Genetic diversity study of wild Philippine paddy straw mushroom （Volvariella volvacea） was conducted to establish a germplasm collection accessible to volvariella producers in the Philippines. Forty one wild strains...Genetic diversity study of wild Philippine paddy straw mushroom （Volvariella volvacea） was conducted to establish a germplasm collection accessible to volvariella producers in the Philippines. Forty one wild strains were collected from different geographical areas in Northern and Central Luzon region. Strains were differentiated using random amplified polymorphic DNA （RAPD）. A single 10-based primer was used to generate randomly amplified polymorphic DNA （RAPD） in V. volvacea and differences were noted in band size （bp） ranging from 1,800 bp to 550 bp. Principal component analysis （PCA） of the RAPD data revealed 4 groups from wild strains. One strain showed RAPD pattern with band appearance at 1,750, 950 and 750 bp; 3 strains at 1,800 and 750 bp; 8 strains at 1,500 and 550; and the most abundant group with 29 strains at 750 bp. With observed lack of heterogeneity among strains, it is recommended that more collections from the wild should be undertaken for more diverse germplasm collection. Moreover, it is suggested that RAPD can be used to delineate strains of V. volvacea with potential importance on genetic diversity conservation and breeding.展开更多
Jatropha curcas （L） has gained popularity as a biodiesel plant to serve as an alternative fuel source and generate income to small landholders. From the Bioenergy policy of Ghana, the government is collaborating wit...Jatropha curcas （L） has gained popularity as a biodiesel plant to serve as an alternative fuel source and generate income to small landholders. From the Bioenergy policy of Ghana, the government is collaborating with the private sector to develop about one million hectares of Jatropha plantation throughout the country. The objective of this study was to assess the importance which farmers give to ,Jcurcas compared with other indigenous tree species and identify the indigenous uses and niches of J. curcas in Ghana. Three farming communities were selected from each of the ten regions. A total of six hundred farmers, consisting of twenty farmers from each community were selected at random and interviewed with a semi-structured questionnaire. Results revealed that J curcas was identified as one of the most important tree species in nine out of the ten regions. Majority （56%） of the respondents indicated that it is mainly used for medicinal purpose and mostly found around homesteads. However. the study observed that, research attention is needed on integration into agricultural lands, germplasm collection and genetic improvement. These findings will help boost production ofJ. curcas in Ghana for the nation to realize her dream of alternative fuel from the plant.展开更多
The aim of this study was to characterize 103 mango accessions of the field germplasm collection of Embrapa semi-arid region, located in Juazeiro, Bahia, Brazil and to apply 50 morphological descriptors established by...The aim of this study was to characterize 103 mango accessions of the field germplasm collection of Embrapa semi-arid region, located in Juazeiro, Bahia, Brazil and to apply 50 morphological descriptors established by the Brazilian Ministry of Agriculture, livestock and supply to help in the development of new mango cultivars for the Northeastern region of Brazil. Four trees were selected for each accession and eight adult leaves, eight flowers and 16 fruits were collected from each tree. Morphological characteristics ranging from plant size to seed embryo were evaluated. Simple percentages were estimated for all the descriptors. Only the descriptors for leaf symmetry and fruit waxiness did not show variability among the accessions. Eight accessions did not show fruits with fibers, while nine other accessions presented flesh firmness, which is an important characteristic to improve breeding. The soluble solids content was high, above 14 ~Brix for 95% of the accessions with Tommy Atkins showing the lowest value, 12.5 ~Brix. A great diversity was found in the color of the epidermis ranging from green to red. The accessions Amrapali and Salitre presented a dark orange flesh color. The obtained data set, are the most comprehensive so far in Brazil, it allows choosing the best parents to develop new cultivars and will also contribute to the protection of mango cultivars in Brazil.展开更多
The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed....The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed. An evaluation was made of 12 L. corniculatus cultivars introduced from different parts of the world, as well as germplasm naturalized in Chile, being 11 accessions of L. tenuis and 21 accessions ofL. uliginosus collected from 33°S to 38°S and 38°S to 45°S, respectively. Phenological, morphological, and agronomical characters were evaluated. Nitrogen fixation in field conditions and concentrations of condensed tannins in herbage were also included. It is concluded that there are cultivars of high value in L. corniculatus introduced germplasm which can be recommended for different environments of the central zone of Chile, as well as for local species breeding programmes. Information obtained from L. tenuis and L. uliginosus accessions shows genetic variability within both species. L. tenuis germplasm is adapted to clay, medium-textured, or sandy soils with water restrictions and phosphorous deficiency. Therefore, characterized accessions could be used to breed cultivars for low input production systems in constrained environments. L. uliginosus accessions include genotypes collected in sites with acid soils and variable tannin content in plant tissues that may be promissory genetic materials for breeding programmes with the objective of producing cultivars for animal production systems for the wet and acid soils in the southern zone of the country.展开更多
