Incidência de podridões do colmo, grãos ardidos e rendimento de grãos em híbridos de milho submetidos ao aumento na densidade de plantas

Abstract

The combination between plant density and hybrid choice is an important factor to enhance maize grain yield. The objective of this work was to evaluate the increasing of plant density on the incidence of stalk rot, rot grains and grain yield of two maize hybrids with contrasting tolerance to crowding. The experiment was carried out in Lages-SC, during the crop seasons of 2002/03 and 2003/04, in an area of no-tillage and monoculture, having a mixture of black oat and vetch as the preceding winter crop. The experimental design was a randomized block with split plot arrangement and three replications per treatment. Two hybrids were evaluated in the main plots: Speed (a single-cross hybrid tolerant to crowding) and AG 303 (a doublecross hybrid intolerant to crowding). Each hybrid was submitted to Casa, R.T.; Moreira, E.N.; Bogo, A.; Sangoi, L. Incidence of stalk rot, rot grains and grain yield of maize hybrids submitted to the increase in plant density Summa Phytopathologica, v.33, n.4, p.353-357, 2007. five plant densities in the split-plots: 25, 50, 75, 100 and 125 thousand plants per ha. The increase in plant density enhanced linearly the occurrence of stalk rot and rot grains for both hybrids and crop seasons. The fungus Colletotrichum graminicola was detected with great frequency in the stalk rot, regardless of hybrid and crop season, followed by Fusarium graminearum, F. verticillioides and Stenocarpella sp. The predominant fungi in rot grains were F. verticillioides, F. graminearum and Penicillium spp. The grain yield of AG 303 was less responsive to the increment in plant density. No association between the higher grain yield of the single-cross hybrid Speed at dense stands and the lower incidence of stalk rot and rot grains was detected. RESUMO

Maize and soybeans production in integrated system under no-tillage with different pasture combinations and animal categories

“…Damaged kernels percentage observed in this experiment are consistent with those reported in Casa et al (2007). Maize population and yield are according to characteristics of hybrid that are higher than national averages.…”

Períodos de interferência de plantas daninhas na cultura da cenoura em função do espaçamento entre fileiras

“…Para um mesmo cultivar, a produtividade das culturas geralmente se eleva com o aumento de densidade de plantas até que um ou mais fatores (condições edafoclimáticas ou práticas culturais) se tornem limitantes. Em outras culturas, diversas pesquisas evidenciaram que espaçamentos menores propiciam maiores rendimentos, devido ao aproveitamento mais eficiente da radiação solar, da água e dos nutrientes, além da menor interferência das plantas daninhas, como consequência do fechamento mais rápido do dossel vegetativo (Parvez et al, 1989;Brizuela, 1994;Braz, 1996;Murphy et al, 1996;Casa et al, 2007).…”

Physiological and sanitary quality of maize seeds treated with biological control agents

“…Diplodia macrospora Earle] are highlighted, with the latter being often detected in Brazil's maize crops , Wordell Filho et al, 2010, Casa et al, 2011. The fungus F. verticillioides is also associated with cob rot, which results in reduced grain yield and quality, besides causing decrease in product price (Casa et al, 2007).…”