Browsing by Author "Muturi, Phyllis"

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    Diversity analysis and genome‑wide association studies of seed weight trait in Bambara groundnut (Vigna subterranea (L.) Verdc.) using diversity array technology sequence derived single nucleotide polymorphism markers
    (UoEm, 2025-02-22) Muturi, Phyllis; Kyallo, Martina; Gasura, Edmore; Yao, Nasser
    Bambara groundnut is an indigenous drought tolerant legume cultivated in Africa. In Kenya, the crop is grown by women and the diver- sity of the accessions grown is unknown. Lack of information on the crop’s diversity and population structure make genetic improvement of the crop dif- fcult. The objectives of this study were to: (i) deter- mine the genetic diversity and population structure of 86 Bambara groundnut accessions from Kenya using 4,399 SNP markers and, (ii) identify SNPs associated with the seed weight of the Bambara groundnut col- lection. The DArT complexity reduction approach in combination with Illumina short-read sequencing (HiSeq 2000) was applied. Population structure anal- ysis suggested three genetic clusters. Accessions from the same county grouped into diferent clusters with exception of accessions from Kilif that distinctly fell into the same cluster. Analysis of molecular vari- ance indicated that 0.16% of the variance was due to genetic diferentiation among the populations, 19% of the variance was as a result of diferentiation among individuals within populations, and 81% variation was within individuals in a population. The study suggested signifcant DArTseq derived SNP mark- ers (p<0.05) distributed across Bambara groundnut contigs 1, 2, 3, and 5 associated with hundred seed weight, though the identifed SNPs were not vali- dated. This study provided an important foundation by ofering valuable insights into the genetic diversity of Bambara groundnut in traditional cultivation areas in Kenya. These fndings can serve as a starting point for further validation and application in Bambara groundnut breeding programs.
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    Nutritional and Phytochemical Composition of Bambara Groundnut (Vigna subterranea [L.] Verdc) Landraces in Kenya
    (UoEM, 2023-06-02) Chelangat, Mercy; Muturi, Phyllis; Gichimu, Bernard; Gitari, Josiah; Mukono, Simon
    Bambara groundnut (Vigna subterranea) is a highly nutritious legume with good drought tolerance attributes and is therefore a suitable candidate for food and nutritional security especially in drought prone areas. This study was conducted to determine the nutritional and phytochemical composition of seventeen Bambara groundnut landraces that were collected from Vihiga, Kakamega, Bungoma, Busia, and Kisumu Counties in Kenya. Prior to characterization, a field experiment was set up in Ishiara Ward in Mbeere North Sub-County in Embu County for two cropping seasons to standardize and multiply the seeds. The experiment was laid out in a Randomized Complete Block Design with three replicates. The harvested seeds were analyzed for their proximate, nutritional, and phytochemical composition using standard procedures. The moisture content ranged from 3.47 to 6.24%, total ash from 3.17 to 4.69%, crude protein from 21.18 to 26.00%, and fats from 4.56 to 7.02%. Iron levels ranged from 4.07 to 5.13 mg/100 g, sodium from 25.14 to 129.66 mg/100 g, potassium from 819.34 to 1,131.80 mg/100 g, and zinc from 0.06 to 0.42 mg/100 g. The tannin levels ranged from 0.01 to 0.04 mg/g, saponins from 0.82 to 1.06 mg/100 g, alkaloids from 0.01 to 0.12 mg/100 g, and flavonoids from 4.07 to 8.45 mg/100 g. The landraces BG-125, BS-148, and BS-145 with relatively higher nutrients composition and those with high levels of phytochemicals such as BS-104 and MU-137 are recommended to plant breeders for further selection and production of certified seeds. These selections will also be promoted to the farmers for production through various extension programs.
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    Rosemary (Rosmarinus officinalis L.) growth rate, oil yield and oil quality under differing soil amendments
    (Heliyon, 2022) Mwithiga, Gikuru; Maina, Samuel; Gitari, Josiah N.; Muturi, Phyllis
    In this work, we examined the influence of different soil amendments namely cow manure alone (Cm), cow manure plus fertilizer (Cm þ F), fertilizer alone (F) and unamended check, control on rosemary growth rate, fat content, oil yield and oil quality. Plant height (PLH), number of primary branches per plant (NOPB) and survival rate were assessed at 0, 90, 180, 270 and 360 days after planting during the 2020–2021 growing season. Rosemary plant essential oil and fat content were extracted using steam distillation and Soxhlet methods, respectively, and determined for quality using the gas chromatography with mass spectrometry (GC-MS) method. Plants grown under Cm had a higher PLH and NOPB, whereas the F treatment largely affected the survival rate of rosemary plants than the control. A total of 26 constituents were identified from the obtained rosemary oil grown under different treatments by use of GC-MS analysis with Cm treatment containing the highest number of oil compounds. The main rosemary oil compounds in the present work were alpha-pinene (29.80%–34.34%), eucalyptol (27.15%–30.26%), verbenone (7.63%–8.14%) and geraniol (4.47%–5.22%). The oil yield from the steam distillation method ranged from 0.45% (v/w) to 0.59% (v/w) while the fat content as measured using the Soxhlet method ranged between 11.22% and 13.36% across various treatments. The essential oil yield and fat content from rosemary grown under Cm, Cm þ F, or F conditions were not significantly different. This study shows that Cm markedly influenced rosemary oil quality when compared to other soil amendments.