Both governmental and non-governmental organizations are engaged in the promotion of soil and water conservation practices in Northern Ghana, but adoption is believed to be low. This study thus examines the determinan...Both governmental and non-governmental organizations are engaged in the promotion of soil and water conservation practices in Northern Ghana, but adoption is believed to be low. This study thus examines the determinants of conservation practices adoption by farming households in the area. Data for the study were collected from 445 households located in 15 communities in Northern Ghana. Univariate, bivariate and multivariate probit models were used to analyse the decision to adopt six conservation practices in the area. Results show that the major determinants of adoption are plot and cropping characteristics such as location; and socio-economic and institutional variables such as number of contacts with extension officers, membership in farmer association and distance to major market. A policy implication of the study is the strengthening of extension service in the area to significantly boost conservation adootion.展开更多
Adaptive cluster sampling （ACS） has been widely used for data collection of environment and natural resources. However, the randomness of its final sample size often impedes the use of this method. To control the fi...Adaptive cluster sampling （ACS） has been widely used for data collection of environment and natural resources. However, the randomness of its final sample size often impedes the use of this method. To control the final sample sizes, in this study, a k-step ACS based on Horvitz-Thompson （HT） estimator was developed and an unbiased estimator was derived. The k-step ACS-HT was assessed first using a simulated example and then using a real survey for numbers of plants for three species that were characterized by clustered and patchily spatial distributions. The effectiveness of this sampling design method was assessed in comparison with ACS Hansen-Hurwitz （ACS-HH） and ACS- HT estimators, and k-step ACS-HT estimator. The effectiveness of using different k- step sizes was also compared. The results showed that k-step ACS^HT estimator was most effective and ACS-HH was the least. Moreover, stable sample mean and variance estimates could be obtained after a certain number of steps, but depending on plant species, k-step ACS without replacement was slightly more effective than that with replacement. In k-step ACS, the variance estimate of one-step ACS is much larger than other k-step ACS （k 〉 1）, but it is smaller than ACS. This implies that k-step ACS is more effective than traditional ACS, besides, the final sample size can be controlled easily in population with big clusters.展开更多
文摘Genetic diversity study of wild Philippine paddy straw mushroom （Volvariella volvacea） was conducted to establish a germplasm collection accessible to volvariella producers in the Philippines. Forty one wild strains were collected from different geographical areas in Northern and Central Luzon region. Strains were differentiated using random amplified polymorphic DNA （RAPD）. A single 10-based primer was used to generate randomly amplified polymorphic DNA （RAPD） in V. volvacea and differences were noted in band size （bp） ranging from 1,800 bp to 550 bp. Principal component analysis （PCA） of the RAPD data revealed 4 groups from wild strains. One strain showed RAPD pattern with band appearance at 1,750, 950 and 750 bp; 3 strains at 1,800 and 750 bp; 8 strains at 1,500 and 550; and the most abundant group with 29 strains at 750 bp. With observed lack of heterogeneity among strains, it is recommended that more collections from the wild should be undertaken for more diverse germplasm collection. Moreover, it is suggested that RAPD can be used to delineate strains of V. volvacea with potential importance on genetic diversity conservation and breeding.
文摘Jatropha curcas （L） has gained popularity as a biodiesel plant to serve as an alternative fuel source and generate income to small landholders. From the Bioenergy policy of Ghana, the government is collaborating with the private sector to develop about one million hectares of Jatropha plantation throughout the country. The objective of this study was to assess the importance which farmers give to ,Jcurcas compared with other indigenous tree species and identify the indigenous uses and niches of J. curcas in Ghana. Three farming communities were selected from each of the ten regions. A total of six hundred farmers, consisting of twenty farmers from each community were selected at random and interviewed with a semi-structured questionnaire. Results revealed that J curcas was identified as one of the most important tree species in nine out of the ten regions. Majority （56%） of the respondents indicated that it is mainly used for medicinal purpose and mostly found around homesteads. However. the study observed that, research attention is needed on integration into agricultural lands, germplasm collection and genetic improvement. These findings will help boost production ofJ. curcas in Ghana for the nation to realize her dream of alternative fuel from the plant.
