Combining Ability and Heterosis of Selected Grain and Forage Dual Purpose Sorghum Genotypes
Bibliographic record
Abstract
Sorghum is an important food and feed source in mixed crop-livestock production systems where its dual usage is a preferred option, especially among the resource poor small-scale farmers. Attempts to improve fodder quality traits in maize have been at the expense of grain traits and vice versa, but other studies demonstrated that it was possible to select for high stem biomass without compromising the improvement of grain yields in sorghum. As a follow up to this effort, this study was undertaken to estimate the combining ability of grain and forage sorghum genotypes and determine heterosis for several traits as a criteria for improving dual purpose sorghum cultivars. Four grain and four forage sorghum cultivars were crossed to generate 23 crosses following the half diallel mating design scheme at Makerere University Agricultural Research institute Kabanyolo (MUARIK) in 2013. The crosses were evaluated at three locations in Uganda during two rainy seasons of 2014. Data were taken and analysed on leaf area, leaf-stem ratio, plant height, seed weight, grain yield, and biomass. Results indicated that the gene action for the traits under observation was controlled by both additive and non additive genetic effects. Majority of the parental lines had significant GCA estimates for all traits except line 20 for grain yield, lines 22 and 34 for plant height, line 35 for leaf-stem ratio, and line 22 for days to flowering. Significant (P ≤ 0.05) SCA estimates were prominent in most of the individual parental combinations for all traits except leaf area and leaf-stem ratio indicating the role of dominance gene action. Bakers ratio and heritability coefficients were > 52% for biomass, flowering duration and plant height indicating that genetic gains can be achieved by conventional breeding for the three traits. Heterosis in grain yield and biomass over both the mid and better parents was shown by more than half of the crosses studied. This study suggested that both inter and intra allelic interactions were involved in the expression of the traits.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".