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Wheat Information
Service
Number 76: 32-34 (1993)
Effect of Septoria nodorum blotch on yield and size of processed
wheat seed
Bogdan Koric
Institute for Plant Protection, Zagreb, Croatia
Needs in wheat, a major bread cereal, have conditioned the
intensification of its production by introducing intensive cultural
practices. Such intensive wheat growing is creating problems in seed
production because of many diseases that directly or indirectly
effect sanitary seed condition. Detrimental effects of fungus
Leptosphaeria nodorum should be underlined, which cause
septoria nodorum glume blotch and attacks all above-ground parts of a
plant including seeds through spikes.
The effects of Septoria nodorum blotch in seed production of wheat is
manifested not only in lower yield due to reduced photosynthesis, but
also in poorer quality of the seeds--primarily its sanitary condition
and the size. Such problems encountered in seed production are the
main reason why we decided to investigate the effects of Septoria
nodorum blotch on yield, size and sanitary condition of the produced
seed.
Materials and methods
Field trial experiments were set following block design in
randomized blocks with five replications with the plot size of10
m2
using a variety
"Super Zlatna" for the treatments, shown as follows, at Botinec for
two years, 1989 and 1990.
1. Natural infection -- plots exposed to natural conditions of
growing (no artificial infection or fungicide application for disease
control)
2. Artificial infection -- plots exposed to natural conditions of
growing with artificial infection of a population of isolates of
Leptosphaeria nodorum fungus
3. Fungicide application -- plots exposed to natural conditions of
growing with artificial infection of a population of Leptosphaeria
nodorum and one treatment of a fungicide
All field trials were carried out under conditions of artificial
infection made at two intervals with collected, selected and tested
isolates of Leptosphaeria nodorum from Croatia region.
Artificial infection was made on 8th, 15th and 22nd of May, 1989 and
15th and 22nd of May, 1990. First application was made with a
population of selected isolates at flag-leaf stage (47 of Zadoks
scale), and repeated at full heading stage (59 of Zadoks scale)
(Zadoks et al 1974, Eyal et al 1987). One treatment of a fungicide
was applied with a backpack sprayer on 9th of May, 1989 and 15th of
May, 1990 at the growth stage of 51 (early heading stage).
For processing we used the line "Kamas" (processing machine) that has
screens with perforations of 2.5 mm. Calibration was made with an
average seed sample of 1 kg from each treatment on a calibrator with
perforations of 2.2 mm and 2.8 mm (Strona and Ubozenko1970).
Deep freezing blotter method was used for determining the percentage
of infection of Leptosphaeria nodorum into kernels (Mathur and
Lee Lilvia 1978).
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