Diallel analysis of provitamin A carotenoid and dry matter content in cassava (&lt;i&gt;Manihot esculenta&lt;/i&gt; Crantz)

Esuma, Williams; Kawuki, Robert; Herselman, L.; Labuschagne, Maryke

doi:10.1270/jsbbs.15159

Cited by 24 publications

(33 citation statements)

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“…Firstly, the low dry matter content, which negatively impacts on processing output and flour quality. The tendency of low dry matter content in cassava roots with high levels of carotenoid content has previously been reported by [36,38]. In Latin America, this negative relationship is non-existent owing to germplasm and evaluations methods employed [39].…”

Section: Discussionmentioning

confidence: 71%

Men and women’s perception of yellow-root cassava among rural farmers in eastern Uganda

et al. 2019

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Background: Global efforts are underway to develop staple crops with improved levels of provitamin A carotenoids to help combat dietary vitamin A deficiency, which has afflicted the health of resource-poor farmers in the developing world. As a staple crop for more than 500 million people in sub-Saharan Africa, cassava enriched with provitamin A carotenoids could have a widespread nutritional impact. Because cassava is the second most important food crop in Uganda, a breeding programme was initiated to develop provitamin A varieties, with some clones already tested in advanced yield selection trials. Methods: A survey was conducted to understand gender-based constraints and opportunities governing farmers' decisions to grow yellow-root cassava in Busia, a rural district in eastern Uganda. Logistic regression was computed to determine predictors of willingness to grow yellow-root cassava. Results: Men, women and youth involved in this study were all aware of a yellow-root cassava landrace popularly grown in eastern Uganda, with at least 85% of each group actively growing the cultivar at the time of this study. Interestingly, both men and women singled out early maturity and high fresh root yield as attributes influencing their preference for the yellow root. An assessment of household participation in cassava production and processing activities showed that women performed the bulk of such activities, with men particularly involved in land preparation and selling of products. Nonetheless, both women and men showed strong indication of acceptance and willingness to cultivate yellow-root cassava, which is an incentive for potential uptake of such varieties in future. However, there was poor knowledge on the nutritional benefits of yellow-root cassava, suggesting need for nutritional education when disseminating improved provitamin A cassava varieties. Conclusions: The study provides strong motivation towards breeding provitamin A cassava varieties that have farmer-preferred traits in the background of disease resistance, an output that could be attained through undertaking participatory variety selection trials.

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Section: Discussionmentioning

confidence: 71%

Men and women’s perception of yellow-root cassava among rural farmers in eastern Uganda

et al. 2019

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“…Multi-trait breeding goals are easier to achieve when favorable genetic relationships, arising from linkage or pleiotropy, exist among target traits (Lynch and Walsh, 1998). In cassava, undesirable phenotypic and genotypic correlations have been reported for some important traits (Njoku et al, 2015;Barandica et al, 2016;Esuma et al, 2016). On the other hand, an additive genetic correlation between any two traits implies a relationship between the breeding values of individuals (Bernardo, 2003).…”

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confidence: 99%

“…On the other hand, an additive genetic correlation between any two traits implies a relationship between the breeding values of individuals (Bernardo, 2003). In cassava, undesirable phenotypic and genotypic correlations have been reported for some important traits (Njoku et al, 2015;Barandica et al, 2016;Esuma et al, 2016). For example, an undesirable negative genetic correlation (r g = −0.45) between DMC and total carotenoid content has been observed in African cassava breeding population .…”

