Periods of interference of Alexandergrass on morphophysiological and productive characteristics of transgenic soybean
Leandro Galon, Alessandro Konzen, Hugo Von Linsingen Piazzetta, Germani Concenço, Maico André, Michelon Bagnara, Antonio Marcos Loureiro da Silva and Gismael Francisco Perin
Universidade Federal da Fronteira Sul, Erechim, RS, Brasil.
Abstract
Among the weed species infesting soybean, Alexandergrass (Urochloa plantaginea) is highlighted as one of the most competitive. The objective of this work was to determine the periods of interference of Alexandergrass, and is effects, on morphophysiology and yield components of soybean. Treatments were pooled into two groups: the group “convivence” comprised soybean growing among Alexandergrass for increasing periods: 0, 7, 14, 21, 28, 35 and 42 days after emergence (DAE), as well as along all the crop cycle. The “control” group comprised soybean free from competition for the same time lapses. Forty-two DAE, soybean morphophysiology was assessed. There was no effect of the time lpse of Alexandergrass “control” or “convivence” on soybean physiological performance. Plant height, stem diameter, plant dry mass, leaf area and grain yield components of soybean were, however, affected by Alexandergrass. The critical period of interference prevention comprises 26-41 DAE; the period prior to interference is 26 DAE; and the total period of interference prevention is 41 DAE.
Highlighted Conclusions
1. The yield components of soybean are negatively affected by Alexandergrass (Urochloa plantaginea) interference.
2. The control and coexistence periods of Alexandergrass did not change the physiological traits of soybean plants.
3. The critical periods of interference of Alexandergrass in competition with soybean were 26, 41 and 26 – 41 days, respectively for PAI, PTPI and PCPI.