Effect of a set of herbicides and the dates of their application to Triticum aestivum L. Cultivars on the content and yield of raw protein depending on the date of sowing
Dobrudzha Agricultural Institute – General Toshevo, 9521, General Toshevo, Bulgaria
Резюме
The investigation was carried out at DAI – General Toshevo during 2012 – 2014 in four-field crop rotation (wheat-maize-wheat-sunflower). Cultivars Aglika and Enola were sown on two dates – optimal (1st – 15th October) and late (after 20th November). The following set of herbicides was tested: Derby super VG – 3,3 g/da; Palace 75WG + oil – 25+100 g/ml/da; Granstar 75DF – 1,5 g/da; Lintur 70VG – 15 g/da; Husar Max ОD – 100 ml/da; Secator ОD – 10 ml/da and Mustang 306,25СК – 80 ml/da. The herbicides were applied on three dates: І date А – stage 29 according to Zadoks ; ІІ date B – stage 32 according to Zadoks and ІІІ date С – stage 37 according to Zadoks. The experiment included two check variants К1 – weed-free check (manually weeded from the emergence of the first weeds till heading of wheat), and К2 (nil) – a check infested till harvesting of the crop. A high level of significance was determined for the tested herbicides on the values of raw protein in grain and protein yield from the tested cultivars under the conditions of the experiment. The years of investigation had highest effect on the values of the tested characteristics. Best results were obtained in 2012. At the late date of herbicide application, the amount of protein decreased in both cultivars. Averaged for the investigated period, the size of protein yield of cultivar Enola was with 18.7 % higher than the yield of cultivar Aglika.
In all three years of the investigation, highest yield of raw protein was obtained from the manually weed-free check (К1) and lowest – from the infested check (К2). Averaged for the tested variants of the trial, only after the application of the herbicides Derby super VG and Secator OD the raw protein yield remained at the level of the weed-free check (К1). There was a strong positive correlation of grain yield with raw protein yield. Averaged for the period of investigation, the sowing date of cultivar Aglika did not show significant effect on the values of the correlation coefficients. In cultivar Enola, the late sowing date lead to high increase of the correlation. This tendency was best expressed in harvest year 2014 (r=,875**).
Key words: Wheat, Cultivars, Dates of sowing, Herbicides, Stages of application