Yield and traits of leaves assimilation surface of winter wheat

Aim. To determine markers of drought tolerance based on the analysis of the traits leaves assimilation surface in 6 va- rieties of winter wheat with near drought tolerance under conditions of field drought in the Forest-Steppe of Ukraine. Methods. Traits of leaves assimilation surface was determined used field, morphometric, phenological and spectrophotometric methods. Results. Under conditions of field drought during the grain filling period the dry weight of flag leaf and of all green leaves of the main shoot of 2 high-yielding varieties (Kyivska 17 and Horodnytsia) at anthesis and milk ripeness were higher, than that of 4 others on average over 3 years. The specific weight of the flag leaves of the main shoot and chlorophyll content slightly differed in the studied varieties. The variability of the dry weight of flag leaf and of all green leaves of the main shoot of winter wheat varieties at anthesis and at milk ripeness was greater than the variability of their chlorophyll content it was found. A close correlation between the dry weight of flag leaf at anthesis and at milk ripeness, as well as all green leaves, with the yield (r = 0.658–0.837) was established. Conclutions. The higher yield of winter wheat varieties with a higher leaf dry weight under drought conditions may be due to the formation of a more amount of photoassimilates, which can be used both for root growth (water deficit avoidance strategy) and for the storage of reserved assimilates in the stem (strategy of create reserves for further filling of grain). The dry weight of flag leaf of the main shoot at anthesis can be used as a morphometric marker of drought tolerance, given the close correlation with the yield and the simplicity and convenience of determinations in the field.