Submitted to: Seed Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/1998
Publication Date: N/A
Interpretive Summary: Common dallisgrass is a warm-season forage grass which is important in the southeastern United States. However, dallisgrass seed is usually of poor quality, and germination is very low. One reason for this poor seed quality is the presence of a fungus called ergot. Because of its unusual method of reproduction (called apomixis), dallisgrass seed quality cannot be improved by normal breeding methods. One method to improve seed quality would be to incorporate genes (from relatives of dallisgrass with high seed quality) into common dallisgrass. We compared seed quality of common dallisgrass and three dallisgrass types which have been introduced from South America. One of the types, called yellow-anthered dallisgrass, has high seed quality while the other two types are similar to common dallisgrass in seed quality. For all the dallisgrass types, treatment of seed with concentrated sulfuric acid improved germination, although the effect on germination was more pronounced in seed which had been harvested and stored for one or two years. Results of this study indicate that yellow-anthered dallisgrass could be a source of genes for higher seed quality. Also, we found that for all the dallisgrass types, seed quality varies greatly from year to year.
Technical Abstract: Common dallisgrass (Paspalum dilatatum Poir.) is an important forage grass in the southeastern United States. It has poor seed fertility which limits its use. The objectives of this study were to determine effects of storage temperature and treatments on the viability and germinability of seed from four dallisgrass biotypes (common, Uruguayan, Uruguaiana and yellow-anthered). Seed of the four biotypes were harvested from field-grown plants in June 1988, October 1990, and June 1991. Immediately after harvest, untreated and sulphuric acid-treated seed were germinated. Viability of yellow- anthered dallisgrass seed was consistently the highest (mean of 90%), while the viability of common dallisgrass never exceeded 38%. Viability of the other two biotypes was similar to common. Seed lots collected in 1988 were divided into two subsamples and stored either at room temperature (26 C) or at 7oC. Germination was lower in seed stored for two years at 7oC than at room temperature; however, a 1-minute sulphuric acid treatment improved germination of seed stored at 7oC. Results indicate that (1) storage at room temperature (26 C) was preferable to storage at 7oC; (2) yellow-anthered dallisgrass had high seed viability, while values for the other three biotypes were similar; and (3) acid treatments were useful in increasing germination of both fresh and stored seed.