PLUM VARIETIES USED AS PARENTS IN ROMANIAN BREEDING PROGRAM

There are about three thousand varieties belonging to Prunus domestica available at present worldwide that can be used as genitors in plum breeding activity. An analysis of the pedigrees of plum cvs. developed in Romanian breeding programs shows that the most are descended from ‘Tuleu gras’, ‘Renclod Althan’, ‘Anna Späth’, ‘Stanley’ and ‘Early Rivers’, called 'ancestors'. That means the majority of plum cvs. have at least one of the ancestors as parent or grandparent. For those 40 plum cvs. registered in Romania in 60 years an increased number of crosses with these 'ancestors' has led to what we call 'inbreeding'. According to data presented in this paper, ‘Tuleu gras’ cv. was the most frequently used parent in the cross combinations, giving origin to 23 cvs. Among the other frequently used genitors were: ‘Renclod Althan’ (7 cvs.), ‘Anna Späth’ (3 cvs.) and ‘Stanley’ (1 cv.). Many of the cultivars – 32 altogether (80%) have originated from hybridization, whereas 4 cvs. have originated from open pollination, others 3 cvs. from mutagenesis and 1 cv. from clonal selection. The goal of this work is to measure genetic diversity presently use in Romanian plum breeding. Pedigrees of each cv. were used to study the genetic contributions of ancestor. Of the 40 cvs. analyzed, 33 had an inbreeding coefficient other than zero. The overall mean inbreeding coefficient was 0.419 for all cvs., where their parentages were known. For cvs. with unknown parentage (nonrelated with known parentage) the inbreeding coefficient is zero. The mean coefficient of coancestry of 40 plum cvs. are 0.081 with ‘Tuleu gras’ cv., 0.019 with ‘Renclod Althan’ and ‘Anna Späth’ cvs., 0.017 with ‘Early Rivers’ cv., 0.014 with ‘d’Agen’ and ‘Renclod Violet’ cvs. and 0.005 with Stanley cv. In conclusion, plum breeders have worked with populations of greatly reduced genetic diversity and this strategy becomes a problem because it leads to genetic impoverishment, and, also, the loss of the genetic resistance to different diseases.

Population genetic analysis of White Park Cattle in Germany

The population of White Park Cattle in Germany is composed of 11 males and 33 females. This group of cattle has been analysed with regards to generation intervals, coancestry, and inbreeding on the basis of three generations of ancestors. The average interval between the current and the parental generation amounts to seven years. The average coefficient of coancestry in the population is estimated to be 18 % and the average degree of inbreeding at 16 %. The rate of inbreeding in the last generation is approximately 12 %. These values exceed those reported for most breeds of production animals.

Analysis of the spatial genetic structure of Passiflora incarnata in recently disturbed sites

In early successional species, short life span and frequent spatial relocation may affect the distribution of genetic variation but the pattern may be altered by reproductive patterns. Passiflora incarnata L. (Passifloraceae), an early successional vine found throughout the southeastern United States, reproduces sexually and asexually through clonal sprouts. We examined the genetic structure of P. incarnata in recently disturbed habitats at three spatial scales: within a patch, among patches separated by 250 m, and between sites separated by 10 km. Genetic variation may be clumped at the scale of neighboring plants if stem resprouting is significant. In each patch, eleven arbitrarily selected plants and their four nearest neighbors were mapped and leaf samples were collected for genetic analysis. The multilocus genotype of each individual for seven polymorphic allozymes was determined. Potential clones were determined by estimating the probability of a second occurrence of each genotype and a multilocus coefficient of coancestry. Data indicated P. incarnata was reproducing primarily sexually. Most of the genetic variation was within a patch with little variation among patches. These data suggest that the genetic structure of this colonizing species was determined by founder effects interacting with long distance pollen movement.Key words: allozymes, passionflower, spatial, genetic structure, early colonizer, Passiflora incarnata.