No abstract

Marker assisted selection is the fast and objective method for detection of resistance major genes. This method is practical for identification of some candidate genes of quantitative resistance. Genetic markers based on Polymerase Chain Reaction (PCR) were used for evaluation of F 1 progenies Ornella × Mira and Tábor × Mira. Cultivar Mira has resistance against Ro1 pathotype G. rostochiensis. Cultivars Ornela and Tábor are susceptible to Ro1. Seedlings of F 1 generations were used for analyses. Plants were cultivated in greenhouse. DNA was isolated from tissue discs by GenElute Plant Genomic DNA Kit (Sigma, SRN). PCR marker of major gene H1 was used for bulked analyses, according to (Niewöhner et al. 1995). Size of this marker was 760 bp. Standard infection tests with Ro1 pathotype G. rostochiensis according to Potoček (1987) in all of the analysed genotypes were made. Segregation ratios of F 1 progenies were determined. These ratios have described segregation of resistance markers and segregation of traits in the biological test. The both methods of evaluation of potato's resistance were compared by correlation analyse. High correlations were found between occurrence of PCR marker for H1 and resistance to Ro1 in biological test. Coefficient of correlation r = 0.962 in F 1 progeny Ornella × Mira and r = 0.964 in hybrids Tábor × Mira. Statistical evaluation of real ratios of segregation by infection tests and DNA markers with theoretical ratios of segregation in simplex and duplex H1 gen qualitative determined resistance was made as well. Resistant cultivar Mira as donor of simplex determined resistance was confirmed.

Progressive methods of molecular analyses of DNA are routinely used in the fields of zoological and botanical taxonomy, pest management and plant breeding. Knowledge of species-composition in populations of potato cyst nematodes (Globodera rostochiensis, G. pallida) is very important for selection of appropriate measure of regulation PCN’s occurrence. The molecular method for distinguishing of PCN species is described in this article. European populations of PCN – Šluknov (Ro1), Obersteinbach (Ro2), Harmerz (Ro5), Kalle (Pa2), Chavornay (Pa3), Delmsen (Pa3), and some cysts of unknown pathotype from Kašperské hory (K) locality were used. Species-specific sets of primers for ITS-1 (Internal Transcribed Spacer 1) amplification were designed on base of known sequences ITS-1 of both PCN species by using of freeware Primers! for the World Wide Web. By using of set Fro1-Rro1 was product 411 bp detected (only in cause G. rostochiensis), by using of set Fpa2-Rpa1 the product 239 bp was detected (only G. pallida). For these reasons the identity of the European populations was confirmed. Cysts of population K were identified as G. pallida.

Mitotic polyploidization in vitro was used in selected wild Solanum species and Solanum tuberosum dihaploids. The efficiency of polyploidization by colchicine was compared with that of oryzalin. Oryzalin was more effective than colchicine (P ¼ 0.1). The rate of non-affected to mixoploid to tetraploid regenerants was 22 : 2.5 : 1 (colchicine) and 14 : 2 : 1 (oryzalin). Optimal concentrations and durations were 3.5 mM/24 h for colchicine and 25 or 30 lM for 24 or 48 h for oryzalin (variations in concentration and duration are necessary owing to possible diversity of responses in selected genotypes). Tetraploids were obtained from S. berthaultii, S. bulbocastanum, S. pinnatisectum, S. verrucosum and eleven S. tuberosum dihaploids. The yield of tetraploids derived from tbr dihaploids was lower than that from the wild species (P ¼ 0.01). Tetraploid regenerants were tested in intra-and inter-specific crosses. Three of 43 intra-specific combinations (298 pollinated flowers) were successful and yielded 440 seeds. Inter-specific crosses (138 combinations, 1672 pollinated flowers) yielded 48 seedless berries.Cultivated potato (Solanum tuberosum L., 2n = 4x = 48) is a vegetatively reproduced species with tetrasomic inheritance and high heterozygosity (Tai and Xiong 2005). Unfortunately, the genetic pool of cultivated potato cultivars is limited owing to its narrow germplasm base. Wild Solanum species on the other hand are sources of allelic diversity and have many valuable traits, including biotic and abiotic stress resistance and nutritive quality of tubers (Cardi et al. 1993, Helgeson andHaberlach 1999). Solanum is a model system with a strong mechanism of sexual isolation due especially to ÔeffectiveÕ ploidy (endosperm balance number = EBN; Carputo et al. 1997). Diploid (2n = 2x = 24) wild Solanum species with 1EBN are sexually isolated from wild Solanum species with higher EBN (i.e. diploid/2EBN, tetraploid/2EBN or 4EBN, hexaploid/4EBN) and from tetraploid (2n = 4x = 48, 4EBN) or dihaploid (2n = 2x = 24, 2EBN) Solanum tuberosum.This breeding barrier can be overcome by increasing or decreasing ploidy and EBN prior to crossing (Bamberg et al.

Wild Solanum accessions are a treasured source of resistance against pathogens, including oomycete Phytophthora infestans, causing late blight disease. Here, Solanum pinnatisectum, Solanum tuberosum, and the somatic hybrid between these two lines were analyzed, representing resistant, susceptible, and moderately resistant genotypes, respectively. Proteome and metabolome analyses showed that the infection had the highest impact on leaves of the resistant plant and indicated, among others, an extensive remodeling of the leaf lipidome. The lipidome profiling confirmed an accumulation of glycerolipids, a depletion in the total pool of glycerophospholipids, and showed considerable differences between the lipidome composition of resistant and susceptible genotypes. The analysis of putative resistance markers pinpointed more than 100 molecules that positively correlated with resistance including phenolics and cysteamine, a compound with known antimicrobial activity. Putative resistance protein markers were targeted in an additional 12 genotypes with contrasting resistance to P. infestans. At least 27 proteins showed a negative correlation with the susceptibility including HSP70-2, endochitinase B, WPP domain-containing protein, and cyclase 3. In summary, these findings provide insights into molecular mechanisms of resistance against P. infestans and present novel targets for selective breeding.