Application and Use of Presowing Treatment Methods to Improve Germination of Vachellia karroo (Hayne) Banfi & Galasso

A germination experiment of Vachellia karroo seeds was conducted at the Botswana University of Agriculture and Natural Resources, Department of Crop and Soil Sciences laboratory, from September to October 2018. Seeds were collected along the Segoditshane River in Gaborone to investigate the effect of different pre-sowing treatment methods on their germination. The experiment was laid out in a completely randomized design (CRD) with five treatments (control, mechanical scarification, boiling water, hot water and concentrated sulphuric acid (98.8%). Boiling water (30, 60, 180 and 300 seconds) and concentrated sulphuric acid (15, 30, 45 and 60 minutes) had four levels of exposure time. The highest significant (p < 0.01) cumulative germination percentages were recorded in seeds subjected to sulphuric acid for 45 and 60 minutes, mechanical scarification (shortest germination mean time of 2.0-2.3) and boiling water at 30 and 60 seconds (moderate germination mean time of 5-5.9) whereas, the control treatment had the least cumulative germination percentage of 2%. As expected, the same trend was revealed for germination index. The seeds possess seed coat imposed dormancy, which requires sowing treatments. The best treatments for releasing dormancy in V. karroo were sulphuric acid and mechanical scarification and because of the risks associated with the use of sulphuric acid, the researchers recommend mechanical scarification as the suitable treatment method in tree nurseries.Keywords: Seed dormancy, Germination mean time, Germination index, Pre-sowing treatment, Germination percentage, Germination rate, Tree nursery

Nutrient content and biochemical analysis of papaya (Carica papaya L.) hybrids grown in central Kenya

Papaya (Carica papaya L.) is a known powerhouse of nutrients and biochemicals which have health benefits necessary in a human diet. Mineral and vitamin deficiencies, like stunting, wasting and underweight in children, are common in Kenya yet available fruits like papaya can provide those nutrients. This study evaluated the nutritional and biochemical compositions, sugars and the 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activities of 2 newly developed papaya hybrids (JKUAT 7 and JKUAT 8) grown in Kenya and Solo variety, as control; in a completely randomised design which were subjected to one way ANOVA at p?0.05. Results from this study showed significant differences for JKUAT 8 with zinc, iron, potassium and vitamin C contents at 3.28, 3.62, 1145.10 and 448.30 mg/100 g respectively. Solo variety had significantly higher ?-carotene (68.75 mg/100 g), lycopene (25.47 mg/100 g) and flavonoid (0.0178 g/100 g) contents. JKUAT 7 had more phenolic and tannins contents at 0.4434 g/100 g and 81.65 mg/100 g respectively. The DPPH activities ranged from 20 to 80 mg/mL with JKUAT 7 having the highest activity at 20 mg/mL and the least, Solo at 80 mg/mL. JKUAT 7 also exhibited higher total sugar contents in a range of 4.86 to 11.57%: with glucose and fructose at 5.74 and 5.83 % respectively. Our results suggested high nutritional and biochemical profiles of the newly developed JKUAT 7 and JKUAT 8 compared to Solo, the commercial variety. The high nutritional and biochemical contents recorded in the study papayas can be utilised in enhancing human nutrition and health thereby reducing metabolic disorders