Timing of stress and yield determination in maize (Zea Mays L.)
Bibliographic record
Abstract
Yield loss in maize (Zea mays L.) is well known to be caused by abiotic and biotic stresses. Previous studies have focused, primarily, on the determination of yield loss as a result of stress occurring during the critical reproductive stages, that is, around silking and the grain fill period. No studies have assessed yield loss caused by differing stresses that occur early during the vegetative phase. Studies were conducted during 2012-13 under controlled and field conditions at two locations in Ontario, Canada. Early season stresses (i.e., up to V9 stage of growth) included drought, light quality (red to far red) and early high-plant density while high plant density was considered a season long stress. In this thesis, the hypothesis was tested that if yield is reduced in response to early season stress, then, resource capture and resource utilization will be reduced proportionally. The relationship between plant dry matter and floret number follows the classic relationship with a minimum dry matter level required and a plateau. Not all stresses impacted these relationships in the same manner. These results confirm that floret number in maize is established well in advance of flowering and also suggests that floret number is related to plant dry weight sampled between V7 to V9-10 stage of growth. Yield loss in the drought and early high-plant density stress treatments, was caused by reductions in dry matter accumulation and kernel number. Growth rates around silking were reduced and flowering delayed in response to early season stress which explained reductions in kernel set. While ASI was only lengthened by early high density, HI remained unchanged in response to early season stress. Season-long high plant density stress resulted in reduced plant dry matter, and kernel number. Plants presenting low dry matter accumulation in each stage of growth exhibited lower floret and kernel number. Barren plants at maturity showed very low or no dry matter accumulation during the grain filling period. Overall, early season stress reduced resource capture only, while season long stress defined as high plant density reduced both resource capture and utilization.
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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 | 0.000 | 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) | 0.000 | 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".