Sunil K M

Crops weather relationship in rice - Vellanikkara Department of Agricultural Meteorology, College of Horticulture 2000



An experiment was conducted in the Agricultural research Station,
Mannuthy during first, second and third crop seasons of 1998-99 to study the crop
weather relationship in rice variety 'Kanchana'. The experiment was laid out in
randomised block design with three replications. The treatment consisted of three
dates of planting in each season i.e., 1 s\ i s" and 30th of June, 1 st 15th and 30th of
October and 1 st, 15th and 30th of January.
Observations on morphological and yield attributes were recorded during
the course of investigation. The daily values of weather elements viz., maximum and
minimum surface air temperature, bright sunshine, morning and afternoon relative
humidity and wind speed were collected from the Principle Agro Meteorological
Station, College of Horticulture, Vellanikkara, to work out the crop weather
relationships in rice.
. Crops transplanted on 1 st is" and 30tl) of October and 1 st 15th of June
were significantly superior in terms of grain yield, panicle number, number of filled
grains/panicle, number of leaves, plant biomass, number of tillers and leaf area
index.
The crop weather relationship studies showed that the wind speed,
minimum temperature and mean temperature during flowering to maturity had a
significant negative correlation with grain yield. But morning relative humidity and
mean relative humidity during transplanting to panicle initiation stage had a
significant positive influence on ultimate grain yield.
The wind speed, mean temperature, temperature range, RH1-RH2 and
solar radiation during vegetative stage were negatively correlated with the straw
yield. Maximum temperature during beginning of grain filling to maturity stage also

had a negative correlation. But increase in mimmum temperature, mean relative
humidity, morning and afternoon relative humidities during transplanting to
flowering stage was significantly increase the straw yield as there was a positive
correlation.
The regression equations developed in the study predicted the grain yield,
straw yield, duration of vegetative phase and maximum leaf area index well and a
close relation existed between observed and estimated yield.
Based on the experimental data, minimum data set for the validation of
rice model of the IBSNAT has been generated.



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