Time filter

Source Type

Aschersleben, Germany

Romer P.,GHG Saaten GmbH | Grosch R.,Leibniz Institute of Vegetable and Ornamental Crops | Kofoet A.,Leibniz Institute of Vegetable and Ornamental Crops | Farahani-Kofoet R.D.,Leibniz Institute of Vegetable and Ornamental Crops
Acta Horticulturae | Year: 2010

Downy mildew (Peronospora sp.) on basil can cause tremendous damages and financial losses in fresh herb production. Chemical control is crucial due to the risk of chemical residues in the plant matter. In a joint project between the German herb breeding company GHG Saaten GmbH and the Institute of Vegetable and Ornamental Crops (IGZ) the conditions for optimal infection with Peronospora sp. on basil have been successfully identified and resistant genotypes have been found. However, these belong to wild Ocimum species. A long term cross breeding programme is necessary to combine both downy mildew resistance and basil of the "Genovese" type which is required by the consumers. The second part of the project is the search for basil genotypes tolerant to cold temperatures. Producing at lower temperatures could save a lot of energy costs. Breeding lines and varieties of different basil types have been grown at 17°C instead of 20°C to 22°C in growth chamber. One breeding line of the "Genovese" type has been found to be tolerant against lower temperature conditions. However, this line needed about 17 days longer to reach the stage of marketability at 17°C. Recent trials at 18°C including new breeding lines revealed genotypes with similar growth compared to the check varieties grown in the warm glasshouse.

Djalali Farahani-Kofoet R.,Leibniz Institute of Vegetable and Ornamental Crops | Romer P.,GHG Saaten GmbH | Grosch R.,Leibniz Institute of Vegetable and Ornamental Crops
Scientia Horticulturae | Year: 2014

Downy mildew on sweet basil (Ocimum basilicum), caused by Peronospora belbahrii, has become a serious problem worldwide. In Germany, approximately 50 million pots with basil are produced annually on more than 25ha of greenhouses. There are a few registered fungicides for the control of basil downy mildew. Increasing concern about the health and environmental hazards associated with the use of fungicides has intensified the need for mildew-resistant plants. A resistance screening method was established that allows a rapid selection of P. belbahrii resistant Ocimum genotypes under reproducible and favorable conditions for disease development. First, experiments were carried out to determine the optimal conditions for infection and further disease progress. Sporangia germination was favored between 5°C and 15°C in vitro. Freshly harvested sporangia germinated at nearly 90% in contrast to a germination rate of up to 25% observed for frozen sporangia. However, inoculation of basil plants with 3×104 fresh or frozen sporangia mL-1 resulted in high disease severity 14 days post-inoculation (dpi). A temperature of 20°C was revealed as optimal for both infection of basil with P. belbahrii and sporulation of the pathogen on basil leaves at high relative humidity. For evaluating resistance of basil genotypes against downy mildew, basil plants at the 4-leaf-stage were inoculated with sporangia suspension (3×105 frozen sporangia mL-1) and incubated for 24h at 20°C and 100% humidity in the dark. Afterward the plants were cultivated at 23/18°C and 60/80% relative humidity with a 12h/12h day/night light-cycle. Before disease severity was assessed 5 to 14dpi, plants were incubated for 18h at 20°C in the dark at nearly 100% relative humidity. Using these conditions, we assessed the susceptibility of 236 Ocimum genotypes against downy mildew. The genotypes O. americanum var. americanum/O. canum, O. americanum×basilicum 'Blue Spice', O. americanum var. pilosum, O. campechianum/O. micranthum 'Peruvian basil', O. gratissimum and, O. tenuiflorum 'Tulsi' showed resistance to downy mildew. However, they represented exotic basils, differing greatly in plant morphology, aromas and taste. These resistant genotypes could become potential sources for further breeding of basil cultivars resistant to P. belbahrii. © 2014 Elsevier B.V.

The production of basil in pots for the fresh herb market requires high temperatures (20 °C to 22 °C) in the greenhouses which is very energy consuming, especially during the winter months. Producing at lower temperatures could save a lot of energy costs. The German breeding company GHG Saaten GmbH (Aschersleben) is participating in a project which is financially supported by the Federal Ministry of Food, Agriculture and Consumer Protection. The aim is to select basil varieties tolerant to low temperatures. Breeding lines and varieties of the so called "Genovese" type - which is mainly grown for fresh herb production - and red-, small and lettuce-leaved basil types have been grown in a climate chamber at 18 °C (day and night). Breeding lines of the "Genovese" type have been selected which had a similar development under cooler conditions compared to the control varieties grown in the warmer (22°C day/18 °C night) greenhouse. © Agrimedia GmbH & Co KG 2010.

Good seed quality is an important prerequisite for the successful production of aromatic plants. The main characters are purity, germination capacity and seed health. The investigation of these should be done and attested by ISTA-accredited laboratories and official plant protection labs. The seed quality of most species of aromatic plants is exclusively under the responsibility of the seed trader. At the suspicion of defects in seed quality the first thing to do is to check the cultivation conditions of the crop. If these can be excluded as the source of the problem the re-examination of the seeds may be necessary. The correct way of seed sampling is essential in order to get a result which is representative for the whole lot.

Djalali Farahani-Kofoet R.,Leibniz Institute of Vegetable and Ornamental Crops | Romer P.,GHG Saaten GmbH | Grosch R.,Leibniz Institute of Vegetable and Ornamental Crops
Mycological Progress | Year: 2012

Downy mildew on sweet basil (Ocimum basilicum L.) occurs worldwide. Contaminated seeds are considered as the primary inoculum source. So far no strategy to control the disease is available. Hence, the use of pathogen-free seeds is the only alternative to prevent disease outbreaks. Therefore, a rapid diagnostic method for seed testing is urgently needed. The sensitivity of a specific PCR method for direct detection of the downy mildew pathogen Peronospora belbahrii on basil samples, particularly on seeds, was evaluated. The applied PCR method proved to be very sensitive for direct detection of the pathogen on seeds and plant samples. The PCR detection limit of P. belbahrii in artificially infested seeds corresponded to the DNA amount of a single spore per seed. Additionally, the systemic spread of the pathogen from naturally infected seeds was investigated. The experiments showed that outgrowing basil plants were latently infected with the downy mildew pathogen, and the infection continued within the plant. Contaminated seeds were harvested from symptomless latently infected plants. These results support the implementation of PCR-based detection in a seed certification scheme and the necessity to control the pathogen on seeds. The PCR method can also be used for evaluation of pathogen control on seeds based on detection of the pathogen in outgrowing plants. © 2012 German Mycological Society and Springer.

Discover hidden collaborations