Effect of planting density of maize on the progress and spread of northern leaf blight fromExserohilum turcicum infested residue source

Abstract

Effect of plant density (37,037, 44,444 and 55,555 plants/ha) on the increase of northern leaf blight in time and space on two maize cultivars planted at spacings of 90, 75 and 60 between rows and 30 cm within rows was investigated. Exserohilum turcicum infested maize residue was used as an inoculum source. Maize density did not significantly affect the disease indices, but significantly influenced the grain yield of the two cultivars. In contrast, the two cuitivars differed significantly (P < 0.01) in disease severity, but not grain yield. Higher disease severities and grain yields were associated with higher plant densities, whereas the apparent infection rate was lower in higher plant density. Distance from the maize residue (inoculum source) significantly influenced disease severity. The percentage leaf area blighted, area under disease progress curve and disease progress curve intercept decreased with distance from the maize residue area, but the apparent infection rate on EV8429-SR appeared to increase with distance. Disease gradients (b) were higher in closely planted maize and flattened with time in one location only.

Effect of Cercospora zeae‐maydis infested maize residue on progress and spread of grey leaf spot of maize in central Uganda

“…The disease gradients varied significantly with year and location, being high in the second season and low in the first season of 2000 and second season of 1999, but were generally higher compared to those reported in other pathosystems (Lipps, 1988;Adipala et al, 1995) and on maize under temperate climatic conditions in Ohio, USA (de Nazareno et al, 1993b). According to Gregory (1968), secondary spread, background contamination or proximity to a large area of inoculum causes flattening of the primary gradient.…”

“…The Gompertz model, ln(-ln(y)) = -ln(-lny) +rt (Berger, 1981), was also fitted to the pooled data from the four replicates. These models were selected because of their common usage and because most previous studies indicated their suitability (de Nazareno et al, 1993a,b;Takan et al, 1994;Adipala et al, 1995). Similarly, the exponential, y = a exp(-bx) (Kiyosawa & Shiyomi, 1972), and the power law model, y = ax b (Gregory, 1968), were fitted to the pooled data from the four replicates.…”

Qualitative and Quantitative Trait Polymorphisms in Maize

“…Northern leaf blight is a serious foliar disease of maize in the Northeastern United States, in sub-Saharan Africa, Latin America, China, and India (Adipala et al 1995;Dingerdissen et al 1996). A number of dominant or partially dominant major genes have been discovered conferring race-specific resistance to NLB, including Ht1 (Hooker et al 1963), Ht2 (Hooker 1977), Ht3 (Hooker 1981), Ht4 (Carson 1995), Htn1 (Gevers 1975), HtP (Ogliari et al 2005), and Bx (Couture et al 1971).…”

Mapping QTLs for resistance to Northern Leaf Blight in Tropical Maize (Zea mays L.)

“…NCLB is common in areas that have high humidity combined with moderate temperatures in the northeastern United States, in sub-Saharan Africa and in areas of China, Latin America, and India (Adipala et al, 1995 andDingerdissen et al, 1996). In India, the disease is prevalent in Karnataka, Andhra Pradesh, Tamil Nadu, Bihar, Himachal Pradesh, Maharashtra and other regions (Harlapur et al, 2000).…”