31,458 research outputs found
Genetic evaluation for biometrical traits in fennel (Foeniculum vulgare Mill.)
The genetic variability, heritability, genetic advance, phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) of 13 diverse genotypes of fennel were studied. Considerable amount of variation were recorded for all the characters. The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) in all the characters. The maximum genotypic coefficient of variation (GCV) was recorded for yield plant-1 (40.27) followed by seed yield (32.40 q ha-1), weight of seed umbel-1 (27.12), number of umbellets umbel-1 (17.47) and number of seeds umbel-1 (16.88). High heritability coupled with high genetic advance were recorded for number of seeds umbel-1, yield plant-1, plant height, number of umbel plant-1 and number of branches plant-1.
 
Heritability of some quantitative characters in five varieties of maize (Zea mays l.,) under the influence of various levels of nitrogen
field experiment was conducted at the Kano University of Science and Technology Wudil teaching and research farm during the 2010 and 2011 rainy seasons. Five varieties of maize were studied to estimate components of genetic variance and heritability of some quantitative characters that might exist among them, under the influence of different levels of Nitrogen fertilizer. The experiment was laid out in a randomized complete block design, and replicated three times. The genotype × different levels of nitrogen fertilizer (G × N) influenced the expression of the ear height and yield component. Analysis of variance for plant height revealed highly significant differences among varieties with genotypic coefficient of variation (1.67%) which is smaller than the phenotypic coefficient of variation (1.72%). The estimate of broad-sense heritability was high (0.79), thus showing the presence of considerable amount of genetic variation in total phenotypic variation. While the analysis of variance for ear height showed highly significant differences among genotypic coefficient of variation (0.93%) which is smaller than the phenotypic coefficient of variation (1.05%). The estimate of broad-sense heritability was high (0.49) indicating the presence of considerable amount of genetic variation in total phenotypic variation. The results confirmed thefindings of other researchers on high heritability for plant height. Analysis of variance for grain yield per plot showed greater Genotypic variance than the environmental variance with genotypic coefficient of variation (5.33%) which is smaller than the phenotypic Coefficient of variation (6.24%)and the estimate of broad sense heritability (0.78) was moderately high.Keywords: Heritability, variation, ear height, genes
Quantitative genetics of maize (Zea mays L.) during seedling establishment under cool conditions : a thesis presented in partial fulfillment of the requirements for the degree of Master of Agricultural Science in Plant Science at Massey University
Two experiments were conducted to study cool tolerance in maize (Zea mays L.). The first experiment was carried out under controlled environment to evaluate several genotypes from five synthetic populations which are currently being used to develop hybrid maize for better adaptation to New Zealand climate and to study the qualitative inheritance of maize seedling growth under cool conditions. In this study, diurnal temperature of 16 °C day/6 °C night was used and characters related to seedling growth were examined. The second experiment conducted to study the effect of temperature on maize during its early growth and to examine whether the initial seed constitution and germination characteristics could be used as selection criteria for improvement of the subsequent seedling growth. Eleven physical, chemical, and morphological characters were measured. The growth was studied in germinators under two temperature regimes of 25/20 and 16/6 °C. The genotypic variation was highly significant for all nine characters examined in the first experiment. For the three repeatedly measured characters (i.e. chlorophyll content, shoot and root dry masses), the genotype x time interaction effect was significant. In the second experiment, the variation due to genotypic difference was highly significant only for the initial seed constitution characters and the amount of ion leakage during the early hours of germination process. It was non significant for the time to germinate, seedling growth rates, and seedling growth functions. The variation due to the difference of temperature regimes was significant for the time to germinate and seedling growth but not the growth functions. The genotypes of synthetic line NZS3 showed the best performance for general combining ability (GCA) for almost all characters studied in the first experiment. From all genotypes evaluated, however, only few of them consistently showed good GCA over the characters. Four of the characters studied in the first experiment had moderate to high narrow sense heritabilities, namely total leaves at 50 days after planting (82 %), chlorophyll content (46 %), anthocyanin (69%), and leaf area (62 %). In the second experiment, the estimated broad sense heritabilities observed ranged from very low to very high over all characters. The high broad sense heritabilities were recorded on most of the initial seed constitution characters, the conductivity of ion leakage, and the growth rates of root (length) and shoot (dry mass). Both the phenotypic and genotypic correlation coefficients between pairs are in good agreement and followed the same direction. Amongst the characters examined in the first experiment only time to achieve second mature leaf, total leaf number at 50 day after planting, chlorophyll content, leaf area had considerable correlations to the dry masses. In the second experiment a good correlation with growth rate was observed for the seed weight, nitrogen and maltose contents
Evidence of complex involvement of serotonergic genes with restrictive and binge purge subtypes of anorexia nervosa
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Genetic variability and heritability studies of some reproductive traits in cowpea (Vigna unguiculate (L.) Walp.)
