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Accueil du site → Doctorat → Australie → 2011 → Grass pea (Lathyrus sativus cv. Ceora) : adaptation to water deficit and benefit in crop rotation

University of Western Australia (2011)

Grass pea (Lathyrus sativus cv. Ceora) : adaptation to water deficit and benefit in crop rotation

Gusmao, Marcal

Titre : Grass pea (Lathyrus sativus cv. Ceora) : adaptation to water deficit and benefit in crop rotation

Auteur : Gusmao, Marcal

Université de soutenance : University of Western Australia

Grade : Doctor of Philosophy (PhD) 2010

Résumé
[Truncated abstract] Grass pea (Lathyrus sativus cv. Ceora) is a multipurpose grain legume with an indeterminate growth habit. Adaptation of grass pea to water deficits and its potential rotational benefits in the Mediterranean-type environment of southern Australia are not well understood. The first objective of the thesis was to identify adaptation mechanisms of grass pea to water deficits. This was done by imposing water deficit during the reproductive period on plants grown in pots in a glasshouse. In the first experiment, a moderate water deficit was imposed on Ceora and a well-adapted field pea (Pisum sativum cv. Kaspa), by reducing soil water content from 80 to 50% field capacity (FC) during seed filling. Water deficit decreased pre-dawn leaf water potential (Ψ) of Ceora and Kaspa, as well as stomatal conductance (gs) of Ceora, but no reduction in photosynthesis occurred. Water deficit reduced green leaf area of Ceora resulting in 30 and 24% reduction in plant dry mass and seed yield at maturity, respectively. Seed size and harvest indices (HI) of Ceora did not differ between the treatments. Ceora produced more dry matter than Kaspa in both treatments, but produced 22 (control) and 33% (water deficit) lower seed yields. Kaspa had higher HI and water use efficiency for grain than Ceora. In the second experiment, severe water deficit was imposed on Ceora plants by withholding water from first flowering until Ψ fell to -3.12 MPa, when the plants were rewatered. At maturity, dry matter, seed yield and harvest index decreased by 60%, 87% and 67%, respectively, compared with the control. Flower production stopped at Ψ -1.8 MPa. At Ψ=-1.5 MPa, only 25% of the total flowers produced filled pods (compared with 95% in the control) and the rest aborted as flowers (48%) and pods (27%). Filled pods had more aborted ovules resulting in 29% less seeds per pod than the control. Water deficit reduced pollen viability (from 88 to 75%) and germination (from 53 to 28%) compared with the control. Of the germinated pollen, pollen tubes reaching the ovary were reduced by water deficit from 70 to 39% compared with the control. Seed size did not differ between the treatments. A second objective of the thesis was to assess the effect of a grass pea crop on soil N and P availabilities, and the persistence of this effect over the summer period...

Mots clés : Photosynthesis ; Harvest index ; Wheat P uptake

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Page publiée le 7 novembre 2011, mise à jour le 8 juin 2017