M

10,000

Grasses appear Maize and rice diverge Oats and barley diverge First record of Loliinae (temperate grasses) Split between Festuca and Lolium Diversification of Lolium spp. Speciation in the genus Triticum Appearance of Lolium temulentum in the Fertile Crescent; beginning of temperate agriculture Earliest emmer, einkorn remains Earliest bread wheat remains Darnel, wheat preserved together

Inda et al. 2008). Most estimates date divergence of the genus Lolium at around 2-3 mya, and its differentiation into species about 1 mya (Charmet et al. 1997; Inda et al. 2008), which, significantly, is similar to the timing reported for speciation in the genus Triticum (Stebbins 1981). Inda et al. (2008) located the centre of origin of L. perenne and L. rigidum in the pan-Mediterranean SW Asia biogeographical area and suggest an interglacial Pleistocene origin for these most recently evolved Mediterranean forage ryegrasses.

Senda et al. (2005c) used DNA markers to determine the genetic relationships between 48 geographically diverse populations of L. temulentum collected from eight countries. They inferred from their phylogenetic analyses that the species originated between Southwestern Asia and the Mediterranean basin. Darnel evolved out of the centre of diversity of the genus Lolium (Balfourier et al. 2000), probably around 10,000 years ago, coincident with the beginnings of temperate cereal cultivation (Archatlas 2006). Examination of Egyptian and middle-eastern prehistoric sites dating from earlier than 2000 BC has revealed darnel grains amongst cereal residues (Tackholm et al. 1973; McCreery 1979). Table 2 presents a tentative timeline for the evolutionary origin of L. temulentum, based on evidence from molecular phylogeny, palaeontology and archaeology. The spread of Lolium spp. along three major routes from the Fertile Crescent region to Europe and North Africa is shown in Fig. 2.

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