Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: V. R. K. Reddy x
  • Refine by Access: All Content x
Clear All Modify Search

The role of the different genome combinations in a polyploid on phenotypic stability was analysed in wheat and triticale. Twelve genotypes with four genome combinations (AABB, AABBDD, AABBRR and AABBDDRR) were raised in eight artificially created environments. The data on grains per spike, 100-grain weight and grain yield per plant were recorded and analysed following the models of Perkins and Jinks (1968) and Eberhart and Russell (1966). The results revealed that in polyploid species the genes for stability were not uniformly distributed in different genomes. It was therefore inferred that stability may largely depend on the gene combination rather than on the genome combination.

Restricted access

Attempts were made to produce tetraploid triticales by crossing 6x triticales with diploid rye. In F2, the chromosome number was reduced to between 15 and 23 except in three plants, where the chromosome number was 28, 32 and 38, respectively. An increased frequency of ring bivalents was observed in many F4 plants. In the progeny of the plant with 28 chromosomes, desired plants (four) with 2n = 28 chromosomes were obtained. Data on various agronomic characters were recorded on the progeny of these plants in F5. Reasonably good fertility was noticed in these tetraploid triticale forms.

Restricted access

Abstract  

Thorium along with its daughter products present in the soil is one of the major contributors to the external gamma dose in the environment. To establish the dose levels, quantification of thorium contents in soil samples is very important. As a part of pre-operational environmental radiological surveillance, a total of 23 soil and six sand samples were collected from different locations around the proposed nuclear power plant site of Jaitapur, Maharashtra. Thorium concentrations in these samples were determined by instrumental neutron activation analysis (INAA). Samples were irradiated with neutrons in Apsara reactor at a neutron flux of ~5 × 1011 cm−2 s−1 and radioactive assay was carried out using high resolution gamma ray spectrometry. Relative method of INAA was used for quantification of thorium utilizing 311.9 keV gamma ray of 233Pa, the daughter product of 233Th. The concentrations of thorium in the soil and sand samples were in the ranges of 4.0–18.8 and 1.2–6.2 mg kg−1 respectively.

Restricted access

A field experiment was conducted in Vertisols at Bijapur during 1994-96 to study the effect of tillage practices and integrated nutrient management on winter sorghum yield and soil nutrient availability. The increase in winter sorghum yield with deep tillage over medium and shallow tillage was 27 and 57% in 1994-95 as compared to 18 and 34% in 1995-96. Deep tillage resulted in 22 and 45% higher yield as compared to medium and shallow tillage in the pooled data. This was mainly due to conservation and increased availability of moisture and nutrients, i.e. N, P and K. The higher availability of nutrients in the topsoil (0-0.15 m) as compared to the subsoil (0.15-0.30 m) was due to the application of nutrients in the topsoil layer and the higher rate of mineralization. Among the organic materials applied, Leucaena loppings at 2.5 t ha-1 led to a significantly (9%) higher yield (1636 kg ha-1) over vermicompost (1500 kg ha-1) and was on par with farmyard manure (1572 kg ha-1) in the pooled data and during both years of the study. The higher percentage increase in grain yield with Leucaena application was due to the better moisture conservation and availability of major nutrients, i.e. N, P and K. Winter sorghum responded significantly to N application at 25 kg ha-1 in 1994-95, whereas in 1995-96 and in the pooled data the response varied up to 50 kg N ha-1. In the pooled data, the grain yield increased by 17 and 24% with the application of 25 and 50 kg N ha-1 compared with the control. The higher yields obtained with the application of nitrogen were due to the better availability of nutrients, especially N, as these soils are low in available N.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
R.N. Acharya
,
K. Sudarshan
,
A.G.C. Nair
,
Y.M. Scindia
,
A. Goswami
,
A.V.R. Reddy
, and
S.B. Manohar

Abstract  

The guided thermal neutron beam at 100 MW Dhruva research reactor facility of Bhabha Atomic Research Centre (BARC) was used to carry out prompt gamma-ray neutron activation analysis (PGNAA). The prompt k 0-factors have been determined for the isotopes of the elements H, B, K, Co, Cu, Ca, Ti, Cr, Cd, Ba, Hg and Gd with respect to 1951 keV gamma-line of 36Cl. The prompt k 0-factors for H, Cl and Cu were also measured with respect to the 1381 keV gamma-line of 49Ti. Different samples like NH4Cl, Ti metal, cobalt chloride and other stoichiometric compounds and pure metals were used for this purpose. Prompt gamma-rays were accumulated using a 22% HPGe detector connected to a PC based 8k MCA in single mode counting. The energy calibration in the range of 100–8500 keV was carried out using gamma-rays from 152Eu and 60Co, and the prompt gamma-rays from 36Cl whereas the absolute detection efficiency for this energy range was determined using 152Eu and prompt gamma-rays from 36Cl and 49Ti.

Restricted access