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ThesisItem Open Access Genetic variability, path analysis and stability parameters in sesame(Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Sverup, John; KAU; Gopinathan Nair, VBiometric 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.ThesisItem Open Access Evaluation of bhindi hybrids for yield and its components(Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sheela, M N; Manikantan, Nair, PThesisItem Open Access Genetic studies on induced viable mutants in rice [Oryza sativa L.)(Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Vijayagopal, P D; Gopinathan, Nair VThesisItem Open Access Yield and its components in groundnut under partial shade in coconut garden(Department of Plant Breeding, College of Agriculture, Vellayani, 1988) Rajasree, M R; KAU; Gopimony, RA study on the parameters of variability, heritability and genetic advance and correlation of pod yield with other components were undertaken in thirtyone varieties of groundnut to select genotypes having good yield and adaptability under partially shaded conditions of coconut gardens. The study was conducted during kharif 1987 at the Department of Plant Breeding, College of Agriculture, Vellayani, by raising the varieties in a randomised block design with four replications. Analysis of variance revealed significant differences among varieties for the characters like plant height, first date of flowering , flowering duration, pod yield per plant on fresh weight basis, pod number per plant, mature to immature pod ratio, pod yield per plot on fresh and dry weight basis, 100 pod weight, 100 kernel weight, shelling percentage, halum yield per plant and per plot on fresh and dry weight basis, harvest index, photosynthetic efficiency at reproductive phase, leaf area index at reproductive phase and Cercospora leaf spot disease score. Analysis of variance for chlorophyll-a, b and total pigments revealed that there was no significant difference among the varieties with respect to chlorophyll pigment content. Analysis of variance for shade intensity measured in each plot during vegetative and reproductive phase indicated the presence of uniform shade in the experimental field. High genotypic and phenotypic coefficients of variation, heritability and genetic advance were observed for hundred pod weight and mature to immature pod ratio, suggesting the reliability of these characters during the selection programme for the improvement of this crop. Correlation analysis of dry pod yield per plot with twentyfour characters revealed that fresh pod yield per plot, fresh and dry pod yield per plant, pod number per plant, halum yield per plot on fresh and dry weight basis, harvest index and photosynthetic efficiency during reproductive phase showed relatively high genotypic correlation with dry pod yield per plot. The study indicated that for selecting an ideal plant type of groundnut for partially shaded conditions we have to look for the tallest, earliest flowering and vegetatively maximum vigorous individual plant.ThesisItem Open Access Progeny studies of interspecific crosses of abelmoschus(Department of Plant Breeding, College of Agriculture,Vellayani, 1988) Renie Alex, KAU; Nair, N RA study was conducted at the Department of Plant Breeding, College of Agriculture, Vellayani during 1987-’88 aimed at evaluating the F4 generation of interspecific hybrids between two yellow vein mosaic susceptible cultivars of Abelmoschus esculentus and the resistant semi-wild species, A. manihot for yellow vein mosaic resistance and yield. The estimation of genetic parameters of important economic characters, the association among these characters and the path coefficient analysis were undertaken. The F4 progeny lines were evaluated in an RBD with three replications. The genotypes showed significant differences in most of the characters studied. Genotypic coefficient of variation was maximum for number of branches per plant and minimum for first fruiting node. Plant height, days to flowering and fruiting phase showed high heritability and appreciable genetic advance while number of seeds per fruit recorded moderately high heritability and appreciable genetic advance indicating the presence of additive gene action. Number of branches per plant, fruit girth and yellow vein mosaic intensity exhibited high heritability and low genetic advance, while weight of single fruit, fruit length and shoot and fruit borer incidence recorded moderately high heritability and low genetic advance. Correlation studies revealed that number of branches per plant, number of fruits per plant, fruiting phase, number of flowers per plant, weight of single fruit, percentage fruit set, fruit length, fruit girth and number of seeds per fruit exhibited positive correlation to yield and could be considered as the major yield attributing characters. Path coefficient analysis projected number of fruits per plant and plant height as the traits exerting high positive direct effect on yield, while number of branches per plant, number of flowers per plant and fruit length exerted high positive indirect effect on yield through number of fruits per plant. The study indicated that the model for selection of a high yielding variety of bhindi should be based on number of fruits per plant, plant height, number of flowers per plant, fruit length and number of branches per plant. However, scoring for yellow