Influence of pre-sowing seed treatment with bacterial agents on major elements of haricot bean yield structure

Abstract

Taking into consideration the direct dependence of seed yield and quality of haricot beans on combination of elements of its yield structure, we set an objective to evaluate effects of variety peculiarities and pre-sowing seed treatment with bacterial agents on major parameters of the yield structure under the conditions of the eastern forest-steppe of Ukraine.Materials and methods. The study was carried out in the Training, Research and Production Center “Opytnoye Pole" of Kharkiv National Agrarian University named after V.V. Dokuchaev in accordance with conventional methods in 2015–2017.The two-factor experiment was carried out by randomized replications in accordance with the complete factorial desing in four replicas. Three common haricot bean varieties (factor A) were studied during the experiment: 1 – Pervomaiskaia (control); 2 – Dokuchaievska; 3 – Panna. The plots of the second order (factor B) were the following variants of pre-sowing seed treatment with the bacterial agents: 1 – control (no seed treatment); 2 – Rhizobophyt (R); 3 – R+Phosphoenterin (Ph); 4 – R+Ph+Biopolicide; 5 – R+Ph+Aurill; 6 – cyanorhizobial complex.The weather conditions in 2015–2017 differed considerably in temperature and precipitation amount and distribution from the multi-year averages, and they approached the extreme values during certain periods. At the same time, this enabled more thorough investigation of the influence of the growing technology elements on the adaptation of haricot bean plants of changing abiothic factors. Considerable fluctuations in the main meteorological indices over the study years enabled more thorough evaluation of the effects of the studied elements on fulfillment of the genetic potential of seed yields in the haricot bean varieties of interest.Results and discussion. On average over the three years, the pre – sowing seed treatment with mixture of bacterial agents Rhizobophyt+Phosphoenterin+Aurill ensured the maximum seed weight per plant in all the varieties. The maximum seed weight per plant in this variant was due to a great number of beans per plant with slightly more plants per area unit. As to the seed number per raceme, this variant was similar to the others.It should be mentioned that new variety Panna had an advantage over other varieties in terms of the yield structure elements. The advantage of this variety was noticed in all the variants of pre-sowing seed treatment with bacterial agents. At the same time, differences between the seed weight per plant in the varieties under investigation were slightly smoothed over in the variants of complex pre-sowing seed treatment. For example, in the control (no seed treatment) the difference in the three-year average seed weights per plant amounted to0.99 gbetween Pervomaiskaia and Panna, however, after pre-sowing seed treatment with Rhizobophyt+Phosphoenterin+Aurill it only was0.38 g. The same tendency was noticed in the other variants.The maximum biological seed productivity was achieved in Panna after pre-sowing seed treatment with mixture Rhizobophyt+Phosphoenterin+Aurill. The essential advantage of this variant of pre-sowing seed treatment was seen in comparison with the control in all the years. Statistical analysis showed that in 2016 and 2017 this variant ensured a considerable gain in the yield in comparison with the other variants. The other variants of pre-sowing seed treatment with agent mixtures did not ensure a significant gain in the biological seed productivity of haricot beans in comparison with Rhizobophyt treatment.Conclusions. New variety Panna had higher values of the yield structure elements and higher biological seed productivity during all the study years. This variety is recommended for regions of the Eastern Forest-Steppe in Ukraine. To better fulfill the potential productivity of this variety, it is advisable to treat its seeds with agents Rhizobophyt+Phosphoenterin+Aurill at the recommended doses before sowing.