Potencial alelopático de trigo sobre a germinação e crescimento de plântulas em cultivares de soja

Abstract

In the current scenario of valuation of soil conservation, the cultivation of wheat have been shown as a profitable alternative to the cold season of the year, previous forms of soil management, such as fallow. However, the insertion of wheat in the successional rotation scheme with soybean may have undesirable effects, caused by wheat's ability to produce secondary compounds, known as allelochemicals. The objective of this study was to evaluate the allelopathic potential of wheat on soybean cultivars, under laboratory conditions. For this, the experiment was carried out at the Plant Physiology Laboratory of the Universidade Federal da Fronteira Sul (UFFS) – Campus Cerro Largo, in the period of July-August / 2018. Experiments on germination (25 seeds per Experimental Unit - UEs) and seedling growth (3 seeds pre-germinated by UEs) were carried out*. The crude aqueous extract was obtained from flowering plants, composed of roots, leaves, stems and spikes, still without grain formation. The crude aqueous extract was obtained from flowering plants, composed of roots, leaves, stems and spikes, still without grain formation. A completely randomized design (CI) was used in a 1 x 4 x 4 factorial scheme, a wheat genotype (TBIO Sinuelo), four soybean cultivars (BMX Magna RR / C1, DM 5958 IPRO / C2, NA 5909 RG / C3 and NS 6909 IPRO / C4) and four concentrations of wheat extract (0, 25, 50 and 100%), with three replicates, totaling 48 EUs. For the germination, the average percentage of germination and speed of germination was analyzed. Regarding the seedling growth experiment, the occurrence of normal and abnormal seedlings, length and dry mass of radicle and shoot were evaluated. The data were compared by analysis of variance (ANOVA) with the aid of the statistical program SASM-agri and submitted to regression analysis, with adjustment by electronic spreadsheet. In view of the results obtained, the cultivar C4 presented greater susceptibility to the aqueous extract of wheat, since, in the concentration 100%, the germination was null. Already C3, despite the great implications, was shown to be least affected by the allelochemicals released by wheat. The other cultivars show intermediate behavior compared to the previous cultivars. With this, it was observed that there was an allelopathic effect of the aqueous wheat extract on all tested soybean cultivars, visualized through the reduction of germination percentage and seedling growth.