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Texas Tech University (TTU) (1995)

Establishment and stress tolerance of buffalograss

Gaitan-Gaitan, Fernando

Titre Establishment and stress tolerance of buffalograss

Auteur : Gaitan-Gaitan, Fernando

Université de soutenance : Texas Tech University (TTU)

Grade : Doctor of Philosophy (PhD) 1995

Résumé
Buffalograss [Buchloe dactyloides (Nutt.) Engelm.j is a well adapted species and one of the most drought tolerant grasses native to the semi-arid Southern Great Plains. Successful establishment of buffalograss is often limited by date of planting, seeding rate and type of seed. Buffalograss response to drought stress is to enter dormancy with very rapid regrowth when water becomes available. Characterization of other phenotypic responses to drought have not been established due to the lack of a suitable drought stress tolerance test. This dissertation presents the results of several studies conducted at the Texas Tech Plant Laboratory in Lubbock, Texas during three years to determine the optimal planting dates as well as seeding rates and type of seed to use. A modified tray system was designed to test buffalograss seedlings at two drought stress levels. Results indicated that when the cultivars ’Comanche’ and Texoka’ were used, optimal dates to obtain turfs with good stand density and quality are from mid May to mid July. Caryopses always produced higher stand establishment two and four weeks after planting. Experiments conducted to determine the optimal seeding rates and type of seed using ’Comanche’ buffalograss indicated that rates of 1125 to 1875 caryopses m^"^ gave optimum stand establishment and turf quality. Caryopses had a faster emergence and had less seedling mortality than burrs. However, final density and turf quality were not affected by type of seed and planting rate . A test to assess the drought tolerance of buffalograss seedlings was designed modifying a PEG-based tray system used to measure drought tolerance in forage grasses. The modified test uses variable day/night temperatures and an open container to allow constant air movement at leaf level. After tests were performed on over 1000 seedlings in each of four populations, no significant differences between drought stress levels or populations were found. Seedling survival ranged from 0.6 to 1.5 percent measured after plants were rewatered. The system proved to be useful for buffalograss seedling screening with adequate calibration for type of soil used and chamber conditions.

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