The Effect of Increased Temperature on Flowering Behaviour of Saffron (Crocus sativus L.)

پژوهشهای زراعی ایران

Article 15, Volume 8, Issue 2 - Serial Number 16, May and June 2010, Pages 324-335   

Document Type: Research Article

DOI: 10.22067/gsc.v8i2.7530

Authors

A Koocheki^* ; A Alizadeh; A Ganjeali

Abstract

Abstract
Flowering in saffron requires a period of incubation at high temperatures for flower differentiation followed by a period of low temperatures for flower emergence. Global warming could adversely affect the flowering of saffron because of its high sensitivity to temperature. Flowering behaviour of saffron in response to rising temperature was studied in an experiment conducted in controlled environment. Corms with identical sizes were collected form green or fully withered field grown plants and sown in plastic pots. Pots were incubated in 25, 27 and 30 °C for 70, 90 and 120 days. By the end of each incubation period, pots incubated in 25, 27 and 30 °C were transferred to 17, 19 and 21 °C, respectively. Days to flowering, development rate and growth characteristics of saffron were measured in alternative temperature regimes of 25/17, 27/19 and 30/21 °C in combination with 3 incubation periods and in 3 replications. The results indicated that increasing incubation temperature up to 27 °C had no significant effects on saffron flowering behaviour however, no flower was appeared from corms incubated in 30°C. Increased duration of incubation period had adverse effects on flower emergence and corms incubated for 120 days were only flowered in 27/19 °C temperature regime. The optimal flowering response and the highest number of vegetative buds was obtained when 90 days incubation period at 27 °C was followed by a period for flower emergence at 17°C. Corms lifted from green or withered plants showed similar response to temperature regimes and incubation periods. However, in average duration of sowing to flowering was 5 days longer in corms lifted from green plants. Comparing the results of this research with daily temperature in the main saffron production areas of Khorasan provinces showed that increasing mean daily temperature by 2 °C during summer and autumn results in a considerable delay in flowering of saffron.

References