EFFECT OF SODIUM HYPOCHLORITE ON SEED GERMINATION AND EARLY SEEDLING GROWTH OF SWEET ORANGE (Citrus sinensis (L). OSBECK) AND LIME (Citrus aurantifolia SWINGLE)

This study to investigate the effects of priming duration in 10% bleach (NaOCl) on seed germination and early seedling growth of sweet orange (Citrus sinensis (l) Osbeck) and lime (Citrus aurantifolia Swingle) was conducted in the screen house of the Department of Plant Science and Biotechnology, Rivers State University, Port Harcourt, Rivers State, Nigeria. The experimental design was a Completely Randomised Design (CRD) with 6 replications and 10 treatments as follows: sweet orange seeds primed in 10% bleach for 10mins, 20mins, 30mins; in water for 30mins and unprimed (control) as well as lime seeds primed in 10% bleach for 10mins, 20mins, 30mins; in water for 30mins and unprimed (control). Five seeds each of sweet orange and lime were sown at a depth of 0.5cm in rectangular transparent plastic containers (size = 16 x 10 x 5cm) filled with loamy soil. Data collected were number of days to first and last seedling emergence, percent germination/ emergence, seedling height, number of leaves per seedling. Seedling vigour index (SVI) was calculated. There were significant differences (P = .05) in time to first seedling emergence (10 – 20 days), last seedling emergence days after sowing (29 - 34, DAS), in percentage germination (30 – 90%) and seedling vigour index (8.82) of sweet orange and lime (5.46.). Lime and sweet orange seeds soaked in 10% bleach for 10minutes emerged 10DAS and 20DAS respectively. On average across the treatments, time to last seedling emergence was 34DAS for sweet orange and 29DAS for lime. There were no significant differences in seedling height and number of leaves. Sweet orange and lime soaked in 10% bleach solution for 20mins gave the highest percentage germination and seedling vigour index and is recommended.