1,720,986 research outputs found
Development of multiple disease resistant common bean (phaseolus vulgaris L.) cultivars using marker assisted selection
No full textPhD-ThesisThe work was undertaken to develop lines with multiple disease resistance incorporating
ALS, BCMNV and CBB and characterization of resistance to ALS from bean landraces to
improve yield of common bean in Tanzania. Single, double and three-way crosses were
made between the susceptible recurrent parent, Kablanketi and resistant parents (Mexico
54, Vax 4 and MCM 5001). The Fa were screened for the presence of resistance markers
through marker assisted selection using SNO2, SAP6 and ROC11 SCAR markers. Thirty
five Fa lines had a combination of genes for ALS, CBB and BCMV while 11 had a
combination of two genes for resistance which forms a good source for folia disease
resistance in breeding programmes. Those lines making 120 plants were validated for the
resistance by phenotyping with three pathogens (ALS, CBB and BCMV) in the screen
house and 31 plants were found resistant to the three pathogens (P. griseola, Xap and
BCMV). The performance of genotypes varied significantly for the disease reactions and
yields. Yield varied from 484 to 3305 kgha'1 with a mean of 2042 kgha'1. The genotypes
with combined resistance and high yields are recommended further for evaluation for
release as a variety. Results also demonstrated that the heritability for disease in this study
was moderate to higher indicating that the selection can be performed in early generation
for some of the pathogens like ALS and BCMV traits. The study confirmed further that
resistance of P. griseola is due to monogenic dominant gene for ALS and single recessive
gene for BCMV. The CBB resistance was found to be conditioned by one major gene
which had effects of partial resistance. The inheritance of ALS resistance in Beti-10,
Nanka, Nanavala and Nkanamna landraces indicated that one single dominant gene
controls the resistance. The heritability for ALS in the landraces was high indicating the
additive genetic effect for that trait. SSR marker Pv-ag004 was found to be linked to
resistance in Beti-10. This landrace can be used in pyramiding the ALS resistant genes iniii
the farmers preferred varieties. However, detailed investigation is needed for the
mechanisms of resistance of the four landraces
Diversity of common bean (Phaseolus vulgaris L.) Genotypes in iron and zinc contents under screenhouse conditions
No full textJournal ArticleDeficiencies in iron and zinc have health consequences for humans, such as anaemia, poor growth and
development in children and low productivity in adults. To guarantee sufficient supply of iron and zinc
through diet mainly consisting of staple foods, such as common bean (Phaseolus vulgaris L.), specific
interventions in plant breeding are needed. However, seed mineral content has not been a selection
criterion for plant breeding, although genetic variation for this trait is present in available germplasm
collections. The aim of this study was to evaluate variability of iron and zinc concentrations among
common bean genotypes grown in four major bean growing areas in Tanzania for breeding work. Ninety
genotypes collected were evaluated under screen house at Sokoine University of Agriculture. A
completely randomized design with three replications was used. Seeds and leaves were collected,
dried, ground and the powder was used for iron and zinc determination using atomic absorption
spectrophotometer. Variation in iron and zinc contents was observed among genotypes both in seeds
and leaves and best genotypes identified. Results have shown a positive and significant
correlation(r=o.416;P<0.001) between iron and zinc, suggesting that genetic factors for increasing iron
and zinc are co-segregating with genetic factors for increasing zinc. Leaves of the studied varieties
have moderate level of zinc (28.0 ppm) and high level of iron (310.0 ppm) forming good source of
micronutrients in combating micronutrient malnutrition. Genotypes with high level of iron and zinc
should be used as a gene source in future breeding work
Diversity of common bean (Phaseolus vulgaris L.) Genotypes in iron and zinc contents under screenhouse conditions
No full textJournal ArticleDeficiencies in iron and zinc have health consequences for humans, such as anaemia, poor growth and
development in children and low productivity in adults. To guarantee sufficient supply of iron and zinc
through diet mainly consisting of staple foods, such as common bean (Phaseolus vulgaris L.), specific
interventions in plant breeding are needed. However, seed mineral content has not been a selection
criterion for plant breeding, although genetic variation for this trait is present in available germplasm
collections. The aim of this study was to evaluate variability of iron and zinc concentrations among
common bean genotypes grown in four major bean growing areas in Tanzania for breeding work. Ninety
genotypes collected were evaluated under screen house at Sokoine University of Agriculture. A
completely randomized design with three replications was used. Seeds and leaves were collected,
dried, ground and the powder was used for iron and zinc determination using atomic absorption
spectrophotometer. Variation in iron and zinc contents was observed among genotypes both in seeds
and leaves and best genotypes identified. Results have shown a positive and significant
correlation(r=o.416;P<0.001) between iron and zinc, suggesting that genetic factors for increasing iron
and zinc are co-segregating with genetic factors for increasing zinc. Leaves of the studied varieties
