Tropical Environment of Puerto Rico Useful for Studying Day‐Length Sensitivity in Pearl Millet 1

Crop Science ◽  
1966 ◽  
Vol 6 (2) ◽  
pp. 212-213 ◽  
Author(s):  
D. K. Barnes ◽  
G. W. Burton
Keyword(s):  
Puerto Rico ◽  
Pearl Millet ◽  
Tropical Environment ◽  
Day Length

scholarly journals Recessive, Day Length‐Insensitive Earliness to Synchronize Flowering of Pearl Millet Hybrid Parents

Crop Science ◽  
1999 ◽  
Vol 39 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
F. R. Bidinger ◽  
C. T. Hash ◽  
R. Jayachandran ◽  
M. N. V. Ratnaji Rao
Keyword(s):  
Pearl Millet ◽  
Day Length

scholarly journals Flower Initiation and Tassel Emergence in Sugarcane

1969 ◽  
Vol 55 (1) ◽  
pp. 101-113
Author(s):  
Teh-ling Chu ◽  
J. L. Serapión
Keyword(s):  
Puerto Rico ◽  
Moisture Stress ◽  
Day Length ◽  
Flower Initiation ◽  
Floral Initiation ◽  
Significant Delay ◽  
Sugarcane Varieties ◽  
Predominant Factor ◽  
One Year ◽  
Time Required

Stem apices of 78 sugarcane varieties were examined microscopically to determine the precise date of flower initiation during the 1967 and 1969 flowering periods at Gurabo Substation, P.R. A stage method for measuring floral initiation was developed and adopted. It was found that flower initiation or the formation of flower primordial is not simultaneous among all varieties of sugarcane. Initiation time was found to vary from September 1 to September 30. The model day-length for floral initiation in Puerto Rico (latitude 18° N.) appears to be 12 hours, 7 to 17 minutes. Both time of initiation and speed of inflorescence growth and development was found to be related to the time of flowering. The time required for the development and elongation of inflorescences was from 7 to 10 weeks in 90 percent of the varieties. The time of initiation in respective varieties is fairly constant from one year to the next. This indicates that flower initiation in sugarcane is determined primarily by photoperiod. However, as indicated in these studies, both low temperature and moisture stress were regarded as important factors in delaying the time of flower initiation. Moisture stress during 1967 appeared to be the predominant factor causing significant delay in the time of tassel emergence among the majority of varieties studied.

scholarly journals Planting dates and morphology and growth of four sweet potato clones in Puerto Rico

1969 ◽  
Vol 72 (3) ◽  
pp. 437-444
Author(s):  
Franklin W. Martin
Keyword(s):  
Puerto Rico ◽  
Sweet Potato ◽  
Cultural Factors ◽  
Growth Characteristics ◽  
Day Length ◽  
Linear Quadratic ◽  
Sweet Potatoes ◽  
Planting Dates ◽  
External Variables ◽  
Monthly Distribution

Four clones of sweet potato were planted monthly in 1984, and 11 morphological and growth characteristics were measured. Clones differed with respect to all characteristics, and significant differences were found among months in all but one characteristic. The 11 characteristics could be classified as modal, bimodal, irregular or complex with respect to monthly distribution. Several of the characteristics regressed on months by linear, quadratic or cubic regression. Others were not clearly related and differences are believed to be caused by cultural factors that may have varied. Four external variables affecting sweet potatoes, (day length, rainfall, temperature and solar radiation) could have accounted for many of the observed differences among months.

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude VI. The effect of increased light and injections of vitamin A on semen production and sperm characteristics in tropical rams

1961 ◽  
Vol 56 (2) ◽  
pp. 173-177 ◽  
Author(s):  
R. B. Symington
Keyword(s):  
Vitamin A ◽  
Reproductive Function ◽  
Tropical Environment ◽  
Day Length ◽  
Main Experiment ◽  
Sperm Characteristics ◽  
Electric Light

German Merino, Persian Blackhead and indigenous Native rams were exposed to gradually increasing day-length simulated by use of electric light in the night pen. Between February and June experimental day-length increased from 14 hr. 35 min. to 17 hr. whereas natural day-length fell from 13 hr. 50 min. to 12 hr. An additional trial was superimposed on the main experiment to determine the effect of vitamin A injections on reproductive function and on ability to respond to photoperiodic stimuli.

The Planetary Test

2019 ◽  
Vol 10 (1) ◽  
pp. 13-22
Author(s):  
Orit Halpern
Keyword(s):  
Puerto Rico ◽  
Second World War ◽  
Tropical Environment ◽  
World War ◽  
Climate Control ◽  
History Of ◽  
The Government ◽  
Richard Neutra ◽  
Second World

In 1943, in the midst of the Second World War, the famous architect Richard Neutra was commissioned by the government of Puerto Rico to build hospitals and schools. In response, he produced a number of prototypes and processes investigating different ways to ventilate and climate control buildings in the sub-tropical environment of the island through technology. Neutra famously labeled his work in Puerto Rico a Planetary Test. This article examines this history of making climate a medium for design and the implications of these practices for our present

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