• Volume 74, Issue 3

      September 1971,   pages  113-160

    • On better understanding of plant pathogens

      T S Sadasivan

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    • Inheritance of fruit colour in theSolanum nigrum complex

      J Venkateswarlu M Krishna Rao

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      In theSolanum nigrum complex there is wide variability in the fruit colour. In 17 accessions representing diploids, tetraploids and hexaploids, dark shining blue, dull blue, bright red, orange red, yellowish-red and translucent green were observed in the different accessions. Blue is inherited as dominant over red and translucent green; however, the results obtained in crosses between blue and translucent green cannot be explained on the basis of this simple relationship and it is tentatively assumed that duplicate genes are involved in this case. In the tetraploidsS. nigrum, S. villosum andS. miniatum the different shades of red seem to be controlled by alleles at the same locus.

    • Nitrogen requirements of five species ofHelminthosporium

      S M Reddy

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      The growth response ofH. speciferum (Bain.) Nicot,H. rostratum Drechs.,H. hawaiiense Bougn.,H. nodulosum Berk. ex Curt. andH. halodes Drechs. towards fifteen different nitrogen sources was studied. Potassium nitrate, L-asparagine, DL-aspartic acid and L-tyrosine supported good growth, while L-cystine was a poor source for the organisms under study. Sodium nitrite did not permit any growth ofH. rostratum, H. nodulosum andH. halodes, while remaining two species accomplished very poor growth. DL-Tryptophane supported good growth ofH. rostratum, while rest of the species attained poor mycelial growth. DL-Leucine, L-arginine and DL-valine induced good mycelial growth ofH. rostratum, while rest of the species attained moderate mycelial growth.H. hawaiiense grew well on alanine, whileH. nodulosum made meagre growth and remaining three species achieved moderate growth. Ammonium nitrate was a good source forH. rostratum and moderate for remaining species, while ammonium sulphate was good forH. rostratum, moderate forH. hawaiiense and poor for rest of the species.

    • Effectiveness and efficiency of single and combined treatments of radiations and ethyl methane sulphonate inSorghum

      K Sreeramulu

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      The effect of single treatments with X- and gamma rays and EMS and combination treatments of gamma rays sand EMS on survival, seedling growth and seed fertility in M1 and chlorophyll mutation frequency in M2 was studied in the variety Co. 18 ofS. subglabrascens. There was an increase in the reduction of survival and seedling height and seed fertility with an increase in the dose of mutagens. Combined treatments were found to be more effective in reducing the survival and height of seedlings than single treatments, while EMS caused more drastic effect on seed fertility than rest of the mutagens. The frequency of chlorophyll mutations in the M2 increased with dose upto a certain dose level and then levelled off at high doses. EMS induced higher frequency of chlorophyll mutations than treatments with radiations. Combination treatments were found to be the most efficient in inducing the chlorophyll mutations as compared to single treatments. Mutagenic effectiveness was found to be the maximum at high doses of gamma rays and EMS, whereas higher efficiency values were observed at lower concentrations of EMS and middle doses of radiations. EMS was found to be the most effective and efficient mutagen than rest of the mutagens.

    • Chemurgic studies on some diploid and tetraploid grain amaranths

      P S Misra Mohinder Pal C R Mitra T N Khoshoo

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      Analytical data on four important species of grain amaranths show that polyploidy, apart from increasing significantly the grain size and weight without much loss of fertility, has generally maintained the nutritive value found at the diploid level. Lysine content is enhanced in polyploidA. edulis andA. caudatus so also the threonine content in the former.

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