Abstract
The effect of source reduction on yield and yield components of three maize hybrids at three plant densities was studied under agro-climatic conditions in southern Iran. Field experiments were conducted at the research farm of the College of Agriculture, Shiraz University, Shiraz, Iran, located at Bajgah (52° 35′ N and 39° 4′ E, 1810 masl) during the 2008 and 2009 growing seasons. The treatments included three hybrids, three plant densities and defoliation, arranged in the main, subplots and sub-subplots, respectively. Defoliation treatments, which consisted of removing all the leaves from one side of the maize plants, were imposed when plants were at the silking stage. Silking was taken as the time when 50% of the plants in a row presented visible silks. Partial defoliations included control, and 50% defoliation at 25 and 35 days after silking (defoliation treatments were applied to all plants in each plot). The experiments were conducted in a randomized complete block (RCB) design with three replications. Dry matter accumulation was assessed by sampling ears at 7-day intervals from the mid-silking stage to black layer formation. Defoliation treatments decreased grain yields significantly in both years. The highest grain yield in 2008 (19 t ha−1) was obtained from hybrid Maxima ‘524’ and in 2009 (14 t ha−1) from hybrid 704 at 95,000 plants ha−1 density. Defoliation treatments decreased grain yields due to a reduction in the number of kernels per ear, as well as mean kernel weight. Some other measured parameters including stalk, shank, husk and cob dry weights, and cob and ear lengths were also decreased under defoliation treatments. If 50% of the photosynthetic area after silking was removed, the quantity of retransferred assimilates from stalk to kernel was increased. Finally, partial defoliation, 25 days after silking, reduced all the yield components more than any other treatments.
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Claims 9
Claim · model-written summary
Defoliation significantly decreased maize grain yield in both years.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Defoliation treatments decreased grain yields significantly in both years”
t0“maize hybrids”
Claim · model-written summary
Maxima ‘524’ had the highest grain yield in 2008.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest grain yield in 2008 (19 t ha−1) was obtained from hybrid Maxima ‘524’”
t0“maize hybrids”
Claim · model-written summary
Hybrid 704 at 95,000 plants ha−1 had the highest grain yield in 2009.
- Material
- hybrid 704e0
- Treatment
- 95,000 plants ha−1 densitye0
- Outcome
- grain yielde1
- Direction
- higheste1
- Value
- 14 t ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in 2009 (14 t ha−1) from hybrid 704 at 95,000 plants ha−1 density”
e1“The highest grain yield in 2008”
t0“maize hybrids”
Claim · model-written summary
Defoliation reduced kernels per ear.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Defoliation treatments decreased grain yields due to a reduction in the number of kernels per ear”
t0“maize hybrids”
Claim · model-written summary
Defoliation reduced mean kernel weight.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Defoliation treatments decreased grain yields due to a reduction in the number of kernels per ear, as well as mean kernel weight”
t0“maize hybrids”
Claim · model-written summary
Defoliation decreased stalk, shank and husk dry weights.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stalk, shank, husk and cob dry weights, and cob and ear lengths were also decreased under defoliation treatments”
t0“maize hybrids”
Claim · model-written summary
Defoliation decreased cob dry weight and cob and ear lengths.
- Treatment
- defoliation treatmentse0
- Outcome
- cob dry weights, and cob and ear lengthse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cob dry weights, and cob and ear lengths were also decreased under defoliation treatments”
t0“maize hybrids”
Claim · model-written summary
Removing half the photosynthetic area after silking increased retransferred assimilates from stalk to kernel.
- Treatment
- 50% of the photosynthetic area after silking was removede0
- Outcome
- quantity of retransferred assimilates from stalk to kernele0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“If 50% of the photosynthetic area after silking was removed, the quantity of retransferred assimilates from stalk to kernel was increased”
t0“maize hybrids”
Claim · model-written summary
Partial defoliation 25 days after silking reduced yield components more than other treatments.
- Treatment
- partial defoliation, 25 days after silkinge0
- Outcome
- all the yield componentse0
- Direction
- reducede0
- Comparator
- any other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“partial defoliation, 25 days after silking, reduced all the yield components more than any other treatments”
t0“maize hybrids”
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