Seed production and seedling establishment of wild watermelon (Citrullus lanatus var. citroides) in response to various growing media

Erratic seedling emergence and poor stand establishment in most domesticated horticultural crops are affected by, amongst other factors; high temperatures, excess electrical conductivity, poor water holding capacity, and pH. Selection of an appropriate growth medium, which provides suitable environmental conditions for germination and subsequent seedling emergence is critical for a good stand establishment. The objective of this study was to evaluate various growth media for proper seedling establishment and emergence of the wild watermelon Cucumis lanatus var. citroides grown in a shade house. Four different growth media were used, namely; Hutton soil (control), Hygromix, Compost and Culterra seedling mix, which served as treatments. The experiment was set up in a randomized complete block design (RCBD), with three replicates (n = 12). At 14 days after establishing the treatments, emergence percentage (EP %), mean emergence time (MET) (days) and emergence rate index (ERI) (seeds/d) were determined. Treatment had highly significant (P ≤ 0.01) effects on MET (days) and ERI (seeds/d), however, no significant (P ≤ 0.05) effect was observed in EP %. Relative to Hutton soil (EP: 84%), highest EP % was achieved in seeds planted in Hygromix (93.3%), followed by Cultera seedling mix (93.0%) and Compost (92.3%). The earliest seedling emergence (MET: 1.58 days) was obtained in seeds planted in the Culterra seedling mix, whereas the late emergence (MET: 1.80 days) was achieved in seeds planted in Compost growth medium when compared to Hutton soil. Similarly, the fastest seedling emergence was noticed in the Culterra seedling mix with the highest ERI of 26.6 seeds/d, when compared to Compost with a delayed rate of emergence of 21.7 seeds/d. Therefore, the Culterra seedling mix growth medium proved effective in all the parameters tested to be a suitable growth medium for seedling establishment of the wild watermelon, C. lanatus var. citroides seeds in this study.