Publications by authors named "Kwabena Darkwa"

The productivity of maize, an essential staple food crop in Africa, is severely constrained by the declining fertility of the soil. The combined use of organic and inorganic fertilizers could ameliorate this challenge in a sustainable way to boost maize productivity. Two field trials were conducted at Ashanti -Mampong and Damongo, in the transitional and Guinea Savannah agroecologies of Ghana respectively, to assess the influence of sole and integrated application of chicken manure and NPK fertilizer on the growth and yield of maize.

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Anthracnose disease caused by a fungus is the primary cause of yield loss in water yam (), the widely cultivated species of yam. Resistance to yam anthracnose disease (YAD) is a prime target in breeding initiatives to develop durable-resistant cultivars for sustainable management of the disease in water yam cultivation. This study aimed at tagging quantitative trait loci (QTL) for anthracnose disease resistance in a bi-parental mapping population of Parent genotypes and their recombinant progenies were genotyped using the Genotyping by Sequencing (GBS) platform and phenotyped in two crop cycles for two years.

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Article Synopsis
  • The study focused on using pedigree-based best linear unbiased prediction (P-BLUP) to analyze genetic parameters and breeding values for six important traits in white Guinea yam (Poir.) breeding populations.
  • Results indicated significant nonadditive genetic variances and broad-sense heritability estimates between .45 and .79, suggesting that the selection of superior breeding lines can be effectively done using a multi-trait selection index.
  • The analysis identified 13 clones with high genetic potential for improving traits, achieving positive genetic gains in tuber yield and weight, but negative results for tuber dry matter content and resistance compared to standard varieties.
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Article Synopsis
  • - White Guinea yam is a key tuber crop in West Africa, but its origins are uncertain; this study analyzed 336 accessions to clarify its genetic background.
  • - Unlike previous research suggesting a single origin, this study indicates that white Guinea yam likely arose from hybrids between wild rainforest and savannah species.
  • - The research revealed significant genomic contributions from wild species, particularly in the sex chromosome and around key genes, indicating a complicated domestication process and the potential for using wild species in crop improvement.
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Understanding the diversity and genetic relationships among and within crop germplasm is invaluable for genetic improvement. This study assessed genetic diversity in a panel of 173 D. rotundata accessions using joint analysis for 23 morphological traits and 136,429 SNP markers from the whole-genome resequencing platform.

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A better understanding of the structure and extent of genetic variability in a breeding population of a crop is essential for translating genetic diversity to genetic gain. We assessed the nature and pattern of genetic variability and differentiation in a panel of 100 winged-yam (Dioscorea alata) accessions using 24 phenotypic traits and 6,918 single nucleotide polymorphism (SNP) markers. Multivariate analysis for phenotypic variability indicated that all phenotypic traits assessed were useful in discriminating the yam clones and cultivars.

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