Accessing genetic diversity levels of Brazilian genotypes of castor with AFLP and ISSR markers

Resumo

Castor (Ricinus communis L.), an important oilseed crop for the production of biofuels and high quality lubricants, has a long history of cultivation worldwide. However, very little is known about the genetic diversity of cultivars adapted to the semi-arid conditions of Northeastern Brazil, a strategic area for castor cultivation. Aiming to provide new approaches to select dominant markers for genetic diversity analysis among castor accessions from a Brazilian germplasm bank, we have tested 21 AFLP primer combinations and 16 ISSR primers with 27 genotypes from a Brazilian germplasm bank. PIC, MI and RP values were calculated for both marker systems and a strong correlation was observed among these parameters. Therefore, due to a higher degree of variation, primers could be better selected taking into account the RP values, which ranged from 0.231 to 18.231 (AFLP) and from 1.630 to 9.556 (ISSR). Dissimilarity values ranged from 0.189 to 0.504 in the combined analysis (AFLP + ISSR), with genotypes grouping into four main clusters, although without any evidence of genetic structuration (F_st = 0.108). The successful association between genotypes and speci c marks highlighted the great potential of AFLP and ISSR markers to access the variability within the species. Additionally, by describing new polymorphic markers for genotype differentiation, we provide an important contribution to guide crosses between accessions with traits of interest.