ٍٍEffects of sowing date and heat stress during flowering on yield and yield components in canola (Brassica napus L.) cultivars
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Abstract: (4338 Views) |
Flowering duration of canola is exposed to high temperature and heat stress in Khouzestan, Iran. The main objective was to examine the effects of sowing date and heat stress during flowering on yield and yield components of three spring canola cultivars. The experiment was conducted at Ramin Agricultural Research and Educational Center during 2003-4 and 2004-5 cropping seasens. Hyola-308, PF-7045/91 and Heros cultivars were planted as subplot in a split-plot experiment with three sowing dates 21 November, 10 and 30 December as main-plot with four replications. The results showed that biological and seed yields as well as yield components (except the number of seeds per silique) decreased significantly with delay in sowing date. Seed yield and yield components were significantly different among cultivars, however biological yield was not. Hyola-308 and Heros produced the highest (327.74 g.m-2) and the lowest (203.26 g.m-2) seed yields, respectively. The threshold temperature (Tt) during flowering was not significantly different among cultivars and their mean value was
28.3 °C. During flowering, the maximum daily temperatures greater than 28.3 °C were accumulated as heat stress units. The number of flowers and siliques per main raceme and the ratio of the number of developed siliques to the number of established flowers reduced as heat stress units increased, but the number of seeds per silique increased in Hyola-308 and decreased in two other cultivars. Based on the results of this study, middle and late maturing cultivars of canola are not suitable for Khouzestan climatic conditions, therefore, early maturing cultivars are recommended. |
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Keywords: Canola, sowing date, heat stress, threshold temperature, yield, yield components |
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Full-Text [PDF 365 kb]
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Type of Study: Scientific & Research |
Subject:
Special Received: 2015/02/28 | Accepted: 2015/02/28 | Published: 2015/02/28
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