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Theses

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1983 - 19886
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Subject: Plant Breeding × End date: 1989 × Start date: 1981 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sesame
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Sverup, John; KAU; Gopinathan Nair, V
    Biometric analysis in a varietal collection of sesame was undertaken to study the genetic variability, correlations, path analysis and stability parameters. One hundred sesame types were evaluated in replicated trials at Vellayani in uplands during rabi and at Kayamkulam in rice fallows during summer. Genetic variability and correlations were estimated and path analysis worked out independently as both the locations. Location trials for estimating stability parameters were conducted at three places viz. in uplands during rabi at Pattambi and Vellayani and in rice fallows during summer at Kayamkulam. Large values for genotypic coefficients of variation were obtained for characters such as number of capsules on branches, number of capsules perplant, number of capsules on main stem and number of branches during rabi as well as summer. The lowest genotypic coefficient of variation was obtained for number of days to maturity during both rabi and summer. High values of heritability were recorded by seed protein content , seed oil content, height upto first capsule and weight of 1000 seeds under both conditions.
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    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sugarcane
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sreekumar, S G; KAU; Gopinathan Nair, V
    Investigations on genetic variability, path analysis and stability parameters wore conducted at the Sugarcane Research Station, Thiruvalla, Sugarcane Research Centre, Chittoor and Horticultural Research Station, Ambalavayal. The analysis of data collected from 48 clones evaluated at Thiruvalla revealed that the clones showed significant differences for all the 21 characters except Juiciness at 10th month in the first ratoon crop. The germination count on the 45th day, shoot count on the 180th day, number of late shoots at harvest, number of millable canes per plot, cane yield per plot and sugar yield per plot recorded moderate to high heritabiiity in the broad sense coupled with high genetic advance both in the plant and in the first ratoon crops indicating that selection based on these characters will be effective in improving cane and sugar yields. Correlation studies revealed that cane yield per plot had significant positive genotypic correlations with germination count on the 43th day, shoot count on the 180th day, number of millable canes per plot, cane weight and length of cane both in the plant and the first ratoon crops. Therefore, improvement in any one or more of these characters will result In a simultaneous improvement in the yiold of cane. Tho quality characters such as Juiciness, brix, pol and C.C.S. percentages at 12th month had positive but non-significant correlations with cane yield In ths plant crop and the first ratoon crop, suggesting difficulty in the simultaneous improvement of cane yield and quality characters through direct selection. The number of late shoots at harvest had highly significant positive genotypic and phenotypic correlations with the yield of cane in the first ratoon crop indicating that the number of late shoots at the time of harvest can be considered as a reliable criterion for the selection of clones with good yielding ability in the ratoon crop. Sugar yield recorded significant positive gonotypic correlations with cane yield and tho components of cane yield such as germination count on the 45th day, number of millable canes per plot, cane weight and length of cane. Sugar yiola also had significant positive genotypic correlations with brix, pol and C.C.S,percentages at 12th month, Tho significant positive gonotypic correlations of sugar yield with cane yield and its important components suggests that by increasing the cane yield, sugar yield per plot can be increased.
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    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sesame
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Sverup John; KAU; Gopinathan Nair, V
    Biometric analysis in a varietal collection of sesame was undertaken to study the genetic variability, correlations, path analysis and stability parameters. One hundred sesame types were evaluated in replicated trials at Vellayani in uplands during rabi and at Kayamkulam in rice fallows during summer. Genetic variability and correlations were estimated and path analysis worked out independently as both the locations. Location trials for estimating stability parameters were conducted at three places viz. in uplands during rabi at Pattambi and Vellayani and in rice fallows during summer at Kayamkulam
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    ThesisItemOpen Access
    Genetic resources utilisation and biometric analysis in groundnut (Arachis hypogaea L.)
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1983) Pushkaran, K; KAU; Gopinathan Nair, V
    Maximising the production, of vegetable oils in the country is one of the badly felt national needs for which the improvement in the productivity of groundnut, the major oilseed crop of the country, deserves the best attention. As a crop, groundnut has wide adaptability and a number of other favourable attributes. Breeding improved varieties suited to the two major areas of groundnut cultivation viz, the traditional uplands during kharif land the non-traditional, but potential rice fallows during summer is an immediate necessity for popularising the crop in this State. Germplasm collection, evaluation and utilisation constitute the basic approaches in the genetic improvement of any crop. Hence this investigation. Eighty eight divergent varieties of groundnut were collected from different sources and subjected to preliminary evaluation in uplands during kharif. Ninety three varieties were evaluated in rice fallows during summer. These varieties showed wide variability in general performance, yield and other attributes within and between the situations. AH-6915 in uplands and TG-3 in rice fallows were the highest yielders. Several varieties were better in yield than the recommended varieties, viz., TMV-2 and TMV-7. A few varieties such as TG-14 end Spanish Improved were consistently superior at both' the situations.
