The effect of Terpal on the yield and yield components of oil-seed rape (Brassica napus L.)

Abstract

The objective of this study was to examine the effect of the chemical growth regulator Terpal (a mixture of mepiquat chloride and ethephon or 2 chloroethyl phosphonic acid) on the pattern of branching, plant height and yield components of winter oil-seed rape (cv. Jet Neuf). Mepiquat chloride (a quaternary ammonium compound with similar antigibberellin properties to cycocel) was developed as a morphoregulator for cotton where it has been shown to reduce plant height, shorten internodes and increase boll retention (Willard et al. 1977). The activity of ethephon has been attributed to its release of ethylene which influences a wide range of developmental processes, for example fruit abscission and ripening (Chatterjee, 1977; Gvozdenovic, Dulic & Slavic, 1978), growth retardation (Van Andel & Verkerke, 1978) and also the extent of lodging in cereals (Hill, Joice & Squires, 1982).

The effects of lodging and a paclobutrazol — chlormequat chloride mixture on the yield and quality of oilseed rape

“…Several studies on the use of PGRs in oilseed rape have been reported (Chapman, 1982;Daniels & Scarisbrick, 1986;Smith, 1987). These have tended to concentrate on the physiological effects induced by PGRs leading to effects on yield and its components (Chapman, Scarisbrick & Daniels, 1983;Scarisbrick, Addo-Quaye, Daniels & Mahamud, 1985; Addo-Quaye, . In wheat and barley, although the possibilities of inhibitors of gibberellin biosynthesis such as paclobutrazol (PP333) and chlormequat chloride causing changes in crop physiology beneficial to yield are well known (Humphries, 1968;Froggatt, Thomas & Batch, 1982;Waddington & Cartwright, 1986), recommendations for commercial use emphasise the benefits from the prevention of lodging (Anon., 19894.…”