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Effects of defoliation at anthesis on grain yield and its components in sunflower (Helianthus annuus L.) in different levels of plant density and sowing date
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Abstract: (3614 Views) |
| Changing crop canopy as to facilitating the interception of more radiation and maximizing photosythosis rate is one of the approaches to increasing crop production. In order to study this hypothesis as well as to determine the effect of the size of source and sink and the role of stem reserved assimilates in grain filling in caps, a field experiment was carried out in split plot arrangement- using complete randomized block design with four replications, in Seed and Plant Improvement Institute Field Experiment Station, Karaj, Iran. In 2006 cropping season. Sowing dates (June 20, Jully 11 and Jully 31) was assigned to main plot and four plant density levels (6, 8, 10 and 10 plants m-2) and three leaf defoliation levels (without defoliation, defoliation of alternate leaves of upper half of plant and defoliation of leaves of lower half of plant) ware randomized in sub-plob and sub-sub plots, respectivety. Results showed that sowing date, plant density and defoliation had significant effect on seed yield, No. of seed m-2, No. of unfilled seed and No. of total seed m-2. The interaction of three factors, howewer was significant on No. of filled seed and unfilled seed m-2 at 5% probability level. Increasing plant density, increased No. of seed m-2, hence the wighest grain yield m-2 was achieved for 12 plant m-2 (2538 kg/ha). Results also revealed that grain yield is more dependent on current photosynthesis and leaves in upper part of plants are more important in determination of grain yield m-2 and its components. |
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| Keywords: Sunflower, Sowing date, Planting density, Defoliation, Grain yield, Yield components, Oil percentage. |
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Full-Text [PDF 2638 kb]
(1169 Downloads)
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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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