The success of most crop improvement programs largely depends upon the genetic variability and the heritability of desirable traits. The magnitude and type of genetic variability help the breeder to determine the selection criteria and breeding schemes to be used for improvement purposes. A screen house experiment was carried out at Samaru, Nigeria in 1999 and 2000 dry seasons to estimate the genotypic variability of some reproductive traits and their heritability in some selected cowpea varieties. Results of the study showed that there was considerable variation among cultivars for duration of reproductive phase and rate of photosynthate partitioning. Genotypic coefficients of variation were also high for days to first flower, 100-seed weight, plant height, and harvest index. Broad-sense heritability estimate (h2) was 98.9% for 100-seed weight, 94% for duration of reproductive phase, 84.5% for days to first flower, 83.9% for days to maturity, and 77.3% for harvest index. This information showed that there is sufficient genetic variance to warrant selection for improvement in the cowpea genotypes studied. We concluded that considerable progress in cowpea breeding could be achieved by exploiting these traits
Genetic variability of three cassava traits across three locations in Ghana
A study was conducted to assess the extent of genetic variability, broad-sense heritability and correlations for fresh root weight, root number and top weight of five cassava genotypes across three locations in 2 years. Combined analysis of variance revealed highly significant genotypic effect for all the traits. Genotype x environment interaction was also significant for all the traits studied indicating considerable but, varying response of the genotypes to the environments. High broad-sense heritability and genetic advance as percent of the mean were observed for fresh root weight, suggesting that the trait is primarily under genetic control and that a simple recurrent phenotypic selection scheme would be rewarding. Phenotypic coefficients of variation values were larger than their corresponding genotypic coefficient of variation values for all traits. Correlations between the three traits were highly significant and positive indicating that simultaneous progress for the three traits is feasible
Genetic evaluation for biometrical traits in fennel (Foeniculum vulgare Mill.)
The genetic variability, heritability, genetic advance, phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) of 13 diverse genotypes of fennel were studied. Considerable amount of variation were recorded for all the characters. The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) in all the characters. The maximum genotypic coefficient of variation (GCV) was recorded for yield plant-1 (40.27) followed by seed yield (32.40 q ha-1), weight of seed umbel-1 (27.12), number of umbellets umbel-1 (17.47) and number of seeds umbel-1 (16.88). High heritability coupled with high genetic advance were recorded for number of seeds umbel-1, yield plant-1, plant height, number of umbel plant-1 and number of branches plant-1.
 
Development of SSR markers and analysis of diversity in Turkish populations of Brachypodium distachyon
Background: Brachypodium distachyon (Brachypodium) is rapidly emerging as a powerful model system to facilitate research aimed at improving grass crops for grain, forage and energy production. To characterize the natural diversity of Brachypodium and provide a valuable new tool to the growing list of resources available to Brachypodium researchers, we created and characterized a large, diverse collection of inbred lines.
Results: We developed 84 inbred lines from eight locations in Turkey. To enable genotypic characterization of this collection, we created 398 SSR markers from BAC end and EST sequences. An analysis of 187 diploid lines from 56 locations with 43 SSR markers showed considerable genotypic diversity. There was some correlation between SSR genotypes and broad geographic regions, but there was also a high level of genotypic diversity at individual locations. Phenotypic analysis of this new germplasm resource revealed considerable variation in flowering time, seed size, and plant architecture. The inbreeding nature of Brachypodium was confirmed by an extremely high level of homozygosity in wild plants and a lack of cross-pollination under laboratory conditions.
