In vitro propagation of Diyarbakır watermelons and comparison of direct seeded and transplanted watermelon

Abstract

A rapid protocol using shoot tip explants for micropropagation of Diyarbakır watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] types Surme, Beyazkış and Karakış was achieved. Shoot tips from 5-day-old in vitro germinated seedlings were cultured on shoot regeneration medium for 3 weeks. Th e eff ects of the diff erent concentrations of benzyl adenine (BA) and carbohydrate types on shoot proliferation were examined. Th e results confi rmed that a range of 0.5-1.0 mg/L of BA was almost equally eff ective in promoting the shoot length of cultures in the 3 genotypes. Sucrose, in the presence of BA, was superior to other carbohydrates for the 3 genotypes studied in terms of the number of proliferated shoots and the average shoot length obtained. Th e highest percentage of rooting was achieved when medium supplemented with 1.0 mg/L of indole-3-butyric acid (IBA) was used for the 3 genotypes. Th e highest frequency of acclimatized plantlets for the 3 genotypes was 85%, 85%, and 90%, respectively, in sterile compost, when the shoots of Beyazkış, Karakış, and Surme were rooted in the IBA-supplemented rooting treatments. Th e Surme genotype produced a signifi cantly higher yield and mean fruit weight than the Beyazkış and Karakış genotypes in both direct-seeded and transplanted watermelons. Th e main soluble sugar of the experimental types was separated, identifi ed, and quantifi ed using high performance liquid chromatography (HPLC). Fructose was found to be the most abundant sugar and was highly detected in Beyazkış for the seeded watermelon and in Karakış for the transplanted watermelon. Th is demonstrates that in vitro propagation can be used to produce high quality diploid Diyarbakır watermelon for use in breeding lines.