GENETIC-RELATIONSHIPS AMONG MELON BREEDING LINES REVEALED BY RAPD MARKERS AND AGRONOMIC TRAITS

RAPD markers and agronomic traits were used to determine the genetic r elationships among 32 breeding, lines of melon belonging to seven vari etal types. Most of the breeding lines were Galia and Piel de Sapo gen otypes, which are currently being used in breeding programmes to devel op new hybrid combinations. A total of 115 polymorphic reliable bands from 43 primers and 24 agronomic traits were scored for genetic distan ce calculations and cluster analysis. A high concordance between RAPDs and agronomic traits was observed when genetic relationships among li nes were assessed. In addition, RAPD data were highly correlated with the pedigree information already known for the lines and revealed the existence of two clusters for each varietal type that comprised the li nes sharing similar agronomic features. These groupings were consisten t with the development of breeding programmes trying to generate two s eparate sets of parental lines for hybrid production. Nevertheless, th e performance of certain hybrids indicated that RAPDs were more suitab le markers than agronomic traits in predicting genetic distance among the breeding lines analysed. The employment of RAPDs as molecular mark ers both in germplasm management and improvement, as well as in the se lection of parental lines for the development of new hybrid combinatio ns, is discussed.