Ratoon Cropping of Sorghum: II. Effect of Daylength and Temperature on Tillering and Plant Development1
- Rodolfo G. Escalada and
- Donald L. Plucknett2
Tillerlng capacity and behavior determine the success or failure of ratoon cropping in grasses. This work was initiated to gain more understanding on the seasonal effects on tillering and ratoon cropping of sorghum [Sorghum bicolor (L.) Moench] in the high rainfall tropics by studying the effects of various daylengths and temperature regimes on plant growth and development and yields of ratoon crops.
Sorghum plants were grown under two daylengths and four temperature regimes in controlled-environment chambers. Temperatures and daylengths used simulated tropical winter and summer conditions similar to rainfed sugarcane (Saccharum officinarum L.) plantations of Hawaii where ratoon sorghum has been grown. It is contemplated that sorghum could be used as an alternate crop for sugarcane plantations phasing out of production and that ratooning the crop could be utilized as a management practice, thus reducing the high cost of production.
An interaction between photoperiod and temperature was observed. With low temperature (23.9 C-day/15.5 C-night) and short day (10 hours), fewer tillers/plant were produced resulting in the development of fewer reproductive tillers. At the same low night and day temperatures, but with photoperiod increased from 10 to 14 hours, more tillers/plant, more reproductive tillers/plant, greater leaf area, more leaves, more numerous but shorter internodes, and longer panicles were produced. The check plants grown outside produced more reproductive tillers/plant than the various treatments. Increasing both the temperature (32.2 C-day/23.9 C-night) and daylength (14 hours) resulted in further increase in tiller number/plant, leaf area, and internode number. Higher temperature and shorter daylength tended to bring about early maturity.
Low light intensity, short photoperiod, and low temperature, resulted in rosette form of foliage with very short internodes and reduced number of leaves. This condition led to low grain and stover yields.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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