The use of 1-methylcyclopropene (1-MCP) to extend the shelf life of cherry tomato (Lycopersicon esculentum var. cerasiforme) was investigated. Higher concentrations of 1-MCP delayed the ethylene induced climacteric peaks in mature green (MG) and breaker (BR) fruits. Thirteen days after treatment, control fruits were 55% as firm as fruit treated with 0.11 lL L )1 1-MCP. The initiation of fruit softening, chlorophyll degradation and accumulation of lycopene and carotenoids was delayed in treated fruits. Higher 1-MCP concentrations inhibited the accumulation of lycopene and carotene such that the colour of the fruit did not reach that of control fruit. Treatment of MG cherry tomatoes with 1-MCP enhanced shelf life optimally, while treatment of BR fruits was beneficial where full colour and high content of lycopene and carotenoids is important. Differentiation of the different stages of ripening before application of 1-MCP is needed in order to succeed in accomplishing different postharvest objectives.

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Tomatoes (Lycopersicon esculentum Mill) are one of the biggest vegetable crops in the world, supplying a wide range of vitamins, minerals and fibre in human diets. In the tropics, tomatoes are predominantly grown under sub-optimal conditions by subsistence farmers, with exposure to biotic and abiotic stresses in the open field. Whitefly (Bemisia tabaci Gennadius) is one of the major pests of the tomato, potentially causing up to 100% yield loss. To control whitefly, most growers indiscriminately use synthetic insecticides which negatively impact the environment, humans, and other natural pest management systems, while also increasing cost of production. This study sought to investigate the effectiveness of agronet covers and companion planting with aromatic basil (Ocimum basilicum L.) as an alternative management strategy for whitefly in tomatoes and to evaluate the use of these treatments ontomato growth and yield. Two trials were conducted at the Horticulture Research and Training Field, Egerton University, Njoro, Kenya. Treatments comprised a combination of two factors, (1) growing environment (agronet and no agronet) and (2) companion planting with a row of basil surrounding tomato plants, a row of basil in between adjacent rows of tomato, no companion planting. Agronet covers and companion cropping with a row of basil planted between adjacent tomato rows significantly lowered B. tabaci infestation in tomatoes by 68.7%. Better tomato yields were also recorded in treatments where the two treatments were used in combination. Higher yield (13.75 t/ha) was obtained from tomatoes grown under agronet cover with a basil row planted in between adjacent rows of the tomato crop compared to 5.9 t/ha in the control. Non-marketable yield was also lowered to5.9 t/ha compared to 9.8 t/ha in the control following the use of the two treatments in combination. The results of this study demonstrate the potential viability of using companion cropping and agronet covers in integrated management of B. tabaci and improvement of tomato yield.

Browning is a critical problem, which often limits the shelf life and marketability in fresh-cut lotus tuber. Proteome level changes in response to the browning metabolism were investigated using two-dimensional electrophoresis (2-DE) and MALDI-TOF-TOF. A total of 34 functional protein spots were identified by comparing 2-DE protein patterns of fresh-cut lotus tuber before and after browning. These 34 identified proteins could be classified into 7 functional groups based on the NCBI database, that is, material and energy metabolism (35%), stress response (20%), respiration metabolism (12%), cell structure (12%), signal transduction (6%), gene expression regulation (6%), and unclassified proteins (9%). The group with the greatest difference in protein expression was related to material metabolism and regulation, reactive oxygen species metabolism, and respiratory control. The distinct proteins included universal stress protein (USP), superoxide dismutase (SOD), peroxidase (POD), ferritin, and ATPase.

Two experiments were carried out to investigate the effects of nitrogen application and plant age on edible leaf yield and anti-nutrient content of Solanum nigrum plants. Nitrogen rates were 0, 26, 52, 78 and 104 kg ha-1 , applied in one, two or three applications. Shoots were harvested fortnightly starting at eight weeks up to 20 weeks after transplanting. Edible leaf yield increased with both increasing nitrogen application rates and plant age. Plant age significantly affected the oxalate content. In Experiment 1, oxalate content decreased with plant age between eight weeks and 20 weeks after transplanting. In Experiment 2, the oxalate content increased between eight and 12 weeks after transplanting; but from 16 weeks, it declined with increasing plant age.