Sedlak P.,Czech University of Life Sciences |
Vavra R.,Research and Breeding Institute of Pomology in Holovousy Ltd. |
Vejl P.,Czech University of Life Sciences |
Bocek S.,Mendel University in Brno |
Kloutvorova J.,Research and Breeding Institute of Pomology in Holovousy Ltd.
The apple scab caused by Venturia inaequalis is important apple disease in temperate zone. Economical losses caused by the pathogen are effectively reduced by intensive chemical protection and breeding. Occurrences of pathogen resistance to strobilurin fungicides were noted in some Czech orchards in the past. In 2007-2011, collection of 136 isolates V. inaequalis was tested with the aim to detect presence of single-point mutations of cytochrom b (cytb) gene causing efficacy loss of strobilurins. Consequently occurrence of beta-tubulin (beta-tub) gene mutation causing resistance to benomyl was studied with the aim to obtain comparative data about frequency of mutation in non-selective environment. Therefore simple and highly repeatable PCR based mutation detecting methods were optimised. Analysis brought knowledge about high similarity of cytb and beta-tub genes mutations occurrence. Whilst the frequency of the G143A substitution in cytb gene was 65% the E198A substitution of beta-tub gene occurred in 54% within pathogen population. This high frequency of resistant population necessitates revision of the way of strobilurins use in apple scab management. Source
Blazek J.,Research and Breeding Institute of Pomology in Holovousy Ltd. |
Paprstein F.,Research and Breeding Institute of Pomology in Holovousy Ltd. |
Krelinova J.,Research and Breeding Institute of Pomology in Holovousy Ltd.
Czech Journal of Genetics and Plant Breeding
The flowering onset of 19 apple progeny was evaluated in 2005–2014 on a total number of 715 seedlings in comparison with their parents and grandparents. A very low flower set delays generally the onset of flowering by one day in comparison with a higher flower set. The maximum span between the first flowering onset and the last one within all the progeny of the study was 11 days. With one exception, the incidence of the first flowering dates of all the progeny fluctuated only within four days–April 28 and May 1. Among them, the great majority of the seedlings had the first flowering date span of not more than ± one day. The progeny of Pink Lady × Discovery was the most exceptional having the mean day on the April 17 and the span about two days longer. The means of the first flowering dates within seedling populations and corresponding dates of both their parents and grandparents were very highly correlated (r = 0.926 for parents and r = 0.877 for grandparents). The incidence of flowering onset dates in almost all progeny followed a typical Gaussian distribution, in which the majority of seedlings start flowering within 3 or 4 days. The maximum difference between both extremes (found only in one progeny) was 11 days. The share of seedlings in both extremes was, however, very small–less than 2%. © 2015, Czech Journal of Genetics and Plant Breeding. All right reserved. Source