An improved micropropagation system, ex vitro rooting and validation of genetic homogeneity in wild female Momordica dioica: an underutilized nutraceutical vegetable crop
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 × 10−2 mg/L (4.1) and BAP 1.2-IAA 1.2 × 10−2 mg/L (4.4) while on medium supplemented with BAP 1.3-IAA 1.3 × 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.