have moderate level of zinc (28.0 ppm) and high level of iron (310.0 ppm) forming good source of
micronutrients in combating micronutrient malnutrition. Genotypes with high level of iron and zinc
should be used as a gene source in future breeding work
Variability of common bean (Phaseolus vulgaris L.) in Tanzania as evidenced by morphological assessment
No full textResearch articleA total of 84 common bean (Phaseolus vulgaris L.) accessions were collected
from different areas of Tanzania serving as source of germplasm. Nineteen agromorphological
traits of 84 common bean accessions were assessed to analyze
the variability as a core objective for this study. Among all the accessions,
40.48% were characterized by indeterminate bush with moderate climbing ability
and pods distributed evenly up to the plant habitus followed by 36.9%. Similarly,
14.29% were the genotypes with indeterminate bush with semi-climbing main
stem and branches habitus genotypes. Also, 14.29% were the genotypes with
the indeterminate bush with prostrate, and 7.14% were the genotypes with
indeterminate bush with erect branches habitus while 1.19% were the genotypes
with determinate bush least. Phonological, quantitative and qualitative traits
were evaluated and their scores were subjected to principal component analysis
and cluster analysis. The phylogenetic tree demonstrated 2 major clusters
which were further divided into sub-clusters. Principal component analysis
accounted for the accumulative variance of 35.78% revealing morphological
variation highly attributed with variables which had greater than 0.2 Eigen
values. The study demonstrated low morphological variation among the
genotypes and emphasized the need to broaden genetic variability of the
common bean in Tanzania. The results of this study can be used to select the
valuable breeding material for use. Besides, molecular markers can be deployed
to assess further the variability and diversity of these genotypes
Microsatellite analysis of common bean (Phaseolus vulgaris L.) genotypes in Tanzania for diversity in seed iron and zinc micronutrients
No full textJournal articleCommon bean (Phaseolus vulgaris L.) grain has big dietary role in
supplying protein, energy, vitamins, dietary fibre and micronutrients for
millions of people worldwide. In Tanzania, reports have shown existence of
Fe and Zn micronutrient variabilities among the common bean genotypes.
Eighty-four (84) genotypes were collected to study such variability by seed
biochemical and leaf molecular marker analysis. The analyses revealed
significant (p < 0.001) genetic variability for seed Zn and Fe nutrient
contents. Highest seed Fe content was 118 ppm for genotype Kashiransoni
and for seed Zn was 51.81 ppm for Imponzo 5 genotype (both were
collected from NPGRC). With seven (7) SSR primers associated with Fe and
Zn traits, genetic diversity was evaluated. A marker BM154 scored PIC
value 0.967 mean while marker BM160 had a lowest PIC score of 0.899.
Using an estimated genetic similarity value, two main clusters with sub
clusters in the dendrogram were developed. To corroborate the UPGMA
analysis results, a Principal Coordinate Analysis (PCoA) was performed
and displayed outputs into scattered plot presentation. For Fe
micronutrient improvement purposes, Inula was proposed to be crossed
with Kashiransoni while Roba with Imponzo 5 for Zn micronutrient
improvement. Selection was based on both concentrations of nutrients for
each genotype and their genetic similarity distances
Variability of common bean (Phaseolus vulgaris L.) in Tanzania as evidenced by morphological assessment
No full textResearch articleA total of 84 common bean (Phaseolus vulgaris L.) accessions were collected
from different areas of Tanzania serving as source of germplasm. Nineteen agromorphological
traits of 84 common bean accessions were assessed to analyze
the variability as a core objective for this study. Among all the accessions,
40.48% were characterized by indeterminate bush with moderate climbing ability
and pods distributed evenly up to the plant habitus followed by 36.9%. Similarly,
14.29% were the genotypes with indeterminate bush with semi-climbing main
stem and branches habitus genotypes. Also, 14.29% were the genotypes with
the indeterminate bush with prostrate, and 7.14% were the genotypes with
indeterminate bush with erect branches habitus while 1.19% were the genotypes
with determinate bush least. Phonological, quantitative and qualitative traits
were evaluated and their scores were subjected to principal component analysis
and cluster analysis. The phylogenetic tree demonstrated 2 major clusters
which were further divided into sub-clusters. Principal component analysis
accounted for the accumulative variance of 35.78% revealing morphological
variation highly attributed with variables which had greater than 0.2 Eigen
values. The study demonstrated low morphological variation among the
genotypes and emphasized the need to broaden genetic variability of the
common bean in Tanzania. The results of this study can be used to select the
valuable breeding material for use. Besides, molecular markers can be deployed
to assess further the variability and diversity of these genotypes
Microsatellite analysis of common bean (Phaseolus vulgaris L.) genotypes in Tanzania for diversity in seed iron and zinc micronutrients
No full textJournal articleCommon bean (Phaseolus vulgaris L.) grain has big dietary role in
supplying protein, energy, vitamins, dietary fibre and micronutrients for
millions of people worldwide. In Tanzania, reports have shown existence of
Fe and Zn micronutrient variabilities among the common bean genotypes.
