of several plant characters with grain yield in sorghum and their use in estimating grain loss through pest activity

1976 ◽  
Vol 16 (78) ◽  
pp. 129
Author(s):  
PN Vance
Keyword(s):  
Grain Yield ◽  
Moisture Stress ◽  
Close Correlation ◽  
Regression Equations ◽  
Grain Number ◽  
Potential Yield ◽  
Sowing Dates ◽  
Single Grain ◽  
Relationship Of ◽  
The Relationship

The relationship between grain yield and five plant characters in grain sorghum hybrid Pioneer 846 was studied. Grain yield was closely correlated with head weight, weight of a standard length of peduncle (WSP), peduncle perimeter (PP), head length and breadth. The close correlation of grain yield on WSP was shown to exist at a number of sites and for a number of varieties. However, regression equations differed for different sites, sowing dates and varieties. Of the two components of grain yield per head, single grain weight and grain number; only grain number was closely correlated with WSP. In one instance where moisture stress affected grain development, grain number but not yield was closely correlated with WSP. WSP was shown not to be affected by damage to the head and could therefore be used to estimate potential yield in agronomic trials where yield loss due to pest activity has occurred.

Assessment of Drought Tolerance Indices in Bread Wheat Genotypes Under Different Sowing Dates

2012 ◽  
Vol 45 (3) ◽  
pp. 25-39 ◽  
Author(s):  
S. Mohammadi ◽  
M. Janmohammadi ◽  
A. Javanmard ◽  
N. Sabaghnia ◽  
M. Rezaie ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Grain Yield ◽  
High Performance ◽  
Wheat Yield ◽  
Moisture Stress ◽  
Drought Indices ◽  
Terminal Drought ◽  
Sowing Dates ◽  
Moisture Conditions

Abstract The capability of a genotype to achieve acceptable yield over a broad range of sub-optimum and suitable conditions is extremely imperative. Late planting and end-season drought stress are two main factors limiting wheat yield in northwest of Iran. In a 2-year field experiment at Miandoab, Iran, the ability of several selection indices to identify drought resistant genotypes under different sowing dates and moisture conditions were evaluated. Six genotypes of differing response to water scarcity were planted at 20-d intervals on three dates from 11 October to 20 November. Drought resistance indices were utilized on the basis of grain yield under end-season drought (Ys) and normal (YN) conditions. Evaluation of MP, HARM, GM, STI, TOL, SSI, RDI, YSI and Yr indicated that late sowing (20 Nov) significantly decreased drought tolerance in all investigated genotypes. However, yield comparisons under normal and terminal drought stress conditions revealed that promising lines (C-81-4, C-81- 10, C-81-14 and C-82-12) had better performance than local checks (Zarrin and Alvand). Furthermore under both moisture conditions C-81-10 genotype had the greatest grain yield. Based on drought indices like as MP, GMP, STI and HARM C-81-10 genotype introduced as the most tolerant genotype to end-season drought stress. Grain yield showed a positive and significant correlation with HARM, GMP, MP, STI and YI indices were more efficient for recognizing high performance genotypes under different sowing dates and diverse moisture stress.

A study of the reactions of 2-Aryl-3,3-dimethylbicyclo[2,2,1]heptan-2-ols with acid

1978 ◽  
Vol 31 (8) ◽  
pp. 1747 ◽  
Author(s):  
JM Coxon ◽  
PM Projer ◽  
PJ Steel ◽  
ID Rae ◽  
AJ Jones
Keyword(s):  
Perchloric Acid ◽  
Low Temperatures ◽  
Chemical Shifts ◽  
Strong Acid ◽  
Fluorosulfonic Acid ◽  
Controlled Conditions

The 13C and 1H N.M.R. spectra of a series of 2-aryl-3,3- dimethylbicyclo[2,2,1]hept-2-yl cations generated in strong acid at low temperatures are reported. The chemical shifts of carbons proximate to the cation centres are discussed with reference to related cations. At higher temperatures, 2-aryl-3,3-dimethylbicyclo[2,2,1]hept-2-yl cations in fluorosulfonic acid give substituted 7,8-dimethyltetracyclo- [7,4,0,02,7,04,8]trideca-1(9),10,12-trienesulfonyl fluorides. Substituted 7,8-dimethyltetracyclo[7,4,0,-02,7,04,8]trideca-1(9),10,12-trienes and 7,8-dimethyltetracyclo[7,4,0,02,7,04,8]trideca-1(9),10,12-triene were prepared from 2-aryl-3,3-dimethylbicyclo[2,2,1]heptan-2-ols by reaction with perchloric acid under carefully controlled conditions.

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