The effect of drought and simulated rainfall on wheat (Triticum aestivum L.) seed and grain quality during development and maturation, including delayed harvest, were investigated with pot-grown plants harvested serially in a ventilated poly tunnel. Grain quality was assessed by seed mean dry weight (MOW), moisture content, HFN (Hagberg falling number), 50S (sodium dodecyl sulphate sedimentation), nitrogen content, sulphur content a nd seed size; seed quality by ability to germinate and subsequent air-dry seed storage survival. Developmental duration was the dominant factor influencing quality: HFN increased progressively and substantially from early seed filling to beyond harvest maturity in a sigmoidal pattern; 50S in a linear trend in 2012, but plateaued in 2013 from the end of seed filling; seed longevity in a curvi-linear trend (quantified by a polynomial) till harvest maturity; ability to germinate was maximal (100% normal germination) from 15-17 days before to 30-32 days after mass maturity (control). Stopping irrigation before seed filling ended reduced MOW and grain size, but increased HFN, 50S, germinability and seed longevity. Drought resulted in more rapid increase in HFN (14 days after anthesis > 21 DAA > 28 DAA > Control) and earlier attainment of maximum seed longevity. Ear wetting once close to harvest maturity reduced HFN considerably; thereafter it increased, though less than the control. Ear wetting reduced but root wetting increased HFN early in development, whereas both treatments at harvest maturity reduced seed and grain quality. Ear wetting reduced subsequent seed longevity immediately, but a period of re-drying in planta improved longevity - surpassing the control. Ear wetting (25-50mm) once at harvest maturity resulted in greater subsequent seed longevity than wetting for several days or >50mm. Hence direct and indirect and immediate and delayed effects of simulated rainfall were detected; drought improved and rainfall reduced HFN, but seed quality was increased by both.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:740775 |
| Date | January 2015 |
| Creators | Sapna, Kumari |
| Publisher | University of Reading |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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