IBIS-Flora

Angiosperm Flora of India

Thermal time approach to predicting seedling emergence dates of red clover, white clover and lucerne in farm fields

Publication Type:Journal Article
Year of Publication:2010
Authors:Sakanoue, S
Journal:Grass and Forage Science
Volume:65
Issue:2
Date Published:2010
ISBN Number:1365-2494
Keywords:base temperature, Medicago, Medicago sativa L., Seed germination, T. repens L., thermal constant, Trifolium, Trifolium pratense, Trifolium pratense L.
Abstract:

A practical method for predicting seedling emergence dates of red and white clovers, and lucerne is proposed. The germination response at seven different constant temperatures ranging from 5 to 35°C was examined. Germination rate, which is a reciprocal of the duration for 50% germination of seeds, was linearly regressed against temperature to calculate the base temperature and thermal constant of seed germination. The calculated values were 3·9°C and 15·8 degree days for red clover, 4·2°C and 13·6 degree days for white clover, and 2·9°C and 17·7 degree days for lucerne. Using the base temperatures, thermal constants, and the daily mean air temperatures at the study site, the seedling emergence dates of the three forage legumes were predicted. At the same time, in an outdoor pot experiment, seeds of these legumes were sown approximately every 3 weeks and seedling emergence dates were determined. The predicted dates of seedling emergence generally fitted the observed dates. Another prediction was attempted using the base temperatures, thermal constants, and normal daily mean air temperatures recorded over more than 30 years in the study site. This prediction showed that the seedlings of the three forage legumes began to emerge at the beginning of April and could continue to emerge until the beginning of November when their non-dormant seeds were present in the site, and that when the seeds were sown from mid-November of one year to late March of the next year, the emergence of seedlings was delayed until the beginning of April.

URL:http://dx.doi.org/10.1111/j.1365-2494.2010.00739.x
Short Title:Grass and Forage Science
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