Impact of mixtures between retardants and combined herbicides on the sowing properties of the durum wheat

G. Delchev

Abstract. The research was conducted in 2007-2009 on the experimental field of the Field Crops Institute, Chirpan, Bulgaria, on pellic vertisol soil type. Factor A included no treated check and 5 retardants – Stabilan (chlormequat) – 2 l/ha, Flordimex extra (ethephon) – 750 ml/ha, Vivax (chlormequat + ethephon) – 1.7 l/ha, Cycocel extra (chlormequat + cholinechloride) – 1.5 l/ha, Terpal (ethephon + mepiquat) – 3 l/ha. Factor B included weeded no treated check and 3 herbicides – Hussar max (mesomax + iodosulfuron) – 250 g/ha, Logran extra (terbutrin + triasulfuron) – 500 g/ha, Glean (chlorsulfuron) – 15 g/ha. All retardants, herbicides and their tank-mixtures were treated in tillering stage of the durum wheat. The weak adhesion of Hussar max required its application with adjuvant Genapol in dose 500 ml/ha. Under investigation was Bulgarian durum wheat cultivar Progress, which belongs to var. leucurum.Tank mixtures of herbicide Logran extra with retardants Stabilan, Vivax and Cycocel extra, of herbicide Glean with retardant Flordimex extra and of herbicide Granstar with retardant Terpal have decreased the germinative energy of durum wheat sowing seeds. Investigated retardants, combined herbicides and their tank mixtures do not influence seed germination and waste grain quantity. Tank mixtures Flordimex extra + Hussar max and Flordimex extra + Logran extra have decreased root and coleoptile length. Mixtures of Glean with the investigated retardants have increased root and coleoptile length. Herbicide Logran extra cannot be mixed with retardants containing chlormequat – Stabilan, Vivax and Cycocel extra. There is antagonism in mixtures of Hussar max with Flordimex extra and Glean with Terpal.