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Variability in six major characteristics of 12 annual medic species

E.J. Crawford

South Australian Department of Agriculture, Box 1671 G.P.O. Adelaide

Only five annual medic (Medicago spp.) have cultivars that have made a significant contribution in farming systems in southern Australia. This paper summarises the variability in 7063 accessions of species currently regarded as the most promising for future cultivar development.

Method

Twenty-five seedlings of accessions of predetermined species were planted in the field at Parafield Plant Introduction Centre during the period 1968-82. They were compared with the commercially available cultivar appropriate to each species; M. truncatula cv. Jemalong being used as the control for all non-commercialised species.

Results and Discussion

The five commercialised species were represented by 3799 accessions. Table I illustrates the potential for the development of more vigorous, early flowering and high seed yielding cultivars. The outstanding range of variability within M. intertexta, M. polymorpha, M. tornata and M. truncatula accessions augurs well for future cultivar development. The relatively low seed production of the late flowering species M. murex, M. rigidula and M. turbinata reduces their potential. The large range in levels of hard seededness in M. polymorpha, a very widespread naturalised species in southern Australia is significant as local ecotypes regenerate spasmodically. Excluding the spineless podded species and the short spiced M. turbinata, there is a big range in levels of pod spininess; species such as M. aculeata, M. littoralis, M. murex, M. polymerpha, M. rigidula, M. tornata and M. truncatula all having spineless accessions.

Table 1 - Variability in six characteristics of 12 annual Medicago species at Parafield, South Australia, 1968-82.

These desirable characteristics can be combined with insect pest and disease -resistance in breeding and developing new synthetic hybrids in the future.

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