Eighty-four (84) genotypes were collected to study such variability by seed
biochemical and leaf molecular marker analysis. The analyses revealed
significant (p < 0.001) genetic variability for seed Zn and Fe nutrient
contents. Highest seed Fe content was 118 ppm for genotype Kashiransoni
and for seed Zn was 51.81 ppm for Imponzo 5 genotype (both were
collected from NPGRC). With seven (7) SSR primers associated with Fe and
Zn traits, genetic diversity was evaluated. A marker BM154 scored PIC
value 0.967 mean while marker BM160 had a lowest PIC score of 0.899.
Using an estimated genetic similarity value, two main clusters with sub
clusters in the dendrogram were developed. To corroborate the UPGMA
analysis results, a Principal Coordinate Analysis (PCoA) was performed
and displayed outputs into scattered plot presentation. For Fe
micronutrient improvement purposes, Inula was proposed to be crossed
with Kashiransoni while Roba with Imponzo 5 for Zn micronutrient
improvement. Selection was based on both concentrations of nutrients for
each genotype and their genetic similarity distances
Effects of soil pH levels on iron and zinc concentrations of common bean (Phaseolus vulgaris L.) genotypes
No full textFull Length Research PaperPlants grown in acid soils experience a variety of stresses which include aluminium, hydrogen and/or
manganese toxicity, as well as nutrient deficiencies of calcium and magnesium. A study was carried out
to determine the influence of soil pH levels on iron and zinc concentrations in leaves and seeds of
twenty-five common bean genotypes. Plastic cups trial was carried out in the screen house to
determine the actual amount of quick lime Ca(OH)2 required to reach a targeted soil pH level. In each
pot, 4 kg soil was amended with Ca(OH)2 to obtain the target soil pH levels of 5.3, 5.5, 6.5 and 7.5. The
experimental design followed a randomized complete block design in a split plot arrangement with
three replications per treatment. The pH levels were treated as main factor and genotypes as sub plot.
Data collected include leaf iron concentration, seed iron concentration, leaf zinc concentration, and
seed zinc concentration and analysis of variance was performed for all data using GenStat statistical
package 15th edition. The result demonstrated that soil pH affects absorption of micronutrients directly
or indirectly by affecting the nutrients availability to common bean plants
The impact of land tenure and degradation on adoption of agroforestry in Uluguru mountains forest, Tanzania
No full textJournal of Environmental Science and Water Resources Vol. 1(10), pp. 236 – 242The influence of land tenure and land degradation on adoption of Agroforestry practices can not be
overstated. A study was carried in Tandai village in Uluguru Mountains of Morogoro Rural District,
Tanzania, to investigate on the impact of land tenure and degradation on the adoption of agroforestry
methods and practices. A total of 50 heads of households, which is approximately 15% of the total
number of farmers in the study area were respondents of the study. Questionnaire and checklist
questions were used to collect primary data from farmers, government and Non-governmental officials
respectively. Results show that although 98% of the respondents owned farmlands, 58% were not
satisfied with their farm sizes. The study also revealed that 92% of the respondents said that the only
way for acquiring extra farmland is through buying while 8% of the respondents said that they can
inherit from their parents and/uncles. Of the respondents, 72% were aware of the causes to land
degradation in their farmlands. From this study it is argued that low rate of adoption of agroforestry in
Uluguru Mountains Forests might be not because of farmers’ resistance to change but due to a
complex and sensitive land tenure systems which is one among other factors underpinning adoption of
the practices. However, farmers’ awareness on intensity and causes of the land degradation on their
farms, and their acknowledgement on the significance of agroforestry methods and practices for land
conservation is a meaningful capital to facilitate adoption of the practices within the complex and
sensitive land tenure system in Uluguru mountains forests
Unexplored agronomic, socioeconomic and policy domains for sustainable cotton production on small landholdings: a systematic review
No full textResearch articleCotton productivity continues to be disputed, despite rapid advancements and
widespread technologies. These uncertainties remain to be critically addressed in
a broad spectrum focusing on domains at the global level. Therefore, this
systematic review provides an overview of the existing advancements in
knowledge, skills, and technologies for sustainable cotton production on small
landholdings. Specifically, the areas of the cotton chain examined are threefold: -
(1) Explore disguised agronomic practices to be endowed for sustainable cotton
production on small landholdings; (2) Explore socioeconomic settings based on
their disparities in contributing to sustainable cotton production on small
landholdings; and (3) Explore existing and feasible institutional policies to be
enforced for sustainable cotton production on small landholdings. This review
shows that worldwide cotton production involves conventional and organic
systems, at the expense of the traditional system. Heavy uses of nitrogenous
fertilizers and pesticides are the common practices in conventional systems, with
some adoptions of precision agriculture practices, and genetically modified
varieties. Rotation and intercropping with early-maturing food crops are also
identified viable options to improve farmers’ attitudes toward adopting cotton-
producing technologies. In socioeconomics, farmers’ livelihoods are improved
by income generation from sales of cotton and labour in the cotton industry.
Gender equity in the cotton industry prioritizes females over males, as females
display a group with a higher level of technology adoption. Generally, clear
institutional policies governing the cotton industry are globally paucity.
Furthermore, efforts to sensitize sustainable cotton production are still highly
questionable and challenged by the superseding climate changes
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