National Jointed Goatgrass Research Program

 

Progress Report-2002

NOTICE
The following is a progress report containing preliminary data and results that may be modified by future research.
Please contact the listed authors
or Extension Coordinator for additional information.

 

TITLE:    Impacts of spring crops on jointed goatgrass biology and management

PERSONNEL:    Carol Mallory-Smith, Weed Scientist, Oregon State University
                            Lynn Fandrich, Graduate Research Assistant, Oregon State University

TIMELINE:     Initiation date -- July 1, 2001.  Termination date -- June 30, 2003.  Project will finish by June 30, 2004.  No additional funds are requested.

ORIGINAL HYPOTHESIS:  Within a weed population, there are cohorts that vary in genetic material and so vary in response to environmental conditions.  Populations of jointed goatgrass will evolve to establish and produce seed in spring crops.

SUMMARY OF PROGRESS:  'Spring' populations of jointed goatgrass were considered less dormant than ‘winter’ populations.  Spikelet mass was not an adequate predictor of germination potential.  ‘Spring’ jointed goatgrass populations grown at Corvallis were more dormant than ‘spring’ Pendleton and Moro populations.  Environmental conditions during seed development may affect levels of post-harvest dormancy in jointed goatgrass.

OBJECTIVES:

Objective 1.     Compare jointed goatgrass seed collected in spring crops with jointed goatgrass seed collected in winter wheat.

EXPERIMENTAL DESIGN:  Spikelets were harvested from plants sown with 2001 collections in nurseries at Pendleton, Moro, and Corvallis, Oregon.  Germination assays were conducted on freshly harvested ‘winter’ and -20 C stored ‘spring’ nursery-produced spikelets.  Three samples of 20 jointed goatgrass spikelets were placed on two blotter papers in germination boxes wetted with 20 ml deionized water and covered.  Each jointed goatgrass sample contained four long-awned or terminal spikelets and 16 non-terminal spikelets.  Growth chambers were set to 30/20, 25/25, 25/15 and 15/15 day/night C and 16 hr photoperiod.  Germination was defined as the presence of 3 mm radicle outside the glumes.  Germination was recorded every two days beginning on day 1 and continuing through day 7.  Additional water (approximately 0.5 ml) was added to germination boxes as needed when germination data were recorded.

PROGRESS/CONCLUSIONS:  Since conditions under which parent plants are grown influence seed size (Datta et al. 1970) and may influence germinability, populations were grown under similar environmental conditions to maximize expression of genetic potential. ‘Winter’ and ‘spring’ jointed goatgrass populations harvested from 2002 nurseries did not differ in spikelet mass (Fig. 1).  Mass of 100 spikelets ranged from 3.92 grams for the ‘spring’ populations grown at Pendleton to 4.53 grams for ‘winter’ populations grown at Moro.  All recorded spikelet masses from 2002 nursery-populations were higher than field-population masses recorded in 2001. 

‘Winter’ and ‘spring’ jointed goatgrass populations did not germinate after seven days at 30/20 C (data not shown), but germinated at temperatures of 25/25, 25/15 and 15/15 C (Fig. 2).  At high temperatures, germination among populations grown at the three nursery locations was not different.  However, the Corvallis-produced ‘winter’ seed always germinated less than Moro and Pendleton produced seed, and germinated significantly less at 15/15 C.    Environmental conditions during seed development may affect levels of post-harvest dormancy in jointed goatgrass but additional research is necessary. 

When [seed] dormancy is induced, the temperature range over which the seeds can germinate becomes narrower (Karssen 1982; Vegis 1964). Since more spikelets germinated at 15/15 C and 25/15 C in 'spring' populations grown at Moro and Pendleton, 'spring' populations may be considered less dormant than ‘winter’ populations (Fig. 2c, d, e and f).

Greenhouse and laboratory studies will be conducted in 2004 to evaluate additional germination requirements, measure seed production per plant and quantify vernalization requirements for 'spring' and 'winter' populations.

LITERATURE CITED:

Datta, S. C., M. Evenari and Y. Gutterman. 1970. The heteroblasty of Aegilops ovata L.  Israel J. of Botany. 19:463-483.

Karssen, C. M. 1982. Seasonal patterns of dormancy in weed seeds. pp. 243-270 in A. Khan, ed.  The physiology and biochemistry of seed development, dormancy and germination.  A. Amsterdam:  Elsevier Biomedical Press.

Vegis, A. 1964. Dormancy in higher plants. Ann. Rev. of Plant Phys. 15:185-224.

PUBLICATIONS:

Fandrich, L. and C. Mallory-Smith.  2003.  Germination response of spring and winter cohorts of jointed goatgrass (Aegilops cylindrica).  WSWS In press.

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