Conclusion: Taken together, the inbreeding nature and genotypic diversity observed at individual locations suggest a significant amount of long-distance seed dispersal. The resources developed in this study are freely available to the research community and will facilitate experimental applications based on natural diversity
Evaluation of durum wheat (Triticum turgidum) genotypes for genetic variability, heritability, genetic advance and correlation studies
The present investigation was undertaken to study the genetic variability, heritability and correlation coefficient analysis for 7 metric traits in 12 durum wheat genotypes at western Oromia during 2015-2018. Significant genotypic differences were observed for the majority traits studied, indicates considerable amount of variation among genotypes for each character. The estimates of genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were high for kernels per spikelet, thousand kernels weight, and number of kernels per spike and grain yield. The remaining traits were ranged from low to moderate estimates. High heritability estimates were recorded for the majority traits studied. The estimated broad – sense heritability (h2) has ranged from 31.6% for maturity to 80.8% for grain yield. High genetic advance combined with high heritability was recorded for plant height, thousand kernel weight, kernels per spike and grain yield, indicates that most likely selection based on phenotype of genotypes could be effective to improve these characters. Grain yield was positively and significantly correlated with spike length, kernels per spike and thousand kernels weight both at genotypic and phenotypic levels. The strong correlation of grain yield with the mentioned traits showed that grain yield could be indirectly improved through improving these traits. This information might be used in the genetics and breeding programmes for improvement of durum wheat
Adaptability of safflower (Carthamus tinctorius L.) genotypes to some New Zealand environments : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Plant Science at Massey University
Seven safflower (Carthamus tinctorius L.) genotypes were grown at three sites (Massey, Aorangi and Flockhouse) in the Manawatu area in years 1978 and 1979. Three additional genotypes from the world germplasm collection were included in the study in 1979. The experimental design was a randomized complete block with three replications. The safflower genotypes were evaluated with respect to several morphological traits, and some important agronomic traits, such as yield, % oil content, % hull content and susceptibility to head rot disease. Data collected on seven safflower genotypes were analysed as a combined experiment with 3 sites and 2 years (Expt. I). The data available on 10 genotypes in 1979 were analysed separately with respect to ten important characters (Expt. II). Of the 23 characters studied in Expt. I, the genotypic variance component (σ2G) was significant only for the following 6 characters:
mid stem leaf length, primary head diameter, involucral bract length and length/width, bract spine index and susceptibility to head rot disease. The addition of 3 genotypes in Expt. II had a marked effect on the magnitude σ2G component. Of the environmental components, site x year interaction effect was the
most significant for the majority of traits. Most of the characters studied in Expt. I showed significant genotype x environment interactions, and in most instances the second order interaction of genotype x site x year being highly significant. Adaptation analyses were performed following procedures of Finlay and Wilkinson (1963). The genotypes Leed and Dart with adaptation coefficients 1.52 and 1.75 respectively were specifically adapted to favourable environments with respect to yield. Cultivar 0-22 and Rio showed general adaptability to the same trait. For % oil content all genotypes except Rio showed general adaptability. Cultivar Rio was slightly specifically adapted to favourable environments. Two forms of broad sense heritabilities (full and restricted) were estimated. In Expt. I, relatively high restricted heritability estimates were obtained for the following traits: leaf length, primary head diameter, bract length and length/width, spine index and susceptibility to head rot disease. The heritability estimates obtained in Expt. II were higher than Expt. I, due to the additional genetic variability in the population. Of the additional traits studied in Expt. II, lodging and susceptibility to leaf spot disease, showed high heritability estimates. Resistances to two fungal diseases - head rot (Botrytis cinerea Pers.) and leaf spot (Stemphylium/Alternaria species) - were assessed in field conditions. The leaf spot disease was detected only in the second year of this study. The cultivars VFSTP-1 and Partial-hull were highly susceptible to head rot disease. The two genotypes from safflower germplasm collection, PI 262437 and PI 306684 had considerable tolerance to leaf spot disease. The optimum plot allocation study indicated that, disregarding costs, an allocation of 2 years, 4 sites and 2 replications would be more efficient than the present allocation. There was no significant correlation between spininess and bird damage. The % oil content and % hull content were negatively correlated at both phenotypic and genotypic levels. Susceptibility to the two diseases were negatively correlated with yield. The susceptibility to head rot disease also showed a significant negative correlation with the % oil content
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