Abstract
Photosynthetic pigments play an important role in the accumulation of dry matter and they can be the markers of stress. Change in the ratio of chlorophyll A and B indicates physiological changes and adaptation of the organism to changes of environmental conditions. Sowing terms and application of nitrogen fertilizers are long-term factors, so the content of chlorophylls in the flag leaf indicates long-term adaptation of the photosynthetic system. Establishing a relationship between the chlorophyll content at anthesis and the accumulation of dry matter in posy-anthesis period indicates the varietal response of triticale to fertilization and sowing dates. It was conducted a three-factor field experiment. There are studied two winter and one facultative triticale cultivar, two autumn sowing terms and fertilization system with application the different rates of nitrogen fertilizers in different growth stages. It was found that the content of photosynthetic pigments in each variety varied depending on sowing term and fertilizer system in terms of mg per 1 g of dry matter for chlorophyll A, B and the amount of A+B. At the same time, the difference between the factors and their interactions was insignificant for the total chlorophyll mass per unit area (g/m2) for chlorophyll A and the amount of A+B, but it was significant for chlorophyll B by the fertilizer system factor. This indicates that the main stress signal is chlorophyll B, so the ratio of chlorophyll A and B differed significantly depending on this factor. Cla: Clb ratio in the optimal sowing period is 5.3–8.1 in cv. Pidzimok kharkivskiy, 4.8–8.3 in cv. Amur and 5.0–6.7 in cv. Obriy mironivskiy. All cultivars have a strong positive correlation between the chlorophyll content at anthesis and accumulation of dry matter at post-anthesis perion under optimal conditions, but facultative triticale Pidzimok kharkivskiy has a negative correlation with unfavorable, due to increased chlorophyll, without increasing dry matter accumulation. Further study of the relationship between chlorophyll content and the synthesis of primary and secondary metabolites is promising in the study of varietal response to stress and agronomic factors.