A survey to determine the influence of grain moisture (Gm) of spikelets, time of harvest and climatic conditions, with particular attention to rainfall, on Head Rice Yield (HRY) at the milling of paddy rice was carried out over six years. The survey was conducted on seven varieties of japonica spp. characterized by different dimensions of caryopsis (ratio length/width) and the presence or absence of seed pearl. The humidity of the spikelets situated in the apical, central and basal zones of the panicle was determined weekly for a period of about two months so as monitor the process of ripening and demonstrate the extent of difference. During the six years of observation, notable differences were seen in the frequency and intensity of rainfall, while variations in temperature and relative humidity of the air were slight. Even in the most favourable cases, the average humidity of the paddy never fell below 15% (w.b.). It was also noticed that, for varieties with a round caryopsis and with the presence of a large pearl, a reduction of about 6-8% of HRY takes place only when the harvest and subsequent drying follows a re-humidification of the paddy rice after repeated rainfall of at least two days or which as an intensity above 15 mm. This reduction is greatly decreased or not observed if the harvest is delayed at least 24 hours after the rainfall and the drying air is at 30°C. Varieties with a caryopsis without pearl and with a ratio length/width near of greater than 3, are less sensitive to the phenomenon. On the strength of these results, it was concluded that the climatic conditions which exist in the Po Valley do not induce notable reduction in HRY following the re-humidification by rainfall as drying in the field never reaches the critical values reported in the literature.

The effect of the weather on the whole kernel yield at milling processing of selected cultivars of Oryza sativa L. grown in Italy in the Po Valley

VIDOTTO, Francesco
2002-01-01

Abstract

A survey to determine the influence of grain moisture (Gm) of spikelets, time of harvest and climatic conditions, with particular attention to rainfall, on Head Rice Yield (HRY) at the milling of paddy rice was carried out over six years. The survey was conducted on seven varieties of japonica spp. characterized by different dimensions of caryopsis (ratio length/width) and the presence or absence of seed pearl. The humidity of the spikelets situated in the apical, central and basal zones of the panicle was determined weekly for a period of about two months so as monitor the process of ripening and demonstrate the extent of difference. During the six years of observation, notable differences were seen in the frequency and intensity of rainfall, while variations in temperature and relative humidity of the air were slight. Even in the most favourable cases, the average humidity of the paddy never fell below 15% (w.b.). It was also noticed that, for varieties with a round caryopsis and with the presence of a large pearl, a reduction of about 6-8% of HRY takes place only when the harvest and subsequent drying follows a re-humidification of the paddy rice after repeated rainfall of at least two days or which as an intensity above 15 mm. This reduction is greatly decreased or not observed if the harvest is delayed at least 24 hours after the rainfall and the drying air is at 30°C. Varieties with a caryopsis without pearl and with a ratio length/width near of greater than 3, are less sensitive to the phenomenon. On the strength of these results, it was concluded that the climatic conditions which exist in the Po Valley do not induce notable reduction in HRY following the re-humidification by rainfall as drying in the field never reaches the critical values reported in the literature.
2002
2nd Temperate Rice Conference
Sacramento (Ca, USA)
13/06/1999-17/06/1999
Proceedings 2nd Temperate Rice Conference
International Rice Research Institute (IRRI)
471
479
9789712201806
A. Finassi; P. Noris; F. Vidotto
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/86846
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