The Influence of Plant Growth Regulators on Morphological Indexes and Performance of Brassica juncea L. in the Forest-Steppe of Ukraine

Abstract

Plant growth regulators have a great impact on agricultural production, but an application of the conventional application mode has certain restrictions on the growth and yield improvement. The subject of the study is Brassica juncea L. varieties (Prima and Felicia), methods of application and types of plant growth regulators, weather conditions, yield, and quality seeds for the cultivation in terms of the Left-Bank Forest-Steppe of Ukraine. The seed yield capacity of Felicia (1.78 t/ha) was significantly higher than that of Prima (1.67 t/ha). All growth regulators increased the average 1000-grain weight of both varieties. For Prima, the influence of Fast Start and Regoplan on 1000-grain weight reached the maximum value, which was 9.5%, except for Albit and Vermistim D. The other growth regulators significantly increased Felicia's 1000-grain weight from 5.8% to 11.7%. The application of growth regulators increased the average oil content from 1.18% to 5.61%. As the result of correlation analyses, seed yield had positive and highly significant (p < 0.01) correlations with the number of pods per plant, the number of branches per plant, leaf area, and the average seed weight per plant. The 1000-seed weight was a positive highly significant (p < 0.01) association with the chlorophyll content and the plant height. These results showed that the branch number, yield per plant, pod number, and leaf area were the main factors determining yield capacity in both varieties. The oil content was negatively correlated with protein.