Mycorrhizal Development and Phosphorus Concentration in selected Kenyan Sorghum Cultivars

This study was carried out on sorghum genotypes that exhibited significant difference in growth and production on P-deficient soils. The objective was to find out if the genotypes developed different levels of mycorrhizal associations and tissue phosphorus. Results showed that plants in unfertilized soils developed extensive mycorrhizae than those in fertilized soils, no significant differences was observed in the extent of mycorrhizal development among cultivars grown in P-fertilized soils. The cultivars in unfertilized soils responded differently to mycorrhizal colonization, those with high level of mycorrhizal development increased growth compared to those that had low levels of mycorrhizal development in the unfertilized soils. The cultivars also responded differently to phosphorus concentration in their tissues. Phosphorus fertilizer apparently increased number of leaves and sorghum plant height. There was no relationship between phosphorus concentration in soil and level of mycorrhizal development though fertilizer significantly suppressed the level of mycorrhizal development in the plant

Genetic Diversity in Cultivated Sesame (Sesamum indicum L.)

Genetic diversity of traditional sesame landraces and related wild species in East Africa remains largely unexplored. Knowing what fraction of the available genetic diversity is actually used by the farmers is of central importance for understanding how cultiva- tion shapes the genetic structure of a crop and for the management of biodiversity preservation. Genetic diversity in cultivated sesame and related wild species in East Africa was determined using inter-simple sequence repeats (ISSR). Six reliable ISSR primers generated 51 amplification fragments of which 36 (70.6%) were polymorphic. The number of amplified fragments ranged from 7 to 12 with a mean of 8.5 fragments per primer. The overall gene diversity and Shannon’s index were 0.28 and 0.34, respectively. Jaccard’s similarity coefficient ranged from 0.26 to 0.96, with an average of 0.67. Forty-six accessions of sesame were divided into six clusters, although the clustering did not indicate any clear division among sesame accessions based on their origin. Each wild species was more distant from cultivated sesame than from other wild species, indicating that no cross-pollination with wild species occurred during sesame domestication. These results showed a relatively high genetic diversity in sesame and related wild species. Indian-1 and Indian-2 accessions showed a good amount of genetic divergence. The genetic diversity data uncovered in this study can be exploited to improve traditional landraces of sesame in East Africa

Cell membrane integrity, callose accumulation, and root growth in aluminum-stressed sorghum seedlings

Aluminum stress usually reduces plant root growth due to the accumulation of Al in specific zones of the root apex. The objectives of this study were to determine the localization of Al in the root apex of Sorghum bicolor (L.) Moech. and its effects on membrane integrity, callose accumulation, and root growth in selected cultivars. Seedlings were grown in a nutrient solution containing 0, 27, or 39 μM Al3+ for 24, 48, and 120 h. The Al stress significantly reduced root growth, especially after 48 and 120 h of exposure. A higher Al accumulation, determined by fluorescence microscopy after staining with a Morin dye, occurred in the root extension zone of the sensitive cultivar than in the tolerant cultivar. The membrane damage and callose accumulation were also higher in the sensitive than resistant cultivar. It was concluded that the Al stress significantly reduced root growth through the accumulation of Al in the root extension zone, callose accumulation, and impairment of plasma membrane integrity

Phylogenetic relationship among Kenyan sorghum germplasms based on aluminium tolerance

