HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hsu, F. H. Articles by Matches, A. G. Search for Related Content PubMed Articles by Hsu, F. H. Articles by Matches, A. G. Agricola Articles by Hsu, F. H. Articles by Matches, A. G.

Temperature Effects on Germination of Perennial Warm-Season Forage Grasses¹

Slow germination and low seedling vigor limit establishment of perennial warm-season forage grasses, and temperature is a major environmental factor influencing both processes. Therefore, three experiments were conducted to determine temperature effects on germination of big bluestem (BB) (Andropogon gerardi Vitman), caucasian bluestem (CB) [Bothriochloa caucasica (Trin.) C.E. Hubb.], indiangrass (IG) [Sorghastrum nutans (L.) Nash.], and switchgrass (SG) (Panicum virgatum L.), as well as an annual species, crabgrass (CG) [Digitaria sanguinalis (L.) Scop.]. In Exp. I and II seeds were chilled at 4°C for 2 weeks before the germination test. In Exp. I, germination temperatures were 15, 20, 25, 30, 35, and 30/20°C with one entry of each species, except for two of SG. In Exp. II, two to four entries of BB, IG, and SG were tested at 20, 25, and 30° C. In Exp. III, unchilled seeds of two strains of BB, IG and SG, and one of CB were germinated at 9, 12, 15, 20, 25, and 30°C. A logistic function was used to describe cumulative germination. Germination was maximum between 20 and 30°C for chilled seeds compared with 12 to 20°C for unchilled seeds because lower temperatures probably met partially the chilling requirement. Chilling also enhanced speed and percentage of germination of perennial species over unchilled seeds. Calculated minimum temperatures for germination of IG, BB, SG, and CB were 8.6, 8.9, 10.3, and 10.9°C, respectively. Time to reach 50% of final germination (Gt₅₀) decreased with increasing temperature. Further, Arrhenius plots of Gt₅₀ indicated a change in temperature response between 20 and 25°C for perennial species. True germinationrate (% day^-1) was maximum at Gt₅₀ for each treatment. Corrected germination rate index and GR₃₀ (reciprocal of Gt₅₀) were highly correlated and might be good indices to estimate speed of germination. The lower minimum temperatures for germination of IG and BB may allow these species to be planted earlier in spring than SG and CB.

Key Words: Physiological dormancy • Germination rate • Germination rate index • Corrected germination rate index • Germination kinetics • Threshold temperature • Logistic function • Arrhenius plot • Speed of germination • Big bluestem • Andropogon gerardi Vitman • Caucasian bluestem • Bothriochloa caucasica (Trin.) C. E. Hubb. • Indiangrass • Sorghastrum nutans (L.) Nash • Switchgrass • Panicum virgatum L. • Crabgrass • Digitaria sanguinalis (L.) Scop.

² Former graduate student (now associate research fellow, Dep. of Forage Crops, Taiwan Livestock Res. Inst., Hsinhua, Tainan, Taiwan, ROC); professor, Dep. of Agronomy, Univ. of Missouri, Columbia, MO, 65211; and professor, Dep. of Plant — Soil Science, Texas Tech Univ., Lubbock, TX 79409, respectively.

Received for publication November 14, 1983.

This article has been cited by other articles:

				I. C. Madakadze, K. A. Stewart, R. M. Madakadze, and D. L. Smith Base Temperatures for Seedling Growth and Their Correlation with Chilling Sensitivity for Warm-Season Grasses Crop Sci., May 1, 2003; 43(3): 874 - 878. [Abstract] [Full Text] [PDF]