Growth, Yield and Shattering Dynamics of Seeds of Twelve Roselle (Hibiscus sabdariffa L.) Accessions

Roselle (Hibiscus sabdariffa L.) is an important crop grown in tropical and subtropical climates with huge nutritional, economic and industrial benefits. The plant undergoes explosive shattering to disperse seeds after physiological maturity leading to high loss of seeds at the time of harvesting. A field experiment was carried out to determine the effect of different harvesting stages on the growth, yield and shattering dynamics of seeds of twelve Roselle accessions in the Department of Horticulture, Kwame Nkrumah University of Science and Technology, Kumasi from March to November, 2019. A 3x12 factorial design in Randomized Complete Block Design (RCBD) was used for the study, where factor one was harvesting stages at three levels (physiological maturity, one week after physiological maturity and two weeks after physiological maturity) and factor two was accessions at twelve levels. The study revealed that accession HS08 performed best in terms of growth (plant height, the number of leaves, number of branches and stem girth) and reproductive parameters (number of days to flowering) and accessions HS27 and HS08 produced the highest yield (number of pods, number of seeds per pod, and total seed yield). Harvesting of seeds at the physiological maturity stage happened to be the ideal time because seeds were harvested safely without any losses (0%) due to shattering as compared to the other harvesting stages. The study also established a very strong, positive and significant relationship between seed yield and number of leaves (r=0.7093) and the number of branches (r=0.9241). However, there was a strong but negative and significant relationship between seed yield and percentage seed shattering loss (r=-0.9633). There was a very strong, positive and significant relationship between number of leaves and stem girth (r=0.7769). The number of seeds per plant correlated positively with the number of pods (r=0.7358). A regression model which was given by the equation; Y (Seed yield)=670.96-0.3152 (Shattering loss), R2=0.9279, p<0.0000, indicated that shattering loss significantly affected seed yield to an extent that it contributed 93% of the variation in the seed yield.