Eighty nine (89) sorghum lines sourced from various parts of Kenya were used to determine phylogenetic relationships based on 10 DNA fragments at AltSB loci with SbMATE, ORF9 and MITE primers. Nine lines of varying aluminium tolerance levels were selected to compare their SbMATE gene expression via the real-time PCR quantification of SbMATE gene expression. The sorghum line MSCR O2 expressed a thousandfold more SbMATEgene activity than the sensitive lines (MSCRM49, MSCRN84 and MSCRN61) under Al treatment. Analysis was done by agarose gel electrophoresis stained with ethidium bromide. The objective of this study was to assess the level of phylogenetic relationships among the Kenyan sorghum germplasms at a known Al tolerance locus. Hierarchical cluster analysis joined at 70% simple matching coefficient using average linkage similarity level produced nine groups in which 67 lines fell in three major clusters of 39, 15 and 13 lines each. The three Al tolerant lines MSCRO2, MSCRC1 and MSCRN60 were clustered together. Lines MSCRO2, MSCRC1 and MSCRN60, screened to be Al tolerant were genetically related at 70% average linkage similarity level and therefore recommend their further development as a food security measure in Kenya.Keywords: Aluminium (Al) toxicity, Sorghum bicolor, Sorghum bicolor multi-drug, toxic extrusion compound (SbMATE) gene expressionAfrican Journal of Biotechnology Vol. 12(22), pp. 3528-353

An Ethnobotanical Study of the Swamp Wetland Vegetation of Uasin Gishu County, Kenya

Ethnobotanical knowledge associated with wetland plants in Uasin Gishu County, Kenya, was assessed and documented. Data on the uses of plants, their local names, and parts used were collected through semi-structured interviews. Fifty wild plant species distributed across 45 genera and 23 families were cited as having traditional uses in the area. Of these, 26 were used as fodder, 14 as medicine, 12 as firewood, 9 as food, and 11 for construction. Some, like Cyperus papyrus L. and Acacia seyal Delile, had multiple uses. Thirty-one plants (62%) of the total recorded were herbs, 13 (26%) shrubs, 3 (6%) trees, and 3 (6%) climbers. Various plant parts were used for different purposes. Medicinal plants were useful in treating a total of 19 ailments and had various methods of preparation

Mulei et al 2014_An Ethnobotanical Study of wetland vegetation

Ethnobotanical knowledge associated with wetland plants in Uasin Gishu County, Kenya, was assessed and docu- mented. Data on the uses of plants, their local names, and parts used were collected through semi-structured inter- views. Fifty wild plant species distributed across 45 gen- era and 23 families were cited as having traditional uses in the area. Of these, 26 were used as fodder, 14 as medi- cine, 12 as firewood, 9 as food, and 11 for construction. Some, like Cyperus papyrus L. and Acacia seyal Delile, had multiple uses. Thirty-one plants (62%) of the total re- corded were herbs, 13 (26%) shrubs, 3 (6%) trees, and 3 (6%) climbers. Various plant parts were used for different purposes. Medicinal plants were useful in treating a total of 19 ailments and had various methods of preparation

Benson Nyongesa_et al_Genatic Relationship Between Sesame and Related Species_Chromosome and Isozyme.

Sesame is an orphan crop with little research attention in Kenya. Genetic relationship between cultivated sesame and related wild species in Kenya is not well known. The objective of this study was to determine genetic relationship between traditional landraces of sesame and related wild species using somatic chromosome counts and isozyme markers. Somatic chromosome counts of four wild species revealed a consistent chromosome number of 2n = 32, which differed from that of the cultivated sesame (2n = 26), indicating genetic variation in chromosome counts. Only esterase exhibited significant variation and accession-specific esterase bands were identified. Three cathodic and eight anodic bands were observed and the variable bands ranged from 2 to 6 per accession. Cathodic bands with varied relative migration were observed in wild species only, whereas anodic bands were observed for all the accessions. Accessions of cultivated sesame were more genetically diverse compared to wild species. Morogoro, 107UG, Indian-1 and Indian-2 recorded the highest number of esterase bands, while 103w had the lowest number of bands. Few common bands were found between cultivated sesame and related wild species indicating a distant genetic relationship. Few gene markers are available in sesame and related wild species, therefore, esterase isozymes can contribute to studies in the breeding and genetics of sesame

