The effect of applications of different nitrogen types and potassium on seed quality and AR37 endophyte presence at different spikelet and floret positions of perennial ryegrass cv. Halo
Bibliographic record
Abstract
Nitrogen has been considered as an important nutrient in the terrestrial system. In the seed production of ryegrasses, one of the most popular pastures used in New Zealand and other temperate-zone areas, the application of nitrogen is responsible for improving seed yield and seed quality. Novel fungal endophytes are also now commonly used in perennial ryegrass pasture systems. The effect of different forms of nitrogen on seed quality and endophyte infection frequency and alkaloid concentration including spikelet/floret positional effects is also of interest to researchers. This study was designed to determine the effects of three nitrogen forms and potassium treatments (six in total) on the seed quality (purity, thousand seed weight (TSW), and germination) and AR37 endophyte presence in the offspring seedlings of the perennial ryegrass cv. Halo at three spikelet positions (top, middle and bottom). Also the effect of two nitrogen forms (nitrate and ammonium) at different floret positions was investigated. \nThe two nitrogen forms (urea and nitrate) with potassium had a poorer seed quality compared with the control and all nitrogen treatments applied without potassium. Nitrogen application (any form by itself) did not affect TSW of ‘Halo’, but a reduction was found under urea or nitrate with potassium. Also, seed germination percentages were not affected by nitrogen type when compared with the control, but urea with potassium gave a lower germination than the three nitrogen forms alone; and nitrate with potassium was lower than just the urea treatment. In the purity test, urea applied alone had a higher pure seed percentage than the control and the other nitrogen forms applied alone, but, again, the nitrogen with potassium application had the poorest performance in the test. On the other hand, none of these seed quality parameters differed among the three spikelet positions (top, middle and bottom). Both nitrogen and potassium application and different spikelet positions did not affect endophyte content in the offspring seedlings of ‘Halo’.In the minor experiment, where seven floret positions and only two nitrogen forms (ammonium (NH4+)and nitrate (NO3-)) were compared, the individual seed weights of Halo in florets3, 4, and 7 under nitrate application were higher than that under ammonium. The seed weight in floret 7 wasthe only position lower than floret 1 and 2 when ammonium was applied. The germination percentages were not affected by the two nitrogen forms, nor were different floret positions. Further, nitrogen application also did not alter empty seed percentages (in frequency), but the basal florets produced less empty seeds. Differences in endophyte content between ammonium and nitrate applications were found only in floret position 1 where nitrate reduced endophyte. Also amongst florets under nitrate there was higher endophyte content in floret positions 2, 4 and 7.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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".