Description

A germplasm collection of the Medicago sativa complex was evaluated to select genotypes possessing traits possibly conferring adaptation to grazing. Deep-crowned plants, either creeping-rooted or rhizomatous, were found with different frequencies, in all “taxonomic” groups examined. Although belonging to subsp. sativa, “mielga” wild populations from Spain were closer to subsp. falcata for morpho-physiological traits. Deep-crowned plants could be categorised into four top-growth models, to which corresponded a fairly distinct underground morphology: three were rhizomatous and one creeping-rooted. Cultivars selected for creeping-rootedness did not outyield rhizomatous populations of subsp. x varia which, in turn, had better spreading ability. In a subsequent evaluation, clones from selected rhizomatous genotypes had higher yield and better spreading ability than those from selected creeping genotypes. Under the given conditions, expression of creeping-rootedness was always erratic. The results point to the opportunity to pay greater attention to rhizomatous types in breeding grazing-tolerant cultivars.

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Selecting Lucerne (Medicago Sativa Complex) for Traits Conferring Adaptation to Grazing

A germplasm collection of the Medicago sativa complex was evaluated to select genotypes possessing traits possibly conferring adaptation to grazing. Deep-crowned plants, either creeping-rooted or rhizomatous, were found with different frequencies, in all “taxonomic” groups examined. Although belonging to subsp. sativa, “mielga” wild populations from Spain were closer to subsp. falcata for morpho-physiological traits. Deep-crowned plants could be categorised into four top-growth models, to which corresponded a fairly distinct underground morphology: three were rhizomatous and one creeping-rooted. Cultivars selected for creeping-rootedness did not outyield rhizomatous populations of subsp. x varia which, in turn, had better spreading ability. In a subsequent evaluation, clones from selected rhizomatous genotypes had higher yield and better spreading ability than those from selected creeping genotypes. Under the given conditions, expression of creeping-rootedness was always erratic. The results point to the opportunity to pay greater attention to rhizomatous types in breeding grazing-tolerant cultivars.