Photosynthetic Pigments Content in Emmer Wheat Plants as Criteria of Productivity in Traditional and Organic Farming Technology

Abstract

Background. Estimation of chlorophyll and carotenoid content is an informative way to obtain ideas about the plants photosynthetic process and is an indirect method for assessing the productivity of plant crops, including cereals. As the worldwide interest at now for traditional and natural foods is growing, in the work we used one of the oldest grain crops – emmer wheat (Triticum dicoccum (Schrank.) Schuebl.) which was cultivated in traditional and organic farming system. Objective. The study aim was to determine the role of chlorophyll and carotenoids in the emmer wheat productivity formation by traditional and organic farming technology under different pre-sowing seed treatment systems. Methods. Field experiment was establishment during 2019–2021 on low-humus, hard-loam chernozems, the condition of which meets the “virgin land” criterion. The emmer wheat cultivation in organic technology was carried out in crop rotation: winter rye (green manure crop) – mustard (to improve the field phytosanitary condition and soil organic matter indicators) – emmer wheat. Two variants of pre-sowing seed treatment were studied: irradiation with ultraviolet light of the C range (100–280 nm) and seed treatment with 1r Seed Treatment humic preparation. The pre-sowing seed treatment in the traditional technology of the emmer wheat cultivation was carried out by the UV-C irradiation. In organic technology both UV-C irradiation and treatment with 1r Seed Treatment humic preparation of natural origin were used. Statistical data processing was performed by methods of descriptive statistics, regression and analysis of variance by the program Statistica 10.0. The experimental data significance was evaluated by using multifactor analysis of variance (ANOVA) to calculate the least significant difference (LSD05). Results. It was found the use of UV-C seeds irradiation in organic and traditional cultivation technologies leads to increase in the chlorophyll a (Chl a) content by 9.2 % and chlorophyll b (Chl b) content by 14.5 % in plants grown by organic technology, however to decrease in carotenoid content (Ct) by 14.9 %. The increase in the photosynthetic pigments content by UV-C seeds irradiation lead to yield increase from 4.26 t/ha by the traditional technology to 5.17 t/ha by the organic technology, ie by 21.4 %. In organic technology based on the comparison of the photosynthetic apparatus main indicators of the emmer wheat and yield, the most effective method for seed treatment was determined. It was established that at result of 1r Seed Treatment humic preparation application in pre-sowing seed treatment, the Chl a concentration decreased by 2.4 %, the Chl b and Ct concentration increased by 5 and 25.5 %, respectively, compared with plants grown from UV-C irradiated seeds. When 1r Seed Treatment was used for pre-sowing treatment yield was 5.58 t/ha, while at UV-C seed treatment – 5.17 t/ha, ie, the yield increase was 8 %. An inverse correlation between the ratio of the photosynthetic pigments Chl a/Chl b content and the emmer wheat yield was determined. Conclusions. According to the study results, it can be assumed that the introduction of organic farming technology with pre-sowing seed treatment by the 1r Seed Treatment humic preparation can increase the emmer wheat yield by 31% compared to the traditional technology. Thus, the photosynthetic pigments content and their ratio can be the effectiveness indicators of the implemented agricultural technologies.