Cheprot et Al_PHYSIOLOGICAL CHARACTERIZATION OF KENYAN SORGHUM LINES.pdf

Eighty nine Kenyan sorghum lines were screened for tolerance to aluminium toxicity in nutrient solution. Relative net root growth; root tip aluminium content and variation in organic acid exudation were used to determine the tolerance or sensitivity of the sorghum lines at 148 μM Al for six days. The lines showed variable reduction in root growth under the Al stress. On the basis of the relative net root growths, three lines were tolerant, nineteen were moderately tolerant and sixty seven were sensitive to the Al stress. The tolerant lines secreted up to five times more citrate compared to sensitive lines under the Al treatment. All the lines secreted extremely low quantities of malate under aluminium stress despite a significant positive regression (R 2 = 0.83) between malate secretion and relative net root growth. There was a negative regression between relative net root growth and root aluminium concentration (R2 = -0.79) among the selected sorghum lines, and the sensitive lines accumulated up to three times the amount of Al compared to the tolerant lines.. The Al tolerant sorghum lines were selected for improved sorghum production in acid soil. The objectives of this study were to (i) identify Al tolerant Kenyan sorghum lines, (ii) investigate tolerance mechanisms employed by Kenyan sorghum lines against Al stress

article1400775075_Too et al_African Journal of Agricultural Research

Sorghum (Sorghum bicolor L. (Moench) is an important food security crop in sub-Saharan Africa. Its production on acid soils is constrained by aluminium (Al) stress, which primarily interferes with root growth. Sorghum cultivation is widespread in Kenya, but there is limited knowledge on response of the Kenyan sorghum cultivars to aluminium stress. The aim of the study was to identify and morphologically characterise aluminium tolerant sorghum accessions. The root growth of three hundred and eighty nine sorghum accessions from local or international sources was assessed under 148 μM Al in soaked paper towels, and 99 of these were selected and further tested in solution. Ten selected accessions were grown out in the field, on un-limed (0 t/ha) or limed (4 t/ha) acid (pH 4.3) soils with high (27%) Al saturation, and their growth and grain yield was assessed. Although the Al stress significantly (P ≤ 0.05) reduced root growth in most of the accessions, there were ten accessions; MCSRP5, MCSR 124, MCSR106, ICSR110, Real60, IS41764, MCSR15, IESV93042-SW, MCSRM45 and MCSRM79f, that retained relatively high root growth and were classified as tolerant. The stress significantly (P ≤ 0.05) reduced seedling root and shoot dry matter in the Al-sensitive accessions. Plant growth and yield on un-limed soil was very poor, and liming increased grain yield by an average 35%. Most of Kenya sorghums were sensitive to Al stress, but a few tolerant accessions were identified that could be used for further breeding for improved grain yield in high aluminium soils

Ojunga(Etiegni)_Impact of a Kraft Pulp and Paper Mill Effl uent on

Phytoplankton and macroinvertebrate assemblages were used to assess the impact of a kraft pulp and paper mill effluent in Kenya, on River Nzoia downstream of the discharge point in relation to changes in water quality during May to June and November 2008 (rainy and dry seasons, respectively). Total phosphorus concentration increased from 0.027 mg·L-1 upstream to 0.04 mg·L-1 downstream. Ammonia nitrogen (NH3-N) concentration was 0.51 mg·L-1 upstream and 0.86 mg·L- 1 downstream. Nitrate concentration stood at 1.18 mg·L-1 upstream compared with the 2.23 mg·L-1 downstream. The pH changed from 4.5 to 5.0 upstream to 5.5 to 6.0 downstream, while DO increased from 6.57 to 7.03 mg·L-1 downstream. The BOD5 (biochemical oxygen demand after five days) values remained almost unchanged from 4.63 mg·L-1 upstream to 4.67 mg·L-1 downstream. Taxon composition of phytoplankton and macroinvertebrates correlated with adverse environmental gradients resulting from the mill’s effluent discharge. Overall, there was a shift in composition and abundance of both phytoplankton and macroinvertebrates, with the downstream site recording high numbers of tolerant taxa (i.e., Microcystis sp. and Chironomus sp.). It was recommended that water quality monitoring with effluents of this nature be done using a combination of chemical analysis and biological indicators such as phytoplankton and macroinvertebrate