Photoperiodic response of five new line selections of soybean (Glycine max (L.) Merill) in the Philippines

Date

2026

Degree

Bachelor of Science in Agriculture

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

M. R. Vega

Co-adviser

F. C. Manuel

Abstract

The photoperiodic response of five new line selections of soybeans developed at UPCA was deter- mined. In the first experiment test plants were subjected to varying photoperiods ranging from 6 to 18 hours. In the succeeding experiments, the minimum number of photoinductive cycles needed to initiate flowering, the age of ripeness-to-flower as well as the daylength requirement of each partial step in the reproductive process were determined using as test material either the most or least photoperiod-sensitive of the line selections tested.

]All the line selections investigated were found to be photoperiod-sensitive; they were all short-day requiring in flowering. However, they varied in degree of sensitivity to photoperiod. The 200-series lines (CES-276, 295) had a critical daylength of about 15.5 hours while the 400-series (CES-407, 434 and 486) lines was about 16-16.5 hours. No flowering occurred under daylengths in excess of these respective lengths. The same pattern of variation was also detected in number of days or plant nodes to first flower intensity of flowering induced.

The age of ripeness-to-flower for all line selections was apparently 5 days; the plants at this stage are roughly in their simple leaf stage. At least 10 photoinductive cycles are needed to initiate flowering.

Pod set was found to require shorter photoperiods while pod development evidently requires longer ones. The probable physiological explanation as well as the implication in the regional dissemination of these line selections of the responses observed is  discussed.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 B62 B35

Notes

Botany

Document Type

Thesis

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