High levels of diversity for seed and forage production exist in Cullen australasicum, a potential new perennial forage legume for dry environments in southern Australia

Abstract

Abstract. The seed and forage production of a diverse group of the perennial forage legume Cullen spp., collected in southern Australia, was assessed with the aim of discovering diversity for exploitation in future breeding programs. Eighty ecotypes were assessed at the Waite Institute in South Australia, using replicated, spaced-plant field trials, between 2008 and 2012. Seed production in collected ecotypes of Cullen (Expt 1) ranged from 0 to 485 kg ha -1 for windrowed seed yield and from 0 to 790 kg ha -1 for total seed yield, which included vacuum-harvested seed from pods that had fallen to the ground. Individual plants were selected for seed production from their original populations, and the seed and fodder production of their progeny was evaluated in a further field experiment (Expt 2). Moderate to high heritability estimates were recorded for seed production traits. Seed production in progeny families ranged from 0 to1 423 kg ha -1 and was highly correlated with the number of seeds per inflorescence (r = 0.85) and forage yield (r = 0.59). Edible biomass, measured using the Adelaide visual appraisal method, ranged from 50 to 906 g dry weight (DW) plant -1 in parent ecotypes and from 404 to 1248 g DW plant -1 in the selected family progenies. Disease infection with anthracnose (Colletotrichum trifolii) caused considerable damage to plants in Expt 1, resulting in the death of all plants of 10 ecotypes, and infection with Alfalfa mosaic virus in Expt 2 was linked to the death of 67 individuals. The results are discussed in relation to breeding C. australasicum for increased seed yield and disease resistance to overcome these deficiencies as barriers to commercial adoption.

Agro-morphology and forage nutritive value of white prairie clover [Dalea candida(Michx.) Willd.] populations native to the Canadian prairies

“…Grimes], a potential new perennial forage legume for dry environments in southern Australia, Humphries et al (2014) estimated moderate to high heritability for seed production traits. In their study, phenotypic selection of plants resulted in a 193% increase in potential seed productivity and 38% increase in potential edible biomass productivity (Humphries et al 2014). The large phenotypic variation exhibited by white prairie clover populations is similar to many other native perennials (Mellish et al 2002;Ferdinandez and Coulman 2004;Liu et al 2013b), which holds great promise for selection gain on desirable traits.…”

Productivity and nutritional value of 20 species of perennial legumes in a low‐rainfall Mediterranean‐type environment in southern Australia

“…Seed production issues also constrain adoption of birdsfoot trefoil and Caucasian clover (Rolston 2003; Hill & Mulachy, 1994). Cullen is a broadly adapted Australian native that occurs naturally over widespread areas of Australia (Humphries et al., 2014), and has been shown to perform strongly in several other studies with lucerne as a comparison (see Bennett et al., 2011; Dear et al., 2007; Humphries et al., 2014). Despite this, the species has not been commercialized due to challenges with breaking seed dormancy to achieve reliable establishment.…”

Effects of Introduced and Indigenous Viruses on Native Plants: Exploring Their Disease Causing Potential at the Agro-Ecological Interface

“…Moreover, the 0.4% CMV seed transmission rate found in S. symonii raises the question of virus carry over from one generation to the next through seeds. Other evidence that introduced generalist viruses can greatly decrease foliage and seed production of Australian native plants comes from study of the impact of AMV on foliage and seed production in the native Australian legume Cullen australicum [78] . Thus, mixed virus infection in native plants growing at the interface between managed and natural vegetation is likely to further magnify reductions in competitive and reproductive capacities of infected plants.…”