Abstract
Crantz) and causing significant yield losses, there is a lack of comprehensive studies assessing resistance in the species' germplasm. This study aimed to evaluate the phenotypic diversity for resistance to anthracnose disease (CAD), blight leaf spot (BliLS), brown leaf spot (BLS), and white leaf spot (WLS) in cassava germplasm and to identify genotypes suitable for breeding purposes. A total of 837 genotypes were evaluated under field conditions across two production cycles (2021 and 2022). Artificial inoculations were carried out in the field, and data on yield and disease severity were collected using a standardized rating scale. The top 25 cassava genotypes were selected based on a selection index for disease resistance and agronomic traits. High environmental variability resulted in low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively) and moderate heritability for BliLS (h2 = 0.51). While the range of data for disease resistance was narrow, it was considerably wider for yield traits. Cluster analysis revealed that increased yield traits and disease severity were associated with higher scores of the first and second discriminant functions, respectively. Thus, most clusters comprised genotypes with hybrid characteristics for both traits. Overall, there was a strong correlation among aerial diseases, particularly between BLS and BliLS (r = 0.96), while the correlation between CAD and other diseases ranged from r = 0.53 to 0.58. Yield traits showed no significant correlations with disease resistance. Although the mean selection differential for disease resistance was modest (between -2.31% and -3.61%), selection based on yield traits showed promising results, particularly for fresh root yield (82%), dry root yield (39%), shoot yield (49%), and plant vigor (26%). This study contributes to enhancing genetic gains for resistance to major aerial part diseases and improving yield traits in cassava breeding programs.
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Claims 18
Claim · model-written summary
The top 25 cassava genotypes were selected for disease resistance and agronomic traits.
- Taxon
- cassava
Manihot esculentae0 - Material
- cassava genotypese0
- Outcome
- selectede0
- Value
- 25e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The top 25 cassava genotypes were selected based on a selection index for disease resistance and agronomic traits”
Claim · model-written summary
Anthracnose disease resistance had low heritability of 0.42.
- Taxon
- CassavaManihot esculentat0
- Outcome
- heritabilities (h2) for CADe0
- Direction
- lowe0
- Value
- 0.42e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively)”
e1“anthracnose disease (CAD)”
t0“Cassava”
Claim · model-written summary
White leaf spot resistance had low heritability of 0.34.
- Taxon
- CassavaManihot esculentat0
- Outcome
- heritabilities (h2) for CAD, WLS, and BLSe0
- Direction
- lowe0
- Value
- 0.34e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively)”
t0“Cassava”
Claim · model-written summary
Brown leaf spot resistance had low heritability of 0.29.
- Taxon
- CassavaManihot esculentat0
- Outcome
- heritabilities (h2) for CAD, WLS, and BLSe0
- Direction
- lowe0
- Value
- 0.29e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively)”
t0“Cassava”
Claim · model-written summary
Blight leaf spot resistance had moderate heritability of 0.51.
- Taxon
- CassavaManihot esculentat0
- Outcome
- heritability for BliLSe0
- Direction
- moderatee0
- Value
- 0.51e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“moderate heritability for BliLS (h2 = 0.51)”
t0“Cassava”
Claim · model-written summary
Disease resistance varied over a narrow range.
- Taxon
- CassavaManihot esculentat0
- Outcome
- range of data for disease resistancee0
- Direction
- narrowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the range of data for disease resistance was narrow”
t0“Cassava”
Claim · model-written summary
Yield traits varied over a wider range than disease resistance.
- Taxon
- CassavaManihot esculentat0
- Outcome
- yield traitse0
- Direction
- widere0
- Comparator
- disease resistancee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it was considerably wider for yield traits”
e1“the range of data for disease resistance was narrow”
t0“Cassava”
Claim · model-written summary
Higher first discriminant-function scores were associated with increased yield traits.
- Taxon
- CassavaManihot esculentat0
- Outcome
- yield traitse0
- Direction
- increasede0
- Qualifier
- firste0
- Comparator
- higher scorese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased yield traits and disease severity were associated with higher scores of the first and second discriminant functions, respectively”
t0“Cassava”
Claim · model-written summary
Higher second discriminant-function scores were associated with increased disease severity.
- Taxon
- CassavaManihot esculentat0
- Outcome
- disease severitye0
- Direction
- increasede0
- Comparator
- higher scorese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased yield traits and disease severity were associated with higher scores of the first and second discriminant functions, respectively”
t0“Cassava”
Claim · model-written summary
Most clusters had hybrid characteristics for yield traits and disease severity.
- Taxon
- CassavaManihot esculentat0
- Outcome
- hybrid characteristics for both traitse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“most clusters comprised genotypes with hybrid characteristics for both traits”
t0“Cassava”
Claim · model-written summary
Brown and blight leaf spot resistance were strongly correlated, with r = 0.96.
- Taxon
- CassavaManihot esculentat0
- Outcome
- correlation among aerial diseasese1
- Value
- r = 0.96e0
- Comparator
- BLS and BliLSe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“particularly between BLS and BliLS (r = 0.96)”
e1“strong correlation among aerial diseases”
t0“Cassava”
Claim · model-written summary
Anthracnose resistance correlated with other diseases at r = 0.53 to 0.58.
- Taxon
- CassavaManihot esculentat0
- Outcome
- correlation between CAD and other diseasese0
- Value
- r = 0.53 to 0.58e0
- Comparator
- other diseasese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the correlation between CAD and other diseases ranged from r = 0.53 to 0.58”
t0“Cassava”
Claim · model-written summary
Yield traits were not significantly correlated with disease resistance.
- Taxon
- CassavaManihot esculentat0
- Outcome
- correlations with disease resistancee0
- Comparator
- Yield traitse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield traits showed no significant correlations with disease resistance”
t0“Cassava”
Claim · model-written summary
Selection differentials for disease resistance were modest, from -2.31% to -3.61%.
- Taxon
- CassavaManihot esculentat0
- Outcome
- mean selection differential for disease resistancee0
- Value
- between -2.31% and -3.61%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mean selection differential for disease resistance was modest (between -2.31% and -3.61%)”
t0“Cassava”
Claim · model-written summary
Selection on fresh root yield gave an 82% differential.
- Taxon
- CassavaManihot esculentat0
- Outcome
- fresh root yielde0
- Value
- 82%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fresh root yield (82%)”
t0“Cassava”
Claim · model-written summary
Selection on dry root yield gave a 39% differential.
- Taxon
- CassavaManihot esculentat0
- Outcome
- dry root yielde0
- Value
- 39%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“dry root yield (39%)”
t0“Cassava”
Claim · model-written summary
Selection on shoot yield gave a 49% differential.
- Taxon
- CassavaManihot esculentat0
- Outcome
- shoot yielde0
- Value
- 49%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot yield (49%)”
t0“Cassava”
Claim · model-written summary
Selection on plant vigor gave a 26% differential.
- Taxon
- CassavaManihot esculentat0
- Outcome
- plant vigore0
- Value
- 26%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plant vigor (26%)”
t0“Cassava”