Browsing by Author "Mwamahonje, Andekelile"

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    Drought Tolerance and Application of Marker-Assisted Selection in Sorghum
    (MDPI, 2021-11-30) Mwamahonje, Andekelile; Eleblu, John Saviour Yaw; Ofori, Kwadwo
    Sorghum is an important staple food crop in drought prone areas of Sub-Saharan Africa, which is characterized by erratic rainfall with poor distribution. Sorghum is a drought-tolerant crop by nature with reasonable yield compared to other cereal crops, but such abiotic stress adversely affects the productivity. Some sorghum varieties maintain green functional leaves under post-anthesis drought stress referred to as stay-green, which makes it an important crop for food and nutritional security. Notwithstanding, it is difficult to maintain consistency of tolerance over time due to climate change, which is caused by human activities. Drought in sorghum is addressed by several approaches, for instance, breeding drought-tolerant sorghum using conventional and molecular technologies. The challenge with conventional methods is that they depend on phenotyping stay-green, which is complex in sorghum, as it is constituted by multiple genes and environmental effects. Marker assisted selection, which involves the use of DNA molecular markers to map QTL associated with stay-green, has been useful to supplement stay-green improvement in sorghum. It involves QTL mapping associated with the stay-green trait for introgression into the senescent sorghum varieties through marker-assisted backcrossing by comparing with phenotypic field data. Therefore, this review discusses mechanisms of drought tolerance in sorghum focusing on physiological, morphological, and biochemical traits. In addition, the review discusses the application of marker-assisted selection techniques, including marker-assisted backcrossing, QTL mapping, and QTL pyramiding for addressing post-flowering drought in sorghum.
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    Evaluation of Traits’ Performance Contributing to Drought Tolerance in Sorghum
    (MDPI, 2021-08-26) Feyissa, Tileye; Mwamahonje, Andekelile; Eleblu, John Saviour Yaw
    Sorghum (Sorghum bicolor [L.] Moench) is an important food crop for people in semiaridAfrica. The crop is affected by post-flowering drought; therefore, the study was conducted to screentraits contributing to drought tolerance using BC2F4sorghum genotypes in stressed and unstressedwater conditions in a split-plot design. Water stress (0 mm/day) was applied at post-flowering toplant maturity in water-stressed treatment. The genotype SE438 produced the highest grain yield(2.65 ton ha−1) in water-stressed environment and NA316C yielded highest (3.42 ton ha−1) underwell-watered (7 mm/day) environment. There were significant differences of most traits evaluated atp < 0.01 across environments. The mean squares of traits for genotypes by environments revealedinteractions at p < 0.05 and p < 0.01. The indices geometric mean productivity (GMP) and meanproductivity (MP) were highly correlated with yield under well-watered (YP) and water-stressedcondition (YS) and each other. The first principal axis (PC1) explained 59.1% of the total variation.It is the best indicator of yield potential and drought tolerance of sorghum genotypes in this study.Therefore, further improvement is needed to strengthen drought tolerance and yield in sorghum.
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    Evaluation of Traits’ Performance Contributing to Drought Tolerance in Sorghum
    (Agronomy, 2021-08-26) Mwamahonje, Andekelile; Eleblu, John Saviour Yaw; Ofori, Kwadwo
    : Sorghum (Sorghum bicolor [L.] Moench) is an important food crop for people in semi-arid Africa. The crop is affected by post-flowering drought; therefore, the study was conducted to screen traits contributing to drought tolerance using BC2F4 sorghum genotypes in stressed and unstressed water conditions in a split-plot design. Water stress (0 mm/day) was applied at post-flowering to plant maturity in water-stressed treatment. The genotype SE438 produced the highest grain yield (2.65 ton ha−1 ) in water-stressed environment and NA316C yielded highest (3.42 ton ha−1 ) under well-watered (7 mm/day) environment. There were significant differences of most traits evaluated at p < 0.01 across environments. The mean squares of traits for genotypes by environments revealed interactions at p < 0.05 and p < 0.01. The indices geometric mean productivity (GMP) and mean productivity (MP) were highly correlated with yield under well-watered (YP) and water-stressed condition (YS) and each other. The first principal axis (PC1) explained 59.1% of the total variation. It is the best indicator of yield potential and drought tolerance of sorghum genotypes in this study. Therefore, further improvement is needed to strengthen drought tolerance and yield in sorghum.
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    Introgression of QTLs for Drought Tolerance into Farmers’ Preferred Sorghum Varieties
    (MDPI, 2021-09-15) Mwamahonje, Andekelile; Eleblu, John Saviour Yaw; Ofori, Kwadwo
    Sorghum is a major staple food crop for the people in semi-arid areas of Africa and Asia. Post-flowering drought is a global constraint of sorghum production. The study aimed to improve stay-green (STG) characteristics of farmer-preferred sorghum varieties in Tanzania using marker-assisted backcrossing. A total of 752 individuals representing five BC2F1 populations and their parents were genotyped using previously reported KASP markers linked with STG 3A and STG 3B quantitative trait loci (QTL). In the BC2F1 populations, the maximum number of individuals with heterozygous alleles were observed in S35*Pato background (37) whereas only seven individuals derived from the B35*Wahi parents’ background contained heterozygous alleles. Of the 30 single nucleotide polymorphism (SNP) markers, favourable alleles were observed at 18 loci in BC2F1 populations. In the BC2F1 generation, the highest (0.127 kg/panicle) grain yield was observed in the B35*NACO Mtama 1 background population. The genotypic analysis revealed the presence of favourable alleles in homozygous conditions at markers loci associated with STG 3A and STG 3B QTLs in BC2F3 populations, suggesting successful introgression of STG QTLs from the donor parents to the recurrent parents. Across water irrigation regimes, the highest (0.068 kg/panicle) mean grain weight was observed in the genotype NA316C. Therefore, our study demonstrated the utility of marker-assisted backcrossing for drought tolerance improvement of locally adapted sorghum varieties in Africa.
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    Sorghum Production Constraints, Trait Preferences, and Strategies to Combat Drought in Tanzania
    (MDPI, 2021-11-23) Mwamahonje, Andekelile; Eleblu, John Saviour Yaw; Ofori, Kwadwo
    Sorghum is an important food crop for people in drought-prone areas of the world. The production in Tanzania has been ≤1 t ha−1 for a decade. The study was conducted in Iramba, Ikungi, and Kongwa districts to identify factors influencing the sorghum production, adoption rate, and strategies to address drought in Tanzania. The study involved 240 respondents for individual interviews and focus group discussions. Thirty respondents participated in individual interviews while ten farmers participated in the focus group discussion per village. Our study found that birds, poor soil fertility, and drought were the major constraints across the study districts. Drought tolerance, high yield, and early maturity were the most preferred traits by farmers across the study areas. Farmers addressed drought stress in sorghum by practicing early planting early maturing varieties in November and using drought-tolerant varieties. However, most farmers failed to name the diseases and pests affecting sorghum. This study highlights basic information for plant breeders to incorporate traits preferred by farmers in breeding programs when developing new sorghum varieties for sustainable production. The study shows the importance of involving farmers to identify the problems and solutions of sorghum production to increase the adoption rate.