A field experiment was conducted during the rabi seasons of 2010 to 2013 to find out the optimum time of sowing and plant spacing for broccoli (var. KTS-1) seed production. Seedlings raised by sowing on four different dates viz. 10 th October, 30 th October, 20 th November and 10 th December were transplanted at two spacing viz. 45 cm x 45 cm and 60 cm x 45 cm. Yield and yield attributing characters were significantly influenced by the treatments. Sowing on 10 th October produced the highest head yield (137.81q/ha) while 10 December sowing produced the lowest head yield (6.75 q/ha) of broccoli. Closer spacing (45 cm x 45 cm) gave significantly higher head yield (88.28 q/ha) than planting at 60 cm x 45 cm distance. The highest seed yield (177 kg/ha) was obtained on planting 10 October sown seedlings at 45 cm x 45 cm distance and was the most remunerative (B: C ratio of 6.44) among all the treatment combinations. Plants from delayed sowing of 20 th November and 10 th December failed to produce viable seeds under agro-climatic condition of Assam.

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SUMMARY The microalga Haematococcus lacustris is a source of astaxanthin used widely in aquaculture, pharmaceutical, and cosmetic industries. A new strain of Haematococcus (LCR‐26C‐1f) isolated from the New Zealand alpine zone was evaluated in this study. The influence of vitamins, micronutrients, various carbon and nitrogen sources were investigated to maximize biomass production in batch cultures using shake flasks. Supplementation of vitamins consisting of thiamine, biotin, and cyanocobalamin improved the cell density by 40% over the vitamin‐free medium. Out of the individual vitamins tested, thiamine was shown to be necessary to maintain high cell densities. The best nitrogen source tested was nitrate in the form of sodium nitrate, at a 40 mM concentration. Heterotrophic growth yielded much lower cell densities compared to autotrophic growth. The micronutrients iron and manganese were essential for growth. However, the best growth was obtained using a micronutrient mix that included iron, copper, cobalt, zinc, manganese and molybdenum.

The present study investigated the effect of different culture conditions on the vegetative growth of a new species, Haematococcus alpinus (strain LCR‐CC‐261f) using airlift photobioreactors. The influence of culture medium, aeration rates, CO2 concentration in air‐gas mixture, temperature, light intensities, and wavelengths were investigated to achieve sustainable high cell density cultures. Growth parameters were determined by fitting the data to a form of the logistic equation that included a lag phase. The shear‐sensitive vegetative cells favored lower aeration rates in the photobioreactors. MLA medium increased to 40 mM nitrate produced high density cultures. Temperatures between 12°C and 18°C, 3% (v/v) CO2 concentration and a narrow photon flux density ranging between 37 and 48 μmol photons · m−2 · s−1 were best suited for growth. The wavelength of the light source also impacted growth and a high cell density of 9.6 × 105 cells · mL−1 was achieved using a mixture of red and blue compared to warm white, red, or blue LEDs.

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