The influence of sowing dates on triticale photosynthesis in the Amur region conditions

Abstract

Abstract. In the Amur region the share of soybean in the structure of sown areas has reached 73.7 % over the last decade, the phytosanitary condition of agrocenoses has deteriorated, pesticide load on fields has significantly increased, which causes new ecological risks. Some reduction of this load may be caused by increasing the proportion of grain crops, including triticale. The purpose of the study was to establish the effective sowing date of spring triticale varieties providing optimal photosynthetic activity of agrocenoses in the conditions of Amur region. The method of field experiment by B. A. Dospekhov and determination of photosynthetic activity of crops by A. A. Nichyparovich were used. Scientific novelty. The photosynthetic activity of spring triticale varieties at different sowing dates in years with different meteorological conditions has been evaluated. Results. The greatest area of leaf apparatus is formed at sowing in April, 29 reaching maximum values in a phase of flowering in sort Ukro – 37,2 thousand m2/ha, in sort Yarilo – 30,4 thousand m2/ha, in sort Karmen – 33,0 thousand m2/ha. The correlation analysis revealed direct and strong influence of sowing dates on formation of the assimilative apparatus of plants and yield of spring triticale rxy = 0,833. Statistically significant differences were obtained p = 0.016. In the regression equation with increasing leaf area by 1 m2/ha the grain yield of triticale is expected to increase by 0.056 t/ha. Photosynthetic potential of the varieties differed in the years of research and depended on the value of the assimilating surface and the duration of the leaves. A regular decrease in net photosynthetic productivity from early to late sowing was established. The highest value of net photosynthetic productivity was obtained at sowing 15.04 – 2.03 g/m2 per day. The constituent elements of photosynthesis resulted in grain yields of the variety Yarilo – 2.26 t/ha, Ukro – 2.61 t/ha and Karmen – 2.23 t/ha.