Pear cultivars drought-resistance in the northern part of the Ukraines Lisosteppe

DOI: 10.35205/0558-1125-2018-73-149-153
UDC 632.112׃631.526.3׃634.13׃551.58

PEAR (PIRUS COMMUNIS L.) CULTIVARS DROUGHT-RESISTANCE IN THE NORTHERN PART OF THE UKRAINES LISOSTEPPE

Ju. B. KHODAKIVSKA, PhD
Institute of Horticulture, NAAS of Ukraine, 03027, Kyiv-27, 23, Sadova st., e-mail: kozulina_j1@ukr.net

The author presents the results of estimating the drought resistance according to the average indicators of the water deficit, water content, water-holding capacity and leaves turgor of the pear trees grown in the Northern part of the Ukraines Lisosteppe. The obtained results showed that in keeping with the moisture content in the leaf differ significantly from each other. In accordance with the comprehensive assessment, cvs were divided into groups depending on the drought resistance: high resistant Etude, Stryiska, Cheremshyna, Hoverla, resistant Khrystianka, Sonatina, Zolotovoritska, Roxolana, Vrodlyva, Vyzhnytsya, Smerichka, medium-resistant Lvivskyi Suvenir.
The important of drought resistance sign is water-holding capacity and the turgor restoration degree in dynamics, in certain intervals after the leaves drying. It is established that the pear leaves water-holding capacity is determined essentially by the variety characteristics and to a less extent depends on the retention time in the dehydration state. Comparing the water-holding capacity and the renewal degree turgor makes it possible to consider that in direct methods of the drought resistance determination correlate closely (r = 0.68). This enables the predictive the pear cultivars drought resistance according to accessory sings avoiding the trees stress dehydration of. The turgor renewal degree correlates with drought-resistance most fully (r = 0.76) after wilting, since the appearance of necrotic spots on leaves after drought indicates not only water deficiency but also protein disorder in plants.
The obtained data prove that drought resistance is a trait genetically determined. By the phenotype, it is displayed fully only after the plants have hardened under the natural drought. But, as we consider, the resistance severity is also conditioned by environmental factors stress degree.
Valuable for production are cvs that, are able to increase acutely the drought resistance degree in the adaptation process, recover quickly after drought and, most importantly, preserve the marketable crop, even under the leaf apparatus considerable damage. Therefore, the turgor degree recovery should be considered most important physiological indicator for pear and water deficit auxiliary.

Key words: pear, cultivar, water deficit, water content, water-holding capacity, turgor correlation, necrotic spots, albuminous decay, drought, photosynthesis, metab

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