vein mosaic intensity in the F4 progenies revealed that plants resembling the wild parent A.manihot in its short stature, lesser number of branches, increased fruit girth and number of seeds per fruit were resistant to the disease. However, since the fruits of these plants did not conform to the quality standards of cultivated bhindi and had higher percentage of shoot and fruit borer incidence, they were not selected. Plants resistant to the disease and resembling the cultivated bhindi were selected to carry forward to the next generation.ThesisItem Open Access Potential for drought tolerance in cowpea(Department of Plant Breeding, College of Agriculture, Vellayani, 1989) Magie, Mereena; KAU; Sreekumar, S GA research programme was carried out at the department of plant breeding, College of Agriculture, Vellayani, Trivandrum during 1988 with sixteen varieties of cowpea for studying the potential for drought tolerance. The date on twentysix characters and soil moisture percentage in different plots were collected and subjected to analysis of variance/covariance. The genetic variability and correlations were estimated for the characters contributing to drought tolerance, yield and its components. The path analysis was conducted using yield as the effect and seven components contributing to drought tolerance as causes. Analysis of variance for twentysix characters revealed that significant differences existed among varieties for all the characters except for root spread at vegetative period. The analysis of variance for soil moisture percentage showed no significant difference among experimental plots indicating uniform soil moisture status in all the plots. High genotypic coefficient of variation, moderate to high heritability and high genetic advance was shown by characters such as leaf area index at vegetative, flowering and harvest periods, number of pods per plant, hundred grain weight, and proline content. Harvest index also had moderately high heritability and genetic advance. This indicates the reliability of the above components during selection programmes for the improvement of yield. Grain yield per plot showed positive genotypic correlation with leaf area index at vegetative and flowering period, root spread at harvest period, number of pods per plant, root/shoot ratio at vegetative period, grain filling period, and plant height at maturity. Path analysis revealed that harvest index and leaf area index at vegetative period had maximum positive direct effect on yield. Based on the studies on variability, correlation and path analysis it can be concluded that a plant type. Suited to drought conditions should be early flowering with deep and wide spread root system, high root/shoot ratio and leaf area index at vegetative period, low proline content, few number of stomata, long grain filling period and medium duration resulting in the production of more number of pods per plant and high harvest index. The cowpea varieties UPC-124, DPLC-198 and DPLC-216, satisfying the above plant type can be considered as drought tolerant.ThesisItem Open Access Heterosis for yield and resistance to bacterial wilt in brinjal(Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Jameela Thomas; KAU; Gopinathan Nair, VBacterial wilt of brinjal (Solanum malongena L.) caused by Pseudomonas colanacearum E.F Smith is a serious threat to brinjal cultivation all over India. Most of the commercial varieties are highly susceptible to this disease and hence unsuitable for cultivation in wilt endemic areas. Farmers in many places have been forced to abandon cultivation due to heavy incidence of bacterial wilt. Fine cross combinations were made between three resistant varieties (Pusa purple cluster, SM-6 and SMI-10) as ovule parents and each of three commercialbut susceptible varieties (Black beauty, Puma purple long and Puca purple round) as pollen parent , with a view to combine the wilt resistance of the former and high yield potential of the latter. The bacterial pathogen causing wilt in brinjal was isolated. Based on the cultural and physiological characters it was identified as Pseudomonas solanaecearum.ThesisItem Open Access Cross compatibility between Sesamum indicum L. and S. malabaricum(Department of Plant Breeding, College of Agriculture, Vellayani, 1987) Lali, K S; KAU; Gopinathan Nair, VSesame is most valued annual oilseed crop of Kerala. Lack of varietieswith resistance to drought and diseases is the main problem confronting sesame cultivation in the state. The wild species Sesamum malabaricum shows tolerance to drought and most of the diseases. But this wild species appears to be non compatible with the cultivated S. indicum. An investigation was therefore undertaken to study cross compatibility between these two species. Eleven adapted varieties of S. indicum were crossed reciprocally with S. malabaricum. Capsule set was normal in direct as well as reciprocal crosses. In general it was more in reciprocal crosses . In general it was more in reciprocal crosses than in direct crosses. In spite of normal capsule set , these crosses failed to produce any normal seed. The seeds were either medium shrivelled or highly shrivelled. Failure normal seed development in a wide range of crosses confirm that these two species are noncompatible.ThesisItem Open 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, VInvestigations 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.
