RELATIONSHIPS BETWEEN PHENOTYPIC VARIATION AND CLIMATIC FACTORS AT COLLECTING SITES IN DURUM-WHEAT LANDRACES

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.