Sex identification for hop (Humulus lupulus L.), which is a dioecious plant, is very important for breeding process. The use of molecular methods for marker-assisted selection (MAS) provides rapid and reliable identification of sex in F 1 progenies. In the first, we proved the use of specific PCR molecular marker for evaluation of sex in selected plants. This marker was not amplified in 3 from 35 male plants. In the next, we successfully analysed 770 genotypes of F 1 progenies of three crossings. The amplified differences were found in 4 male plants of crossing Sm01 H28, 8 male plants of crossing Sm01 H29 and 5 female plants of crossing Sm00 H20. Statistic analysis confirmed that sex ratios of all F 1 progenies were significantly coincident. Obtained results confirmed that this specific PCR marker successfully identified sex of juvenile hop plants in F 1 progenies and effectively improved breeding process.

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.

The varieties of apples resistant to apple scab (Venturia inaequalis CKE.) are among the latest outcomes of breeding this fruit species not only worldwide but also in the Czech Republic. A common donor of resistance to this disease is Malus floribunda Sieb., clone 821, which has conferred the qualitative resistance based on the dominant Vf gene to a range of varieties. The objective of this article is to characterise Vf gene in a collection of new Czech apple varieties. The published primers were used for PCR evaluation of the collection of twenty Czech varieties, seventeen varieties of world assortment and six new resistant selections of Czech breeding. All varieties possessing resistance based on Vf gene had the heterozygous constitution of Vf gene (Vfvf). Segregated F 1 progeny, which was already selected by infection tests in a greenhouse, was included in the same PCR test. In all progenies recessive homozygous genotypes (vfvf) were also found that were not selected by the infection test. The higher occurrence of recessive homozygous genotypes (vfvf) was detected above all in the progenies of such parental combinations where one of the parents was a donor of quantitative resistance to apple scab.

Potato cyst nematodes (PCN) are the big problem in worldwide planting of potatoes and another Solanaceous plants. Identification of individual pathotypes according to international scheme is very demanding but a very important part of the phytosanitary process to control these pests. Molecular genetic identification of different plant and animal species or individuals is a very interesting way at the present time and let's hope that it will be important in future. This report presents results of the RAPD study of nine different real PCN populations. There were five Globodera rostochiensis populations and four G. pallida populations. Pathotypes Ro2, Ro2/3, Ro4, Ro5, Pa2 and Pa3 were from European populations; population Ro1 and X were of Czech provenance. Genetics variable of these populations was described by a set of six decameric primers (OPA 07, OPG 03, OPG 05, OPG 08, OPG 10 and OPG 13). Genetic dissimilarity was by Gel Manager for Windows evaluated. Detectable differences behind all populations were found and the dendrogram was compiled. The unknown population X was sorted into group of Globodera pallida species subgroup of Pa2 consequently.