Temperature Requirements for Mountain Rye, Hycrest Crested Wheatgrass, and Downy Brome Germination

Abstract

In thls study WC determined th8t mount8ln rye (Se& mont8am), cre8ted wheatgr8ss (Agropyron criatum X desertorum 'Hycreet'), 8nd downy brome (2?romus tectorum) h8ve slmllu germlnatlon temperature requirements and thus have tbc potentlal to germinate under slmllu soil temperature regimes, I future which could be rdv8at8geous for subsequent seedling competition of mount8ln rye or crested whe8tgr8ss 8giinst downy brome. Germhutlon tempenture profiles were compared uslng a thenno-gr8dlent germlrmtlon pl8te. Flfty-elx d&rent d8y/nlght tempenture reglmea were utlllzed for the comp8rlsons. The blvuirte spllne model WM found to be the best model for predlctlng germln8tlon-temper8ture response of the 3 species. Mountain rye 8nd downy brome produced high germhutlon under widely fluctu8tlng (20-300 C, 16 hr d8y/5-10" C, 8 hr nlgbt) temperature regimes with era&d whatgr8ss demonstmtlng 8n optimum genninrtlon temper rture over 8 10-20" C dry/250 C night regime. One of the 2 downy brome sources ev8lurted exhibited 8 much broader optimum germination tempenture nnge. However, the differences in germlnrtlon temperature profiles obtrined were not of 8 magnitude likely to be blologlc8lly or ecologlc8lly slgnlfiant due to the rel8tlvely high germln8tlon obt8lned over 8 wide nnge of fluctuating day/night temperrturea for 8ll3 species.

Comparison of Emergence Speed and Sterility in Two Sterile Annual Hybrid Cereal Grasses Developed for Use in Restoration

“…This variation between accessions within species might also explain why both B. tectorum and Elymus elymoides performed poorly at low temperatures in this study, despite having performed well in previous studies. Previous research has reported high variability in performance between accessions of both species (Buman & Abernathy 1988; Young et al 2003).…”

“…This is probably aided by germination at cold temperatures and resultant early seedling emergence. Buman and Abernathy (1988) found that B. tectorum achieved 29% germination with alternating night/day temperatures of 0/5°C for 3 weeks. Because early germination and emergence can result in larger plant size, which directly influences a plant’s ability to capture resources, it improves a plant’s ability to preempt resources from neighbors (Harper 1977).…”

“…Because early germination and emergence can result in larger plant size, which directly influences a plant’s ability to capture resources, it improves a plant’s ability to preempt resources from neighbors (Harper 1977). Several species commonly used in restoring B. tectorum ‐infested rangelands that also establish relatively high densities when sown with B. tectorum (Humphrey & Schupp 1999; T. Jones, 2006, USDA‐ARS Forage and Range Research Laboratory, personal communication) have also been shown to germinate at low temperatures, including: Bottlebrush squirreltail ( Elymus elymoides ), Hycrest crested wheatgrass ( Agropyron desertorum ), Bluebunch wheatgrass ( Pseudoroegneria spicata ), and Thickspike wheatgrass ( E. lanceolatus ) (Young et al 1981, 2003; Buman & Abernathy 1988; Jordan & Haferkamp 1989). Less research has been done on tolerance to moisture stress during germination, which may also promote early emergence in semiarid environments.…”

Value of Mountain Rye for Suppression of Annual Bromegrasses on Semiarid Mined Lands

“…Mountain rye established quickly after fall seeding and exhibited remarkable productivity during the following year because of its seed germination ecology (Buman and Abemethy 1988), coolseason phenology and high growth rates . Although first season growth was suppressed somewhat by the highest level of annual brome competition, rye productivity was sizable at ca.…”