Seed germination and morphological characterization of traditional leafy vegetables

Traditional leafy vegetables provide affordable sources of micronutrients to many people in Zimbabwe. They are produced by smallholder farmers with limited knowledge on the agronomic value of high-quality seed and the seed is rarely tested to determine its quality. This study was therefore conducted to evaluate the germination of seeds of three traditional leafy vegetables sourced from five different farmers and the morphological characteristics of the seedlings. The seeds were collected in the growing season of 2015 to 2016, stored at room temperature and tested for germination in the laboratory at regular monthly intervals during storage. Field germination tests were conducted only once. The seeds tested were classified as normal seedlings, abnormal seedlings, fresh non-germinated seeds or dead seeds. Morphological analysis was conducted at seedling stage, including seven qualitative characters and one quantitative character. Mean separation based on the least significance difference at 5% indicated that percentage germination, purity and 1000-seeds weight for all three species significantly differed among sources. The results showed that Cleome gynandra had lowest germination percentages, Amaranthus hybridus was intermediate and Bidens pilosa had highest values throughout the tests. C. gynandra seed exhibited dormancy, showing high levels of fresh non-germinated seed percentage after each test, which is potentially disastrous for the farmers. The combination of pre-chilling, light, potassium nitrate and alternating temperatures as a way of improving germination for C. gynandra needs further validation.