Tolerância de genótipos de cana-de-açúcar a herbicidas / Sugarcane genotypes tolerance to herbicides

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The objective of this study was to evaluate the tolerance of sugarcane genotypes to herbicides ametryn, trifloxysulfuron-sodium and their formulated mixture (ametryn + trifloxysulfuron-sodium). Two experiments were conducted, one under greenhouse conditions and the under field conditions, at the Centro Experimental de Pesquisa da Cana-de-açúcar da Universidade Federal de Viçosa, located 2020S e 4348W in the city of Oratórios-MG. In the greenhouse experiment, which aimed to evaluate the tolerance of genotypes SP80-1816, RB855113 and RB867515, treated with four doses of herbicides (0.0, 0.5, 1 and 3.0 times the recommended for the crop), it was used a completely randomized design, with four replications. Evaluations of plant intoxication by herbicides were performed at 14, 28 and 42 days after treatments application and the effects of the herbicides on the leaf area and shoot dry matter were measured at 80 days after the buds shoot. In the second test, conducted in the field, it was used an infrared gas analyzer (IRGA) 85 days after planting, to assess the effects of ametryn (2.000 g ha- 1), trifloxysulfuron-sodium (22.5 g ha-1) and ametryn + trifloxysulfuron-sodium (1463 + 37.0 g ha-1) on the characteristics related to photosynthetic activity in the sugarcane genotypes (RB72454, RB835486, RB855113, RB867515, RB947520 and SP80-1816). In this same trial, it were also evaluated effects of the herbicides in ten genotypes, the six cited above, plus RB855156, RB925211, RB925345 and RB937570 on the components of productivity and raw matter quality of sugarcane. This experiment was conducted in a split plot design with four replications. For the greenhouse trial, genotype RB855113 was the most sensitive to all herbicides and applied doses, followed by the SP80-1816. The most tolerant genotype to all herbicides was RB867515. For the field experiment, the herbicide ametryn caused more damage to the sugarcane genotypes photosynthesis when compared to other herbicides. The trifloxysulfuron-sodium and the commercial mixes also caused differentiated intoxication, being RB855156 the most sensitive genotype and SP80-1816 the most tolerant. Genotype RB855156 stalks and sugar productivity were more affected by the herbicides, specially by trifloxysulfuron-sodium. This one also caused negative effects in the productive characteristics of the genotype RB835486. Genotype RB855113 stalks and sugar productivity was influenced negatively under the action of ametryn + trifloxysulfuron-sodium. It follows that the sugarcane genotypes showed differential tolerance to ametryn, trifloxysulfuron-sodium and their mixture ametryn + trifloxysulfuron-sodium, independently of the doses. Thus, it should be taken care when using these products, specially when choosing the genotype to be cultivated.

ASSUNTO(S)

saccharum spp krismat tolerance trifloxysulfuron-sodium ametryn fitotecnia tolerância ametryn saccharum spp krismat trifloxysulfuron-sodium

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