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PHOTOPERIOD RESPONSE IN RICE ( ORYZA SATIVA L.)
Author(s) -
CHANDRARATNA M. F.
Publication year - 1954
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1954.tb05249.x
Subject(s) - oryza sativa , photoperiodism , inflorescence , biology , oryza , horticulture , botany , humanities , philosophy , gene , genetics
Although photoperiod eflFects in rice have been extensively studied, the information available is surprisingly meagre. The quantitative nature of the response in this plant has been insufficiently stressed in previous work. Conflicting conclusions have been drawn from comparisons of single photoperiods with the fluid 'control' provided by natural day. The construction of response curves covering an adequately extensive range of photoperiods is an essential preliminary to the analysis of varietal behaviour. The response picture remains incomplete unless the range includes the photoperiod that exercises the maximum effect. Moreover, it is clear that any estimate of the photoperiod sensitivity of a variety must relate to the gradient of its response curve. The concept of photoperiod sensitivity has not hitherto been precisely defined, although the existence of marked differences in varietal sensitivity is generally realized, and the recognition of period-fixed and season-fixed forms is based on these differences. Analogy with results obtained with other species suggests that the various stages leading from inflorescence initiation to maturity in rice may differ in their photoperiod requirements. Published work has been largely confined to the gross effect of day length on heading or blooming, and the study of dissected primordia which is necessary for resolving component effects has been conspicuously neglected. Wagenaar (1952) provides an excellent review of the literature that has accumulated on photoperiodism in rice. The work reported herein includes {a) the construction of response curves, and the calculation from them of parameters that permit the characterization of differences in varietal reaction, and {b) the separation of photoperiod effects on the initiation and the further development of inflorescence primordia.