Durations of the photoperiod-sensitive and -insensitive phases of time to panicle initiation in sorghum

Alagarswamy, G. and Reddy, D.M. and Swaminathan, G. (1998) Durations of the photoperiod-sensitive and -insensitive phases of time to panicle initiation in sorghum. Field Crops Research, 55 (1-2). pp. 1-10.

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The development of sorghum is influenced by genes that control sensitivity to photoperiod, and their interaction with photoperiod and temperature. While temperature influences development throughout the life cycle of plants, photoperiod influences the vegetative stage (from seedling emergence to panicle initiation). In order to simulate plant development, it is essential to know when sorghum plants first become sensitive to photoperiod, and how long that photoperiod sensitivity persists. Ten cultivars with different levels of photoperiod sensitivity were grown in pots under natural climatic conditions both under short day (SD: 8 h photoperiod) and long day (LD: 17 h photoperiod) conditions. Plants were transferred at different times after seedling emergence from SD to LD and vice versa. The time to panicle initiation (PI) for each transfer treatment was determined. In cultivars that remained continuously in SD, the time to PI varied from 16 to 27 days, whereas in continuous LD it varied from 22 to 37 days. The cultivars started reacting to photoperiod 4-9 days after seedling emergence. After sensing photoperiod stimuli, inductive effects among cultivars persisted for 4-14 days in SD, and for 15-33 days in LD depending on their intrinsic photoperiod sensitivity. The sensitivity ended 2-5 days before PI. This interval, between completion of the photoperiod-inductive phase and the actual observation of PI under the microscope, represents the time required for the photoperiod-inductive stimulus to promote sufficient cell division and growth at the shoot apex for the morphological change to become visible as a shiny globular structure. It was concluded that photoperiod sensitivity in these sorghum cultivars ends shortly before or at the PI stage. These results support the assumptions followed in several crop simulation models that sorghum remains photoperiod-sensitive until the completion of the vegetative stage.

Item Type: Article
Author Affiliation: 1CRISAT Asia Center, Patancheru 502 324, Andhra Pradesh, India
Subjects: Crop Improvement > Genetics/Genomics
Crop Improvement > Plant Breeding
Plant Physiology and Biochemistry > Plant Physiology
Plant Physiology and Biochemistry > Biochemistry
Divisions: Sorghum
Depositing User: Syamala
Date Deposited: 27 Oct 2010 04:41
Last Modified: 27 Oct 2010 04:41
Official URL: http://dx.doi.org/10.1016/S0378-4290(97)00039-7
URI: http://eprints.icrisat.ac.in/id/eprint/306

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