Studies on the Extent of Genetic Contamination in Seed Production of Ridge Gourd (Luffa acutangula Roxb.)

Studies were conducted during 2002-2005 (Rabi season) to evaluate the extent of genetic contamination in round fruited ridge gourd (recessive) vehen grown for seed production under open field conditions. The round fruited ridge gourd was sown at 200 m, 400 m, 600 m and 800 m distance from Arlia Sumeet (long fruited) which acted as the local marker (dominant). The highest percentage of genetic contamination was recorded at a distance of 200 m from the contaminator (Arka Sumeet) (28.62% and 88.1%, respectively, in the years 2003 and 2005). It was also observed that there was a gradual reduction in contamination level with increasing distance from 28.62 to 17.44% at 600 m distance in 2003 and 88.11% at 800 m to 74.23% in 2005. The lowest percentage of contamination was recorded at the highest isolation distance (at 600 m, 17.44% in 2003 and at 800 m, 74.24% in 2005), although it is not within the prescribed maximum permissible limit of genetic contamination (1 and 2% for foundation and certified seed respectively). In the present study, in all the isolation distances studied, the level of contamination is well above the permissible minimum seed certification standards (99 and 98 % genetic purity for Foundation and Certified seed respectively). Hence, any reduction in the isolation distance from the prescribed (800 m) isolation would drastically affect the genetic purity of ridge gourd for seed production under open field conditions

Seed Quality Improvement in Okra through Specific Gravity Separation

A study was conducted to assess the efficiency of specific gravity separator in removing partially filled/chaffy seeds of okra during 2007 and 2008. Bulk seed, after extraction, was first subjected to an air screen cleaner with three screens. Then, the good seed fraction obtained was subjected to specific gravity separation. Three fractions were obtained, viz., heavy, medium and light and they were assessed for quality, along with ungraded seed. Test weight, germination percentage, first count, seedling vigour indices I&II and field emergence were significantly higher in the heavy seed fraction than in ungraded seed. Black seed content in heavy seed fraction was significantly low, thereby improving seed quality. Rejection percentage in terms of light and medium seed fractions put together was 3.5% and 12% in 2007 and 2008, respectively. By removal of these fractions, percentage of field emergence improved from 63% to 82% in 2007, and 62.8 to 76.4% in 2008, respectively

Studies on Parental Synchronization in Flowering for Hybrid Seed Production in Onion (Allium cepa L.)

An experiment was conducted at the Indian Institute of Horticultural Research, Bangalore, in Rabi season during 2001-2002 and 2002-2003 to study the flowering of Cytoplasmic Male Sterile Lines CMS (A) and pollinator lines (C) of onion cv. Arka Lalima for working out effective synchrony in hybrid seed production. Results indicated that days to 100% flowering and days to complete flowering in a plant varied significantly in the parental lines and C line was found to be earlier than A line by 12 days and 25 days, respectively. The duration of flowering in a plant was also less in C line (23 days) than in A line (29 days). Due to lack of floral synchrony between parental lines, pollen availability becomes a limiting factor in hybrid seed production in cv. Arka Lalima. Delay in planting of C lines by a week after planting A lines resulted in synchronised flowering of parental lines at peak flowering stage. This also resulted in higher fruit set (80%) and hybrid seed yield (15g/plant) as against planting of A and C lines simultaneously (29.54% and 0.38g, respectively)

Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometer

The observational and operational efficiency of the TIFR 1 meter balloon borne far infrared telescope has been improved by incorporating a multielement solid state optical photometer (SSOP) at the Cassegrain focus of the telescope. The SSOP is based on a 1-D linear photo diode array (PDA). The online and offline processing schemes of the PDA signals which have been developed, lead to improvement in the determination of absolute telescope aspect ($\sim$ 0\farcm8), which is very crucial for carrying out the observations as well as offline analysis. The SSOP and its performance during a recent balloon flight are presented here.Comment: To appear in the February 2000 issue of the PAS

Studies on Physiological and Biochemical Changes in Relation to Seed Viability in Aged Onion Seeds

