Evaluation of butterhead lettuce cultivars for winter production under a shadenet structure

Incorrect selection of cultivar leads to profit loss due to variability in yield and in quality characteristics of butterhead lettuce. Nine butterhead lettuce cultivars were evaluated in soil cultivation under a 40% white shadenet structure during the winter season on an experimental farm of the Agricultural Research Council – Vegetable and Ornamental Plant Institute (ARC-VOPI). The experiment was laid out as a randomised complete block design with five replicates. During harvest, 10 plants from each cultivar per replicate were assessed for yield, and five uniform heads were cut longitudinally for internal quality assessment. Quality assessment included compactness, uniformity, tipburn, disease tolerance and bolting tolerance. Results showed that head mass, height, diameter, uniformity, compactness, tipburn, disease tolerance and internal quality were significantly affected by cultivar choice. Recommended cultivars which outperformed the control (Ofelia) based on uniformity, tipburn and percentage marketable harvest were Analena, Fabieto RZ, Lobela and Rousso RZ. Results thus indicate that improved yield and quality of butterhead lettuce cultivars can be obtained by selecting the correct cultivar for winter production.     

Alterations in yield,physicochemical components and mineral composition of onion following organic manure and inorganic nitrogen application

Onion is the one of the most important vegetable crops grown extensively throughout the world; hence, understanding the response of the crop to the form and amount of N provided is of immense importance. In a field experiment, poultry and cattle manure (at 10?t/ha) were compared with four inorganic nitrogen (N) application levels (0, 60, 90 and 120?kg?N/ha), and six combinations of manure and N applications were investigated. Plant growth and total yield (kg/ha) significantly increased, when N application increased from 0 to 120?kg/ha, with or without added poultry manure. Plant height, leaf number and neck thickness were significantly reduced at 0?kg/ha?N plus cattle manure. The bulb ascorbic acid concentration significantly increased with the use of poultry manure (15.94?mg/100?g) and cattle manure (15.94?mg/100?g), compared with 120?kg/ha inorganic N (11.42?mg/100?g). No significant effects were observed on total phenolics and total soluble solids of onion bulbs following the different fertiliser treatments. Cattle manure increased P and K concentrations, whilst poultry manure significantly increased Zn and Fe concentrations in onion bulbs. Onion bulb Ca and Mg concentrations were lower when cattle manure (0.19% and 0.12%) was used than when other organic or inorganic fertilisers were used. Therefore, organic manure increases the concentrations of certain minerals in onions, compared with inorganic N application, without negatively affecting bulb size.