Interspecific hybridization in vanilla and molecular characterization of hybrids and selfed progenies using RAPID and AFLP markers

Vanilla, Vanilla planifolia Andrews, is native to Mexico and Central America, but is now cultivated in other parts of the tropics. Continuous clonal propagation has resulted in very little variability for crop improvement programmes in vanilla. In this study, an attempt has been made to increase the spectrum of variation by interspecific hybridization with Vanilla aphylla, an Indian species which is tolerant to Fusarium. Interspecific hybrids were successfully produced and morphological characters and molecular profiles revealed the true hybridity of the progenies. Ten seedling progenies of V planifolia, and four interspecific hybrids obtained from crosses between V planifolia (female) and V aphylla (male) using a number of different loci as markers were evaluated and 319 amplified fragment length polymorphisms (AFLPs) and 83 random amplified polymorphic DNAs (RAPDs) loci were marked. The profiles indicate similarity between the parents, selfed progenies and interspecific hybrids and that all the progenies tested were variable when compared to each other, which can be exploited for crop improvement in vanilla. This is the first report in vanilla, indicating that RAPD and AFLP profiles coupled with morphological characters can be utilized to assess the variability and hybrid nature of genotypes and of successful interspecific hybridization and production of hybrids between V planifolia and V aphylla. (c) 2006 Elsevier B.V. All rights reserved.