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Accueil du site → Doctorat → États-Unis → 1983 → Adaptation of crambe species to limited water supply under arid conditions

New Mexico State University (1983)

Adaptation of crambe species to limited water supply under arid conditions

CHAN CASTANEDA, JOSE LUIS

Titre : Adaptation of crambe species to limited water supply under arid conditions

Auteur : CHAN CASTANEDA, JOSE LUIS

Université de soutenance : New Mexico State University

Grade : Doctor of Philosophy (PhD) 1983

Résumé
Adaptation of Crambe spp. to limited water supply was studied in eight greenhouse and three field experiments. The objectives were to develop knowledge about crambe’s response to drought and to develop screening techniques for drought resistance. Under greenhouse conditions, plant water relations were examined using relative water content (RWC), kinetics of rehydration (KR), leaf water potential (LWP), leaf osmotic potential (LOP), leaf diffusion resistance (LDR), transpiration (T), and plant dry weight (DW). Two cultivars ’Meyer’ and ’Prophet’ were used. Drought intensities were evaluated at different plant stages. The RWC technique was found adequate for studying water relations in crambe. Sampling should consider uniform leaf age and 10 leaf discs of 8 to 12 mm in diameter. LDR and T were good indicators of plant stress when soil water potential (SWP) was beyond -0.3 to -0.6 MPa. Drought reduced LA and DW. Under drought, Prophet conserved more water than Meyer as indicated by higher RWC, LOP, and LDR, and decreased T. In 1981 (Exp. F-1), 20 genotypes were field evaluated, under the line source sprinkler system. Five equidistant positions from the sprinkler line represented irrigation levels (IL), with two replications along the line. Genotypes were randomized with IL. The matric SWP was used to evaluate plant responses (RWC, KR, LDR, T, LOP, LA, and DW), whereas the total amount of water applied after establishment was used to evaluate seed yield and water use efficiency. Experiment F-2 (1982) was similar to Exp. F-1 except for the reduction to 10 genotypes and 3 IL. Experiment F-3 was used to evaluate the effect of irrigation applied at different growth stages. Evaluation included plant growth, water relations and seed yield of the cultivars, Meyer and Prophet. Experiments F-1 and F-2 indicated variation among genotypes under drought. Six genotypes had significantly delayed development as drought increased. Prophet had the highest seed yield which increased with increasing IL. In Exp. F-3, Prophet grew more than Meyer. Seed germination of seed collected from Exp. F-1 was very poor, which suggested a restrictive factor in crambe production under the conditions of this study.

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Page publiée le 1er janvier 2015, mise à jour le 11 novembre 2018