Phylogenetic Differentiation of the Cultivated Rice Plant (III). The Responses to day-length and Temperature and the Number of Days of Growth Period
Other Title
稻系統發生的分化 (III).日長溫度與生育日期之反應
Journal
農業研究
Journal Volume
3
Journal Issue
4
Start Page
79
End Page
94
Date Issued
1952-12-08
Date
1952-12-08
Author(s)
H. Oka
Y. C. Lu
K. H. Tsai
岡彥一
盧英權
蔡國海
Abstract
1. Rice varieties of various districts of Eastern Asia, 163 in total number and same to the materials of the preceding works, were seeded repeatedly throughout a year at the intervals of 30 to 50 days, and the relation between the dates of heading and the days of growth period (from seeding to heading) was investigated on each variety. The same experiment was repeated three times. in 1945, 1946-'47 and 1948-'49.
2. For measuring the sensibility to day-length, the ratio of the shortening of growth period to an unit shortening of day-length at the time of flower bud formation (assumed as 30 days before the heading) was calculated on each variety. This ratio varied in a same variety with the day-length; the day-length at which the ratio was largest was regarded as ”critical day-length” and the angle the tangent of which was corresponding to the largest ratio was used as a measure of the sensibility to day-length (named as T. D. M.).
3. As in day-length sensible varietes the days of growth period differed strikingly with the day-length, the response to temperature was measured only on day-length insensible varieties by the following method: to find on each variety the days of growth periods in different dates of heading (Y), average temperatures of respective growth periods (X), and average temperatures at the time of flower bud formation (25-15 days before the heading) (Z), and to calculate the percentage of partial regression coefficients byx.z and byz.x to the average of the days of growth period. byx.z (%) and byz.x (%) will stand for the rates of accerelation of general growth and flower bud formation for the rise of 1℃ respectively. In addition to this, the rate of hastening of flower bud formation by the rise of temperature in spring was measured by another method, and was found to agree well with byz.x.
4. Varietal variation of T. D. M. (coefficient of day-length sensibility) was discontinuous and the varieties were divided into two groups sensible and insensible to clay-length. While northern temperate regions and districts under the equator showed no sensible varieties, from the regions between Japan Proper and Philippine both sensible and insensible varieties were found. Among day-length sensible varieties, the lower the latitude was, the higher was the sensibility to day-length as a general tendency, and the shorter was the critical day-length. These phenon ena were considered to be the adaptation of varieties to the environmental conditions which would be dependent upon the latitude.
5. Among day-length insensible varieties, varieties of Continental group were generally larger in byx.z (the rate of accerelation of general growth for the rise of 1℃) and smaller in byz.x (the rate of hastening of flower bud formation) than Insular varieties. A minus correlation was found between byx.z and by.x. Further, they were found to correlate with Beiehradik's temperature constant in the germination of seed.
6. Day-length sensible varieties were thought to have no definite number of days of growth period practically. In insensible varieties, on the other hand, the days of growth period seemd to be constant when the temperature was uniform in summer. The number of days- of theoretical growth period at 25℃ was calculated on each variety from the multiple regression equation of byx.z and byz.x. The lower the latitude was, the longer was the days of growth period as a general rule among day-length insensible varieties.
Publisher
農業試驗所
Type
journal article
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