Provenance hybridization in a diallel mating scheme of maritime pine (<i>Pinus pinaster</i>). II. Heterosis
Bibliographic record
Abstract
Maritime pine (Pinus pinaster Ait.) is a species characterized by a discontinuous natural range with populations as a rule of small size and growing in heterogeneous environments. Ten provenances belonging to the three biosystematic groups of the species (Atlantic, Mediterranean, and North African) were crossed using a diallel scheme. Parental provenances and their hybrids were tested and measured for height growth at age 1, 2, 3, 8 and 13, as well as for insect resistance and stem crookedness in a trial in southwestern France. The results show a decrease in the variance of heterosis for height growth with age. Heterosis measured as the relative superiority of the hybrid to the midparent varies from -10% to 42% at age 1 and between 2 and 20% at age 13. There is no age effect on the mean value of heterosis, which amounts to 9.7% at age 1 and 8.4% at age 13. The value of heterosis was then compared with the genetic distance of parental provenances measured with various traits and markers (phenotypic traits, terpenes, isozymes, denaturated proteins). There was a weak but significant positive correlation between genetic divergence based on markers and heterosis for height at all ages. These relations were confirmed when the level of heterosis was compared for hybrids clustered according to the subdivision of the species in three major groups. The results are in agreement with theoretical analysis of heterosis and suggest that there is a disequilibrium between loci controlling height growth and neutral loci at the between population level. No significant relationship between levels of heterosis and stem crookedness or insect resistance was detected.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".