Superior inbred clones selected in S1 families can integrate an individual reciprocal recurrent selection program in sugarcane by eliminating the genetic load of the population and exploring superior hybrid combinations. Molecular markers can be used for reliable identification of the true selfing-derived clones in these S1 populations.
Brazil is the world leader in papaya production. However, only a small number of cultivars are registered for commercial planting, mainly owing to delays in obtaining cultivars and the high costs of the field phase of breeding programs. These costs can be reduced when molecular tools are combined with conventional breeding methods.
A large herd of Nellore cattle was evaluated using in-depth pedigree analyses. Taking into account the incomplete pedigree due to the use of multiple young sires for mating, the average inbreeding coefficient was calculated as 1.73% for the last generation, which was higher than the regular inbreeding coefficient (0.25%). The effective population size was estimated to be 114, 245, and 101 for the time periods 1995-1999, 1999-2003, and 2003-2007, respectively. Parameters based on the probability of gene origin were used to describe the genetic diversity over time in the herd.
The limited number of papaya varieties available reflects the narrow genetic base of this species. The use of backcrossing as a breeding strategy can promote increases in variability, besides allowing targeted improvements. Procedures that combine the use of molecular markers and backcrossing permit a reduction of the time required for introgression of genes of interest and appropriate recovery of the recurrent genome.
Genetic variation provides a basis upon which populations can be genetically improved. Management of animal genetic resources in order to minimize loss of genetic diversity both within and across breeds has recently received attention at different levels, e.g., breed, national and international levels. A major need for sustainable improvement and conservation programs is accurate estimates of population parameters, such as rate of inbreeding and effective population size. A software system (POPREP) is presented that automatically generates a typeset report.