Articles
Minimising losses in radish (Raphanus sativus) at harvest due to splitting by manipulation of water availability during growth
Article number
1118_23
Pages
157 – 162
Language
English
Abstract
Hypocotyl splitting in radish (Raphanus sativus) is a problem for commercial growers as losses due to splitting can be up to 30%. The aim of this work was to investigate the effects of substrate water content during the secondary thickening phase on splitting at harvest.
Preliminary physiological studies have shown that the radish hypocotyl changes at the point when the hypocotyl begins to swell, this point is termed secondary thickening.
It is thought this may be an important period in development where the substrate water content affects the future growth and development of the hypocotyl.
During secondary thickening the outer exodermis and cortex rupture and slough away revealing the periderm which becomes the outer surface of the radish hypocotyl.
To determine if the substrate water content during secondary thickening affects levels of splitting at harvest the water content of the growing medium at this point was manipulated by withholding irrigation for different lengths of time and starting at pre-determined times prior to the onset of secondary thickening.
The amount of splitting at harvest was significantly greater at harvest (P<0.001) when substrate water contents were higher during the secondary thickening phase.
These results suggest substrate water status influences splitting during growth and radishes split less when they are exposed to low substrate water content at the point of secondary thickening.
Secondary thickening can be identified non-destructively in the field.
Preliminary physiological studies have shown that the radish hypocotyl changes at the point when the hypocotyl begins to swell, this point is termed secondary thickening.
It is thought this may be an important period in development where the substrate water content affects the future growth and development of the hypocotyl.
During secondary thickening the outer exodermis and cortex rupture and slough away revealing the periderm which becomes the outer surface of the radish hypocotyl.
To determine if the substrate water content during secondary thickening affects levels of splitting at harvest the water content of the growing medium at this point was manipulated by withholding irrigation for different lengths of time and starting at pre-determined times prior to the onset of secondary thickening.
The amount of splitting at harvest was significantly greater at harvest (P<0.001) when substrate water contents were higher during the secondary thickening phase.
These results suggest substrate water status influences splitting during growth and radishes split less when they are exposed to low substrate water content at the point of secondary thickening.
Secondary thickening can be identified non-destructively in the field.
Authors
R.A. Lockley, I.G. Grove, J.M. Monaghan
Keywords
hypocotyl, growth stage, hypocotyl expansion, volumetric water content, physiology
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