DIFFERENTIAL TOLERANCE OF TOO RICE (Oryza sativa L.) CULTIVARS TO DIMETHAMETRYNE
DIFFERENTIAL TOLERANCE OF TOO RICE (Oryza sativa L.) CULTIVARS TO DIMETHAMETRYNE
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Date
1998-11
Authors
ADEKPE, DAVID IDOKO
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Abstract
Both the screen house and field trials were conducted at
Samaru Zaria (11°11'N 7° 35'E) in the Northern Guinea savanna
of Nigeria, to study the tolerance of two selected rice (Oryza
sativa L.) cultivars (ITA 257 and Ex-China) to various rates
of dimethametryne (herbicide). Dimethametryne (herbicide) was
evaluated at 0.25, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0kg
ai/ha.
The result obtained indcated that dimethametryne at low
to near medium rates (0.25 - 1.5kg ai/ha) were well tolerated
while medium to high rates (2.0 - 4.0kg ai/ha) were observed
to be phytotoxic to rice cultivars in both trials.
Dimethametryne at 3.0 - 4.0kg ai/ha resulted in total crop
loss before 4WAS in the screen house trial.
Rice cultivars responded differentially to the various
rates of dimethametryne particularly at medium to high rates
(2.0 - 4.0kg ai/ha) in the field. ITA 257 was found to be
more tolerant to the herbicide rates than Ex-China in both
trials resulting in its (ITA 257) least injury, better growth
vigour, higher LA/plant, shoot dry weight and paddy yield.
Shoot dry weight at 12WAS in the screen house and paddy
yield in the field correlated negatively with herbicide injury
while these (shoot dry weight at 12WAS and paddy yield) were
positively correlated with crop vigour, LA/plant, plant height
and tiller number/plant in both trials. No correlation was
observed between shoot dry weight, paddy yield and crop
emergence in both trials.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE AWARD OF THE
DEGREE OF MASTER OF SCIENCE IN AGRONOMY
DEPARTMENT OF AGRONOMY
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA.
NOVEMBER, 1998
Keywords
DIFFERENTIAL,, TOLERANCE., RICE., (Oryza sativa L.), CULTIVARS,, DIMETHAMETRYNE,