Effect of some pesticides on in-vitro lipid and protein synthesis by the liver of the freshwater teleost, Channa punctatus (Bl.)

In vitro incorporation of (14)C-glucose/acetate into lipids and (14)C-leucine into proteins by the liver of Channa punctatus, exposed to safe application rate (SAR) and sublethal (SL) concentrations of malathion and carbaryl for 30 days (mid-February to mid-March) during the preparatory phase of the reproductive cycle, declined more in the fish exposed to SL concentrations than to SAR concentrations of the pesticides. The decline in incorporation was more marked in the malathion-exposed fish, than in those exposed to was more marked in the malathion-exposed fish, than in those exposed to carbaryl. Hence, malathion is considered more toxic than carbaryl in inhibiting the de-novo synthesis of lipids and proteins by the liver.

Comparison of single seed descent, selective intermating and mass selection for seed size in greengram (Vigna radiata (L.) Wilczek)

Three selection methods (single seed descent (SSD), mass selection and selective intermating) were applied simultaneously to a highly heterogeneous and broadly based population of greengram. Progeny developing after two cycles of selection were evaluated for yield and seven other economic characters. The relative efficacy of each selection method was judged on the basis of the number of high yielding progeny, mean yield of top 10% progeny, and mean of the highest yielding progeny. Selection after two cycles of selective intermating was found to be the best method for generating productive progeny although mass selection favouring smaller seeds was an equally efficient method. Both of these were found superior to SSD selection.

Comparative efficacy of pedigree selection and selective intermating in greengram (Vigna radiata (L.) Wilczek)

Selective intermating and pedigree selection methods were applied simultaneously to highly heterogeneous and heterozygous base populations of greengram in order to compare their relative efficacy in terms of evolving the number of productive lines as well as their production potential. Selection after two cycles of selective intermating was found to be a better method than traditional pedigree selection. The demerits of pedigree selection and merits of selective intermating are discussed. It is suggested that selective intermating replace the widely adopted but less effective pedigree selection for generating promising new material in such autogamous crops as greengram.

Evaluation of acute toxicity of carbaryl and malathion to freshwater teleosts, Channa punctatus (Bloch) and Heteropneustes fossilis (Bloch)

Bioassay tests evaluated the acute toxicity of carbaryl (a carbamate) (50% wettable powder, W.P.), and malathion (50% E.C.) (an organophosphate) (50% emulsifiable concentrate; E.C.) by determining their LC50 and the acute toxic ranges for 24, 48 and 72, and 96-h exposure to Channa punctatus (Bl.) and Heteropneustes fossilis (Bl.). Regression equations and slope functions were determined for different time periods. The relative susceptibility of the fish, the relative toxicity, and the safe concentrations of these biocides were calculated on the basis of LC50 for 96 h. C. punctatus was found to be relatively more susceptible to both the compounds, while malathion was the more toxic of the two biocides.

Phosphate utilization and constitutive synthesis of phosphatases in Thermoactinomyces vulgaris Tsilinsky

Thermoactinomyces vulgaris utilized both organic and inorganic phosphates with equal efficiency for its growth. The specific activities of the thermophilic acid and alkaline phosphatases were found to be maximum at 1 mM concentration of each phosphate source. All the phosphatase isoenzymes (three alkaline and one acidic) were observed irrespective of the substrate source and concentration, suggesting constitutive synthesis of the enzymes. During growth and differentiation, both acid and alkaline phosphatases exhibited uniformly stable patterns of isoenzymes with slight variations in their specific activities.

Mode of inheritance of dwarf stature and allelic relationships among various spontaneous and induced dwarfs of cultivated rice Oryza sativa L

Genetic study of spontaneous and induced dwarfs included the mode of inheritance of dwarf stature and the allelic relationships among various dwarfs. Qualitative genetic analysis involving crosses of fourteen dwarfs with a common tall variety 'IARI 11124' showed that the degree of dominance in the F1 hybrids varied with the cross. With the exception of the crosses of IARI 6579 and IARI 10560 with the tall variety, all crosses exhibited incomplete dominance. The segregation pattern in F2 populations of height classes showed dwarfness to be a monogenic recessive trait functioning, however, in association with modifier complexes of varied strength. From F2 behaviour of all possible crosses involving the fourteen different dwarfs, the allelic relationships were deduced. Three major groups of dwarfs could be recognised. Group I, comprised of FF 36, IARI 5842, IARI 5906-2B, IARI 5923, IARI 10061, IARI 10560 and IARI 11445, was allelic to I-geo-tse and Dee-Gee-Woo-Gen with modifiers of predominantly negative effects, while group-2, comprised of dwarfs IARI 5901-2, IARI 5924, IARI 6579 and IARI 7312B, was also allelic to Dee-Gee-Woo-Gen and I-geo-tse but with large and equal number of modifiers of positive and negative effects. The induced mutant, Central Africa Mutant (CAM) which constituted the third group seemed to possess a dwarfing gene that was non-allelic to those of the above mentioned two groups of dwarfs, with equal strength of modifiers of plus and minus effects. Unlike the dwarfs of spontaneous origin, which are invariably allelic to 'Dee-Gee-Woo-Gen', the induced dwarf was nonallelic. Thus, induced mutagenesis appears to give rise to dwarfing genes different from those found in the naturally occurring dwarfs.