文摘The aim of this study was to characterize 103 mango accessions of the field germplasm collection of Embrapa semi-arid region, located in Juazeiro, Bahia, Brazil and to apply 50 morphological descriptors established by the Brazilian Ministry of Agriculture, livestock and supply to help in the development of new mango cultivars for the Northeastern region of Brazil. Four trees were selected for each accession and eight adult leaves, eight flowers and 16 fruits were collected from each tree. Morphological characteristics ranging from plant size to seed embryo were evaluated. Simple percentages were estimated for all the descriptors. Only the descriptors for leaf symmetry and fruit waxiness did not show variability among the accessions. Eight accessions did not show fruits with fibers, while nine other accessions presented flesh firmness, which is an important characteristic to improve breeding. The soluble solids content was high, above 14 ~Brix for 95% of the accessions with Tommy Atkins showing the lowest value, 12.5 ~Brix. A great diversity was found in the color of the epidermis ranging from green to red. The accessions Amrapali and Salitre presented a dark orange flesh color. The obtained data set, are the most comprehensive so far in Brazil, it allows choosing the best parents to develop new cultivars and will also contribute to the protection of mango cultivars in Brazil.
文摘The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed. An evaluation was made of 12 L. corniculatus cultivars introduced from different parts of the world, as well as germplasm naturalized in Chile, being 11 accessions of L. tenuis and 21 accessions ofL. uliginosus collected from 33°S to 38°S and 38°S to 45°S, respectively. Phenological, morphological, and agronomical characters were evaluated. Nitrogen fixation in field conditions and concentrations of condensed tannins in herbage were also included. It is concluded that there are cultivars of high value in L. corniculatus introduced germplasm which can be recommended for different environments of the central zone of Chile, as well as for local species breeding programmes. Information obtained from L. tenuis and L. uliginosus accessions shows genetic variability within both species. L. tenuis germplasm is adapted to clay, medium-textured, or sandy soils with water restrictions and phosphorous deficiency. Therefore, characterized accessions could be used to breed cultivars for low input production systems in constrained environments. L. uliginosus accessions include genotypes collected in sites with acid soils and variable tannin content in plant tissues that may be promissory genetic materials for breeding programmes with the objective of producing cultivars for animal production systems for the wet and acid soils in the southern zone of the country.
文摘Both governmental and non-governmental organizations are engaged in the promotion of soil and water conservation practices in Northern Ghana, but adoption is believed to be low. This study thus examines the determinants of conservation practices adoption by farming households in the area. Data for the study were collected from 445 households located in 15 communities in Northern Ghana. Univariate, bivariate and multivariate probit models were used to analyse the decision to adopt six conservation practices in the area. Results show that the major determinants of adoption are plot and cropping characteristics such as location; and socio-economic and institutional variables such as number of contacts with extension officers, membership in farmer association and distance to major market. A policy implication of the study is the strengthening of extension service in the area to significantly boost conservation adootion.
文摘Adaptive cluster sampling （ACS） has been widely used for data collection of environment and natural resources. However, the randomness of its final sample size often impedes the use of this method. To control the final sample sizes, in this study, a k-step ACS based on Horvitz-Thompson （HT） estimator was developed and an unbiased estimator was derived. The k-step ACS-HT was assessed first using a simulated example and then using a real survey for numbers of plants for three species that were characterized by clustered and patchily spatial distributions. The effectiveness of this sampling design method was assessed in comparison with ACS Hansen-Hurwitz （ACS-HH） and ACS- HT estimators, and k-step ACS-HT estimator. The effectiveness of using different k- step sizes was also compared. The results showed that k-step ACS^HT estimator was most effective and ACS-HH was the least. Moreover, stable sample mean and variance estimates could be obtained after a certain number of steps, but depending on plant species, k-step ACS without replacement was slightly more effective than that with replacement. In k-step ACS, the variance estimate of one-step ACS is much larger than other k-step ACS （k 〉 1）, but it is smaller than ACS. This implies that k-step ACS is more effective than traditional ACS, besides, the final sample size can be controlled easily in population with big clusters.
