No abstract

Some 15,000 to 10,000 years ago, humans started seeding and harvesting plants and maintaining animals in order to augment the food they obtained from wild-growing plants and hunting. These seemingly simple activities set in motion a long-term process that has led to the dominance of agriculture as we know it today. With the exception of a few remaining hunter-gatherer groups, agriculture has now become the most important source of food for most people. Agriculture is also a major source of feed for animals and of fiber. This transition from hunting-gathering to agriculture was without a doubt one of the most significant eras in the evolution of humans. It allowed food production on a more intensive and efficient scale than ever before, eventually leading to population increases, labor specialization (and especially a nonagricultural sector), the formation of villages, cities, and states, and the rise of more hierarchical societies and states (MacNeish 1991, Barker 2006). The late Professor J. R. Harlan (1917-1998) understood that the complexity of the biological, societal, and environmental changes involved in the transition to agriculture, as well as their antiquity of up to 10,000 years, necessitated a multidisciplinary approach if one is to understand the factors and processes that have led to the "neolithic revolution." Anthropologists, archaeologists, climatologists, ethnobiologists, geneticists, geographers, linguists, physiologists, and other practitioners all contribute to the field of crop evolution studies. J. R. Harlan also expressed concerns that the very development and spread of improved crop varieties were leading to losses in crop biodiversity, well before concerns about biodiversity became common knowledge. He made clear how the knowledge of evolutionary processes in crops facilitated the conservation of biodiversity and its use in the development of improved crop varieties. The vision of Professor Harlan was the inspiration for the first Harlan Symposium, which took place in 1997 in Aleppo, Syria, at the International Center for Agricultural Research in the Dry Areas (ICARDA). That symposium was remarkable because it brought together plant scientists and archaeologists

Polyacrylamide gel electrophoresis (PAGE) of storage proteins (prolamines) was used to screen 64 landraces of wheat and barley from Nepal and the YemenArab Republic and two cultivars for comparison. Altogether 3168 single seeds were examined and the advantages gained by using the vertical slab gel method were recognised. The extent of variation present within populations of landraces could be assessed easily and rapidly using the methods described. Differences in ploidy levels of wheats were detected by PAGE and investigated. Suggestions are made for improvements in sampling strategies in hilly terrain.

Information on the relationships between climatic features at collecting sites and morpho-physiological variation of genetic resources could enhance the understanding of evolutive adaptation patterns and assist germplasm collectors and users. In the present study, such relationships were investigated in durum wheat landraces of four countries of origin, viz. Ethiopia, Morocco, Syria, and Turkey, evaluated in northern Syria. Several relationships were found which mainly concerned drought stress and high temperature among climatic collecting variables and earliness of heading among agronomic traits. Higher drought and heat stress was associated with lower yield under moderately favourable conditions and better drought tolerance besides earlier heading in the Ethiopian landraces. Within the Turkish germplasm, the temperature level influenced both yield potential and earliness positively. Longer spike was associated with lower drought and heat stress at collecting sites in the Ethiopian and Syrian gene pools. In the latter germplasm, lower drought was also related closely to shorter stature and lower protein content. Overall morpho-physiological variation as summarized by the first axis of a principal components analysis was associated to climatic variables influencing drought and heat stress in the Ethiopian and Syrian germplasm and to maximum temperatures in the Turkish one.

A collection of accessions of cultivated emmer wheat, Triticum dicoccum, was evaluated for economically important traits at Tel Hadya in northern Syria. Useful variation among and within accessions was detected for agronomic traits, including a high number of productive tillers and protein content. The results from the disease screening nurseries indicated that T. dicoccum offers a good source of resistance to common bunt and yellow rust. Most of the accessions tested were, however, susceptible to late frost, which occurred in the second season. In the dry areas of West Asia and North Africa (WANA) available moisture in the soil is limited, and biotic and other abiotic stresses, such as terminal heat stress, reduce the grain yield to a considerable extent. The present study indicates that T. dicoccum has a large potential for use in improvement of durum wheat for WANA, where 80 % of the world's production of this crop is grown.