Effect of heat stress and planting date on yield, grain quality and fertilizer uptake of rice cultivars (Oryza sativa L.)
In the first experiment, high temperature tolerance, in terms of transplanting dates (1st May, 21st May and 10th June) was tested on six Iranian rice cultivars. The response of rice cultivars and transplanting dates for the morphological, and yield components showed the crop sown on 1st and 21st...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2016
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/92662/1/FP%202016%2058%20-%20IR.pdf |
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| Summary: | In the first experiment, high temperature tolerance, in terms of transplanting
dates (1st May, 21st May and 10th June) was tested on six Iranian rice cultivars.
The response of rice cultivars and transplanting dates for the morphological, and
yield components showed the crop sown on 1st and 21st May had better growth
and yield components which resulted higher grain yield (6625 kg ha") of Neda
cultivar.
The second experiment was glass house conducted to evaluate the effects of
high temperature (38±2°C) stress and normal temperature (32±2°C) on seven
rice cultivars. The results showed the greater weight of 1000 grains (26.97 g)
observed in Neda grown in normal condition. The maximum grain yield (51.3 g
pot") was noted in MR219 planted in normal condition.
In third experiment, the effect of normal and heat stress temperatures were
tested on four rice cultivars (Fajr, Hashemi and Hovaze as exotic and MR219 as
indigenous). The main effects of heat stress and growth stage were significant
in all parameters except on effective tillers. The lowest grain yield per pot was
observed in Hashemi (6.8 g pot") at flowering stage during heat stress condition
and the highest was found in MR219 (42- 45d g pot") during normal condition.
In conclusion, the major reason for yield reduction of all cultivars was
enhancement of sterile and aborted spikelets numbers when plants exposed to
heat stress during booting and flowering phases.
The last experiment was conducted on the rice cultivars from previous
experiment to evaluate the effect of normal temperature and heat stress using
Potassium fertilizer, nitrogen, and Meister-20 (polymer coated urea). The grain
yield was significantly higher (25.9 g pot") in the plants grown in normal condition
and fertilized with Meister-20 at 160 kg N ha". In the heat stress condition, the
grain yield ranged between 15.3 to 17.9 g pot:' in the N fertilized plants which is
also considered satisfactory as compared to unfertilized plants in the heat stress
condition. |
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