Breaking primary dormancy in seeds of the perennial pasture legume tedera (Bituminaria bituminosa C.H. Stirt. vars albomarginata and crassiuscula). (17th December 2013)

• Record Type: Journal Article
• Authors: Castello, M.; Croser, J. S.; Lulsdorf, M. M.; Ramankutty, P.; Pradhan, A.; Nelson, M. N.; Real, D.
• Is Part Of: Grass and forage science. Volume 70:Number 2(2015:Jun.)
• Page Start: 365
• Page End: 373
• Publication Date: 2013-12-17
• Subjects: Grasses -- Periodicals; Forage plants -- Periodicals; Grasslands -- Periodicals; 633.2
• DOI: 10.1111/gfs.12107
• Languages: English
• ISSNs: 0142-5242

Abstract

<abstract abstract-type="main" id="gfs12107-abs-0001"> <title>Abstract</title> <p>Tedera (<italic>Bituminaria bituminosa</italic> vars. <italic>albomarginata</italic> and <italic>crassiuscula</italic>) is a perennial pasture species with agronomic characters ideally suited to Mediterranean climates. Tedera seed has a period of after‐ripening or primary dormancy typically lasting three months, which delays assessment and breeding of elite hybrid varieties. Temperature, chemical and mechanical methods were investigated in conjunction with <italic>in vitro</italic> culture to circumvent this dormancy period across a range of parental and hybrid genotypes. Temperature treatment of T5 (Tedera accession 5) and T48 (Tedera accession 48) alone was not sufficient to break dormancy (24.0% and 14.7% germination); however, when combined with soaking in gibberellic acid (GA<sub>3</sub>) and mechanical scarification resulted in 79.7% and 84.3% germination respectively. In an effort to further improve this result for valuable hybrid genotypes, we combined mechanical scarification with removal of seed coat after imbibition and <italic>in vitro</italic> culture on B5 medium until radicle emergence. This resulted in breaking dormancy from 96% to 100% of parent seeds and 100% of hybrid seeds. Hardening the germinated F<sub>1</sub> or F<sub>2</sub> seedlings 4 d after first transfer to <italic>in vitro</italic> culture resulted in 100% survival of plants to soil. This procedure is now used on a routine basis in the Australian tedera breeding programme.</p> </abstract>