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    ThesisItemOpen Access
    Genetic variability, path analysis and stability parameters in sugarcane
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sreekumar, S G; KAU; Gopinathan, Nair V
    The stability analysis done for component characters on cane yield and sugar yield gave an insight in to the characters contributing to yield stability across environments. Among the cane yield and its most important components viz. number of millable canes per plot and girth of cane the absence of G x E interaction itself is an indication that these characters are stable across environments. The other components of cane yield such as cane weight and length of cane had significant linear components of G x E interaction alone suggesting the stability of these characters. In sugar yield and its more important components viz. brix and pol percentage, the pooled deviations were highly significant suggesting the unpredictability and unstable nature of these quality characters across environments. Therefore, for breeding stable varieties across environments due weightage must be given for characters like number of millable canes per plot, cane weight, girth of cane and cane yield per plot.
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    ThesisItemOpen Access
    Genetic analysis of brown planthopper resistance in rice
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1988) Rema Bai, N; KAU; Gopinathan Nair, V
    The Brown planthopper (BPH), Nilaparvata lugens (Stal), has become a serious threat to rice production throughout Asia. Very extensive losses have occurred in India, Indonesia, and the Phylippines. The most severe outbreak in India occurred in Kerala during 1973-74 in ‘Kole’ lands of Trichur district and ‘Kuttanad’ area of Kottayam and Alleppey districts. Although insecticides provide effective control, this approach is expensive and creates problems of environmental pollution. Resistant varieties can provide protection and insurance against this insect pest at no extra cost and with no danger from chemical residues. Very little work has been done in Kerala to identify sources of resistance to the local biotype of BPH and on the genetic basis of BPH resistance. The major objectives of the present investigation were to identify sources of resistance to BPH and to conduct genetic analysis and understand the mode of inheritance of BPH resistance. One hundred and nine rice types were studied for their reaction to BPH through the bulk seedling test at the seedling stage and tiller test and honeydew experiment at the tillering stage. Out of them 41 were found to be resistant, 22 moderately resistant, 13 moderately susceptible and 33 highly susceptible. In the tiller test, 31 out of the 41 resistant varieties were resistant, nine moderately resistant and one moderately susceptible. The thirty one types found resistant under tiller test were subjected to honeydew experiment, out of which 30 were found to be resistant and one was moderately resistant. 2 The inheritance of resistance was studied in eight types selected from among the 30 types proved to be resistant in all the three tests. They were crossed with the susceptible variety TN1 and the F1, F2 and F3 generations were studied by bulk seedling test, tiller test and honeydew experiment. F1 seedlings were also screened by bulk seedling test, tiller test and honeydew experiment. The F2 progenies were screened by the bulk seedling test and tiller test. The F3 seedlings were screened by bulk seedling test only. The F2 and F3 progenies were scored separately as resistant and susceptible types and the observed segregation ratios were tested against the expected by applying the test of goodness of fit. The F1s of all the eight crosses were resistant indicating that resistance in each of the eight types was governed by dominant gene. The F2 populations of all the eight crosses segregated in the ratio of 3 resistant : 1 susceptible indicating that a single dominant gene governed resistance in each of the eight resistant types. F3 breeding behaviour of the nine F2 resistant plants from each of the eight crosses confirmed the monogenic control of resistance over susceptibility. Two dominant genes Bph1 and Bph3 were identified at IRRI (Bph1 in variety Mudgo and Bph3 in RatuHeenati). In the present study, Mudgo containing Bph1 and RatuHeenati with Bph3 gene were not resistant. Hence it is assumed that the dominant resistant gene identified in the present study is neither Bph1 nor Bph3. 3 Diallele crosses were made between six resistant types selected based on diverse origin. The F1 and F2 progenies of the 15 combinations were studied to get information on the allelie relationship between the resistance genes. The F1 progenies of all the crosses were resistant and the F2 progenies were homogeneous for resistance. This lead to the conclusion that all the six types have the same dominant gene for resistance. All the six resistant types were isogenic and hence all of them are expected to carry a dominant gene for BPH resistance other than Bph1 and Bph3. The present study has thus made available several types resistant to the local biotype of BPH and also enabled the location of a new dominant gene conferring resistance to this biotype. These results and the materials made available can form the basis for a more effective breeding approach for BPH resistance in this region.