Aim. Assessment of the water-holding capacity of leaf blades and spikes of lines obtained by hybridization of bread spring wheat with synthetics Triticum durum Desf.–Aegilops tauschii Coss. as characteristics of their drought resistance. Identification of lines with a lower water-yielding capacity and accordingly with a higher water-holding capacity than that of the recurrent variety Kharkovskaya 26.
Results and Discussion. In all three years of research, in all samples, the moisture-yielding coefficient per unit of dry weight was higher for the leaf blade of the second leaf, lower (on average, 1.5 times) for the first leaf, and the smallest for the ear (on average, 2.0-5 , 7 times compared to the first sheet). This corresponds to the regularity of V.R. Zalensky on the increase in xeromorphism from the lower to the upper tiers of the plant. The moisture-yielding coefficient of the upper (flag) leaf is closely positively correlated with that of the second leaf: r = 0.98-0.99.
The leaf moisture-yielding coefficient correlates significantly, to an average extent, negatively with the yield of lines and the weight of grain per spike in unfavorable, arid 2015 and 2017 (r = −0.49 to −0.62) and tends to be negative in a more favorable 2016 (r = −0.26 to −0.30). The lines with a greater ability to retain leaf blades moisture during the period of caryopsis formation tend to higher yields and the formation of ears with a larger grain mass.
The moisture-yielding coefficient of the spike, in contrast to the leaf blades, in all three years positively correlated with the yield and grain weight per spike. The positive correlation of the ear moisture yield with the yield and ear productivity can be explained by an increase in the ear attracting ability in more productive forms. The lowest water-yielding capacity of the first (0.58-1.22) and (0.88-1.74) second leaves, corresponding to a greater water-holding capacity, in all the research years were the lines DK 30 GK 31 GK 34, GK 37, DK 39, DK 48, in which this indicator was less than that of the recurrent variety Kharkovskaya 26 (respectively, for the first leaf 1.26-1.43, for the second 1.77-2.08).
The moisture yield of an ear of these lines in 2015 was less than that of Kharkovskaya 26, in 2016 (excluding DK 48) and 2017 - more than that of this variety. Thus, by hybridization of bread spring wheat with synthetics, there were obtained the lines with a lower water-yielding capacity therefore a higher water-retaining capacity of leaves than in the recurrent variety Kharkovskaya 26. The average yield of the above-mentioned lines over the research years was from 245 to 297 g / m2, which is higher than that of Kharkovskaya 26. The average for the research years grain weight per an ear of the lines with low moisture yield was from 2.1 to 2.7 g, therefore, it was higher than in the variety Kharkovskaya 26. At the same time, the relationships of the moisture yield with the grain weight from an ear and yield are not unambiguous.
Conclusions. By crossing the spring wheat cultivar Kharkivska 26 with synthetics of the ABD genomic structure with subsequent backcrosses, lines with a lower moisture yield of the upper (0.58-1.22) and (0.88-1.74) second leaves were obtained than that of the recurrent cultivar - respectively 1,26-1,43 and 1,77–2,08, which corresponds to a higher water-holding capacity: DK 30, DK 31, DK 34, DK 37, DK 39, DK 48. There is an increase in water-holding capacity from the second leaf to the ear which corresponds to the regularity of V.R. Zalensky. The lines identified by the low moisture yield of leaf blades exceeded the recurrent variety Kharkovskaya 26 in yield and grain weight per ear. At the same time, relationships of the moisture yield with the grain weight from an ear and yield are not unambiguous.
Growth of Two Subtropical Ornamentals Using Coir (Coconut Mesocarp Pith) as a Peat Substitute
