No abstract

The experiment was conducted at Agricultural Engineering College & Research Institute, Kumulur, (TNAU), Tamil Nadu with the objectives to test the performance of different cladding (blue and white colour polyethylene) and plastic mulches (silver on black colour) on the growth and yield of cucumber (Cucumis sativus L., Fadia F1, hybrid) to find the suitable cultivation practices for obtaining higher yields in semi-arid regions. The observations of micro climatic parameters such as temperature, relative humidity, solar radiation, light intensity and soil temperature were recorded in each polyhouse and at control (open cultivation). The plant growth parameters like plant height, number of leaves per plant, number of branches, date of first flowering, number of fruits, individual fruit weight and leaf- area were recorded among all the treatments. Among the blue and white polyhouse conditions, favourable solar incidental radiation and light intensity was observed in the white polyhouse as compared to blue polyhouse. Among the plastic mulch and without mulch treatments, the plastic mulch showed negative results under polyhouse cultivation where as positive results on growth and yield parameters at open condition (control).  Significant differences were found among the treatments combinations of white poly house condition without mulch treatment on higher fruit size, fruit weight, number of fruits per plant, number of leaves per plant, leaf area and higher yield might be due to higher photosynthetic active radiation than blue polyhouse. The microclimatic condition recorded in blue polyhouse found to be detrimental to the pathogens under certain wave lengths and resulted in lower incidences of pest and diseases but not supported for higher yield due to low light intensity compared to white polyhouse. White polythene film as cladding material for construction of poly house and without mulching is important to achieve higher growth and yield of Cucumber under semi-arid regions.

Studies were carried out to establish an efficient system for in vitro regeneration of sugarcane cultivar, 2003V46 using chemical mutagens; Ethyl methane sulphonate (EMS) and 2,4dichlorophenoxy acetic acid (2,4D). Young leaf rolls were used as explants for callus induction on MS medium containing different concentrations of EMS(0.6 µM l -1 , 0.8 µM l -1 and 1.0 µM l -1 ) and 2,4D(4mg l -1 , 5mg l -1 and 6 mg l -1 ). Among the different concentrations,2003V46 had taken minimum number of days (10.0) for callus induction with 2, 4D @ 4mg l -1 ,recordingmaximum mean callus size of 2.42 cm with high callus induction frequency (96.89%) and maximum mean number of explants inducing callus (2.86) in addition with superior response in shooting, rooting and hardening characters than EMS.2, 4D at higher concentration (6 mg l -1 ) had inhibitory effect on callusing, shooting and rooting and produced variation for leaf sheath hairiness, shape of bud and internode colour similar to that of the mutagen, EMS.