A Preliminary Study of Soybean Genotype Responses to Glyphosate

Abstract

The effect of four application rates of glyphosate (Roundup, 360 g a.i./l) – 180; 360; 720 and 1440 g a.i./ha on the survival, dynamics of growth, and accumulation of fresh biomass in g per plant was studied on eight newly-developed Bulgarian lines, varieties and candidate varieties of soybean bred by different methods under greenhouse conditions. The objective of this study was to determine and compare the sensitivities of different soybean genotypes to glyphosate. The studied soybean genotypes showed different levels of glyphosate sensitivity due to their genetic differences. Glyphosate rates of 180, 360, 720 and 1440 g a.i./ha, applied at the stage of three trifoliate leaves (V4) of soybean had effect on the survival of the studied genotypes and can be presented conditionally in the following order: H (40.6%) < G (40.7%) < D (51.3%) < C (52.6%) < F (58.9%) < E (60.5%) < B (62.0%) < A (65.3%). The depression coefficients (B) of the studied characteristics depended mainly on soybean genotypes and the applied herbicide rates. The tested glyphosate rates showed a high (GI 26.5-51.6%) to relatively low degree of toxicity (GI 16.0-18.7%) in the studied soybean genotypes.

Proučavano je delovanje četiri doze primene glifosata (Roundup, 360 g a.m./l) – 180, 360, 720 i 1440 g a.m./ha na preživljavanje, dinamiku rasta i akumulaciju sveže biomase (g/biljci) osam novih bugarskih linija, varijeteta i predloženih varijeteta soje oplemenjenih različitim metodama u uslovima staklenika. Cilj proučavanja je bio da se utvrdi i uporedi osetljivost različitih genotipova soje na glifosat. Proučavani genotipovi soje pokazali su različite nivoe osetljivosti na glifosat kao posledicu genetskih razlika. Doze primene glifosata od 180, 360, 720 i 1440 g a.m./ha u fazi tri troliska (V4) soje su uticale na preživljavanje proučavanih genotipova i uslovno se mogu predstaviti sledećim redosledom: H (40.6%) < G (40.7%) < D (51.3%) < C (52.6%) < F (58.9%) < E (60.5%) < B (62.0%) < A (65.3%). Koeficijent opadanja (B) proučavanih karakteristika zavisi prevashodno od genotipa soje i doze primene herbicida. Ispitivane doze glifosata pokazale su stepen toksičnosti u rasponu od visokog (GI 26.5-51.6%) do relativno niskog (GI 16.0-18.7%) za proučavane genotipove soje.