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19902
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Subject: Horticulture × End date: 1991 × Start date: 1990 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Genetics of resistance to aphids (Aphis craccivora Koch) and utility of line mixtures in cowpea (Vigna unguiculata L. Walp)
    (Department of Olericulture, College of Horticulture, Vellanikkara, 1990) Salikutty Joseph; Peter, K V
    Direct damage caused by aphids by sucking plant sap and indirect damage caused by transmitting many viral diseases are serious havocs in cowpea. The constitutes a formidable obstacle in realisation of its yield potential, unless protected with insecticides. This is turn, leads to high cost of production, serious health hazards and atmospheric pollution . In this contest host plant resistance appears to hold great hope for cowpea production. Experiments on "Genetics of resistance to aphids (Aphis craccivora Koch) and utility of line mixtures in cowpea (Vigna unguiculata L. Walp)" were carried out during 1986-1990 at Department of Olericulture, Kerala Agricultural University at Vellanikkara to isolate cowpea line(s) resistant to aphids, to study mechanism of resistance, Inheritance of resistance and to develop physical mixtures to manage aphids. Three resistant and six moderately resistant lines were identified. The resistant lines are Vs 350, Vs 438 and Vs 452. The moderately resistant lines are Vs 350, Vs 438 and Vs 452. The moderately resistant lines are Vs 306, Vs 307, Vs 147, Vs 456, Vs 457 and Vs 458.
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    Evaluation of nutrient uptake in black pepper (Piper nigrum L .)
    (Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 1990) Geetha, C K; KAU; Aravindhakshan, M
    Experiments on the nutritional aspects of black pepper were carried out at the Centre for Advanced Studies on Humid Tropical Tree Crops, College of Horticulture , Vellanikkara and at the Banana Research Station, Kannara, during 1986-1990. The pattern of growth and nutrient- uptake in bush pepper and vine pepper, the relative efficiencies of black pepper varieties in the utilization of applied P and the soil zone of maximum nutrient absorption in pepper vines trailed on dead and live standards were investigated . All the nutrients tried , namely, N, P, K, Ca, Mg and S,had influence on one or more of the growth parameters of bush pepper as well as vine pepper. Application of Ca improved the root characters markedly. Vine pepper had superiority in terms of height, number of leaves and number of roots . Bush pepper produced more number of branches, larger leaves and longer roots. In both the types, the total biomass was a good indicator to applied nutrients . Among the nutrients applied , only N and S increased their concentrations in the stem and leaf of bush pepper and vine pepper. In both the types, treatment devoid of N produced typical N deficiency symptoms. The nature o f response in uptake was more or less similar in all the treatments. The variability in biomass production and nutrient uptake in bush pepper and vine , pepper could be explained by quadratic models for all the nutrients , except Ca. On comparing the quadratic responses In biomass production between the two types of plants, vine pepper revealed an additional response over bush pepper. The differences in nutrient uptake between the two type s of pepper were also highly significant, except for P. Hence, bush pepper cannot be used as a suitable substitute for vine pepper, for purpose o f investigations on nutrient requirements. However, in the context of studies on fertility status and nutrient supplying power of soils , there is scope for using bush pepper as substitute for vine pepper.