In vitro plant regeneration from cotyledonary explants of Cucumis melo L. var. cantalupensis and genetic stability evaluation using RAPD analysis

摘要

An efficient plant regeneration protocol useful in genetic studies for important breeding lines of cantaloupe melons was developed. Three cultivars (Charentais-T, Vedrantais and Isabelle) and three doubled-haploid melon lines (NAD, DH-L2 and DH-L6) were tested for their potential to regenerate under in vitro conditions. Cotyledon explants from 6-day-old seedlings were cultured on three Murashige and Skoog based medium supplemented with different combinations of 6-benzylaminopurine (BAP) and indoleacetic acid (IAA). After 5 weeks of culture all the genotypes were able to regenerate on all media, however the regeneration frequency varied widely among the cultivars and the medium combinations used. The Charentais-T cultivar developed the highest number of shoots/explant on media containing BAP 1.0-IAA 1.0 x 10(-2) mg/L (4.1) and BAP 1.2-IAA 1.2 x 10(-2) mg/L (4.4) while on medium supplemented with BAP 1.3-IAA 1.3 x 10(-2) mg/L the Vedrantais genotype gave the best result (2.4). The work first highlighted a good morphogenetic response of the DH lines; among all the genotypes and combination used, NAD (65.6 %) and DH-L6 (85.4 and 50.0 %) had the highest yield of regenerated plants. The results confirmed that the regeneration competence was strongly affected by genotype. Plantlets with well-developed shoot and root systems were successfully acclimatized and exhibited normal morphology and growth characteristics. In order to confirm genetic stability, a PCR-based RAPD analysis was carried out using 20 decamer-primers. No polymorphic bands were observed among all the plants revealing the genetic homogeneity of the regenerants. Furthermore, the ploidy level of regenerated plants was confirmed by flow cytometry.