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Genetic Variation and Trait Correlations in an East African Cassava Breeding Population for Genomic Selection

et al. 2019

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Cassava (Manihot esculenta Crantz) is a major source of dietary carbohydrates for >700 million people globally. However, its long breeding cycle has slowed the rate of genetic gain for target traits. This study aimed to asses genetic variation, the level of inbreeding, and trait correlations in genomic selection breeding cycles. We used phenotypic and genotypic data from the National Crops Resources Research Institute (NaCRRI) foundation population (Cycle 0, C0) and the progeny (Cycle 1, C1) derived from crosses of 100 selected C0 clones as progenitors, both to evaluate and optimize genomic selection. The highest broad‐sense heritability (H2 = 0.95) and narrow‐sense heritability (h2 = 0.81) were recorded for cassava mosaic disease severity and the lowest for root weight per plot (H2 = 0.06 and h2 = 0.00). We observed the highest genetic correlation (rg= 0.80) between cassava brown streak disease root incidence measured at seedling and clonal stages of evaluation, suggesting the usefulness of seedling data in predicting clonal performance for cassava brown streak root necrosis. Similarly, high genetic correlations were observed between cassava brown streak disease severity (rg= 0.83) scored at 3 and 6 mo after planting (MAP) and cassava mosaic disease, scored at 3 and 6 MAP (rg= 0.95), indicating that data obtained on these two diseases at 6 MAP would suffice. Population differentiation between C0 and C1 was not well defined, implying that the 100 selected progenitors of C1 captured the diversity in the C0. Overall, genetic gain for most traits were observed from C0 to C1.

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“…These findings suggest that reduced DMC may be a more general phenomenon in provitamin A‐biofortified starch crops. Similar to the transgenic cassava reported here, conventionally bred yellow‐fleshed cassava also showed reduced DMC (Esuma et al ., ,b; Njoku et al ., ). Ceballos et al .…”

Section: Discussionmentioning

confidence: 99%

Provitamin A biofortification of cassava enhances shelf life but reduces dry matter content of storage roots due to altered carbon partitioning into starch

Beyene

Solomon

Chauhan

et al. 2017

Plant Biotechnology Journal

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SummaryStorage roots of cassava (Manihot esculenta Crantz), a major subsistence crop of sub‐Saharan Africa, are calorie rich but deficient in essential micronutrients, including provitamin A β‐carotene. In this study, β‐carotene concentrations in cassava storage roots were enhanced by co‐expression of transgenes for deoxy‐d‐xylulose‐5‐phosphate synthase (DXS) and bacterial phytoene synthase (crtB), mediated by the patatin‐type 1 promoter. Storage roots harvested from field‐grown plants accumulated carotenoids to ≤50 μg/g DW, 15‐ to 20‐fold increases relative to roots from nontransgenic plants. Approximately 85%–90% of these carotenoids accumulated as all‐trans‐β‐carotene, the most nutritionally efficacious carotenoid. β‐Carotene‐accumulating storage roots displayed delayed onset of postharvest physiological deterioration, a major constraint limiting utilization of cassava products. Large metabolite changes were detected in β‐carotene‐enhanced storage roots. Most significantly, an inverse correlation was observed between β‐carotene and dry matter content, with reductions of 50%–60% of dry matter content in the highest carotenoid‐accumulating storage roots of different cultivars. Further analysis confirmed a concomitant reduction in starch content and increased levels of total fatty acids, triacylglycerols, soluble sugars and abscisic acid. Potato engineered to co‐express DXS and crtB displayed a similar correlation between β‐carotene accumulation, reduced dry matter and starch content and elevated oil and soluble sugars in tubers. Transcriptome analyses revealed a reduced expression of genes involved in starch biosynthesis including ADP‐glucose pyrophosphorylase genes in transgenic, carotene‐accumulating cassava roots relative to nontransgenic roots. These findings highlight unintended metabolic consequences of provitamin A biofortification of starch‐rich organs and point to strategies for redirecting metabolic flux to restore starch production.

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Diallel analysis of provitamin A carotenoid and dry matter content in cassava (<i>Manihot esculenta</i> Crantz)

Cited by 24 publications

References 41 publications

Men and women’s perception of yellow-root cassava among rural farmers in eastern Uganda

Men and women’s perception of yellow-root cassava among rural farmers in eastern Uganda

Genetic Variation and Trait Correlations in an East African Cassava Breeding Population for Genomic Selection

Provitamin A biofortification of cassava enhances shelf life but reduces dry matter content of storage roots due to altered carbon partitioning into starch

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