Resistance tests of interspecific hybrids of the tribe Brassiceae to infection caused by the Leptosphaeria sp. and Alternaria sp.

W pracy przedstawiono wyniki badań dotyczące odporności mieszańców międzygatunkowych z plemienia Brassiceae na porażenie powodowane przez patogeny Leptosphaeria sp. oraz Alternaria sp. Przedstawiono problematykę dotyczącą wytwarzania mieszańców międzygatunkowych techniką in vitro. Otrzymano 159 zarodków mieszańców międzygatunkowych, z których 52 genotypy klonowano in vitro i in vivo dla otrzymania roślin w większej wydajności. Poszukiwano genotypów z plemienia Brassiceae odpornych na porażenie powodowane przez Leptosphaeria sp. oraz Alternaria sp. Przebadano 49 obiektów, z których mała część wykazywała podwyższoną odporność na oba patogeny. Wykonano także analizy DNA dziesięciu patogenów użytych do inokulacji. Badano także odporność siewek (indeks porażenia dla 12 obiektów) otrzymanych z mieszańców międzygatunkowych oraz roślin kontrolnych i donorowych rzepaku, na porażenie powodowane przez patogeny z rodzaju Leptosphaeria oraz Alternaria. U wybranych genotypów odnotowano niski indeks porażenia (IP) i te formy przekazano do dalszej hodowli odpornościowej.The paper presents the results of studies on resistance of interspecies hybrids from the Brassiceae caused by Leptosphaeria sp. and Alternaria sp. pathogens. 159 intercross hybrid genomes were obtained, of which 52 genotypes were cloned in vitro and in vivo. The genotypes were searched from the Brassiceae less resistant to infestation by Leptosphaeria sp. and Alternaria sp. 49 oilseed rape lines were tested, of which a small proportion showed increased resistance to both pathogens. DNA analyses of ten pathogens used for inoculation were also performed. The resistance of seedlings (infection index for the 12 objects) obtained from interspecific hybrids and also control and donor plants of oilseed rape were tested for infection caused by pathogens of the genus Leptosphaeria and Alternaria. Selected genotypes with low infection indices were transferred to resistance breeding

Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars.

Resynthesized (RS) Brassica napus can be used to increase the genetic diversity of this important crop plant and to develop the heterotic gene pool required for successful hybrid breeding programmes. The level of heterosis in F1 hybrids depends on the individual performance of the parents and on the degree of genetic difference between them. However, RS forms obtained from crosses of B. rapa ssp. with B. oleracea ssp. possess many undesirable agronomic traits, such as low quality of seeds, low yield and seed oil content, high erucic acid level in the oil and high glucosinolate content in seed meal. Therefore, RS oilseed rape needs to be improved by crossing with natural double-low oilseed rape, leading to selected double-low quality semi-RS lines that can be used for breeding. In this study, we evaluated the seed yield potential of F1 hybrids derived from crosses between Ogura cytoplasmic male-sterility (CMS) lines and doubled haploid (DH) semi-RS lines with restorer gene in three locations in Poland. The genotype by environment interaction (GE interaction) and general combining ability (GCA) of the restorer and CMS line effects, as well as the effects of heterosis, were also assessed. The results of the study provide the first insights into the use of semi-RS lines as components for the development of new hybrid cultivars. Even the introduction of 50% of the RS oilseed rape genotype to natural restorer lines resulted in a marked heterosis effect, with seed yield ranging from 4.56% to 90.17% more than that of the better parent. The yield of the best hybrid amounted to 108.6% of the seed yield of the open-pollinated cultivar Monolit and 94.4% of that of the hybrid cultivar Arsenal. The best DH semi-RS line S1, which had a significantly positive GCA for seed yield, can be recommended as a possible parent for inclusion in breeding programmes aimed at developing new hybrid cultivars