Rapid loss in viability of onion seeds during seed storage is a major problem. Not much information concerning the physiological and biochemical changes is available. In the present investigations, seeds were aged artificially by exposure to 45°C+75% RH for a period of fifteen days. Samples were collected at three day intervals and physiological and biochemical changes in the aged seeds were compared to those in fresh seeds. Results revealed that ageing affected seed viability and vigour significantly and this effect was more pronounced with increase in duration of exposure to artificial ageing. Marked reduction in germination to an extent of 4,16 and 75% was noticed in three, six and nine day artificially aged (DAA) seeds, respectively, when compared to fresh seeds. Further increase in ageing duration to twelve and fifteen days resulted in total loss of germination. Increase in ageing duration decreased a amylase and dehydrogenase activities but increased peroxidase activity up to nine days of ageing. Lipid peroxidation increased consistently with increase in duration of ageing. At 15 DAA, 26.2% increase in malondialdehyde content over the control was observed. SDS PAGE protein profile and esterase zymograms of aged seeds showed alteration in banding pattern when compared to that of fresh seeds

Effect of extraction methods on physicochemical, nutritional, antinutritional, antioxidant and antimicrobial activity of Moringa (Moringa oleifera Lam.) seed kernel oil

The effect of three different extraction methods, namely supercritical CO2, soxhlet and solvent methods on the yield, efficiency, physico-chemical properties, nutritional, anti-nutritional composition, antimicrobial and antioxidant activities of moringa (Moringa oleifera Lam.) seed kernel oil was investigated in this study. Oil extraction for SC-CO2 were 37.76 g/100g and 98.43%, observed to be higher than those of soxhlet extraction (29.12 g/100g and 76.29%), and significantly lower than solvent extraction (22.12 g/100g and 57.99%). The physico-chemical composition of the oils showed considerable variation among the extraction methods. The SC-CO2 extracted oil was found to be of superior quality, showing negligible thermal degradation and exhibited significantly (p<0.01) higher nutritional and antioxidant activity and lower anti-nutritional composition than the soxhlet and solvent extracted oils. Oils produced by SC-CO2 and soxhlet extraction methods had antimicrobial activities higher than solvent extracted oil. SCCO2 extracted oil was found to have maximum number of bioactive compounds (14 compounds) followed by solvent (8 compounds) and soxhlet (4 compounds) extracted oil. The results of the study demonstrated that SC-CO2 would be a promising process for the extraction of moringa seed kernel oil of premium quality

Experimental Investigation on Mechanical Properties of Hemp/E-Glass Fabric Reinforced Polyester Hybrid Composites

This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites

Measuring nanomechanical motion with an imprecision far below the standard quantum limit

We demonstrate a transducer of nanomechanical motion based on cavity enhanced optical near-fields capable of achieving a shot-noise limited imprecision more than 10 dB below the standard quantum limit (SQL). Residual background due to fundamental thermodynamical frequency fluctuations allows a total imprecision 3 dB below the SQL at room temperature (corresponding to 600 am/Hz^(1/2) in absolute units) and is known to reduce to negligible values for moderate cryogenic temperatures. The transducer operates deeply in the quantum backaction dominated regime, prerequisite for exploring quantum backaction, measurement-induced squeezing and accessing sub-SQL sensitivity using backaction evading techniques

Strong coupling between single-electron tunneling and nano-mechanical motion

Nanoscale resonators that oscillate at high frequencies are useful in many measurement applications. We studied a high-quality mechanical resonator made from a suspended carbon nanotube driven into motion by applying a periodic radio frequency potential using a nearby antenna. Single-electron charge fluctuations created periodic modulations of the mechanical resonance frequency. A quality factor exceeding 10^5 allows the detection of a shift in resonance frequency caused by the addition of a single-electron charge on the nanotube. Additional evidence for the strong coupling of mechanical motion and electron tunneling is provided by an energy transfer to the electrons causing mechanical damping and unusual nonlinear behavior. We also discovered that a direct current through the nanotube spontaneously drives the mechanical resonator, exerting a force that is coherent with the high-frequency resonant mechanical motion.Comment: Main text 12 pages, 4 Figures, Supplement 13 pages, 6 Figure