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Testing for Early Photoperiod Insensitivity in Soybean
Author(s) -
Wang Zhongchun,
Reddy Vangimalla R.,
Acock Mary C.
Publication year - 1998
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1998.00021962009000030012x
Subject(s) - photoperiodism , seedling , biology , cultivar , juvenile , agronomy , horticulture , botany , ecology
To accurately model the flowering process in soybean, it is essential to identify photoperiod‐sensitive and photoperiod‐insensitive phases of development. Despite extensive studies, there remains some disagreement about when soybean plants first become sensitive to photoperiod. The length of the juvenile phase from emergence has been found to differ for the same cultivar. This experiment tested the hypothesis that the early phase in soybean development is truly photoperiod‐independent. Soybean plants [ Glycine max (L.) Merr. cv. Hutcheson; Maturity Group V] grown in controlled environments at a constant air temperature of 26°C were transferred from a noninductive 22‐h photoperiod to an inductive 8‐, 10‐, 12‐, or 14‐h photoperiod at 2‐ to 5‐d intervals after seedling emergence (defined as the day when the cotyledons appeared above the soil surface). The duration of the so‐called juvenile phase was shown to be photoperiod‐dependent, the photoperiod effect being nonlinear. Soybean plants became sensitive to an 8‐, 10‐, 12‐, and 14‐h photoperiod at ‐1, 0, 1, and 9 d after seedling emergence, respectively. Based on these and other results, we conclude that there is no juvenile phase in Hutcheson soybean, and that photoperiod sensitivity begins when seedlings are exposed to light, but the rate of progress towards flowering depends on the photoperiod experienced.