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ABSTRACT
Considering the prevention of crop production, aimed at adaptation to climate changes, searching for or developing genotypes resistant to water deficit is a challenge for modern agriculture and a strategic goal of plant breeding. The objective of the study was to determine the effect of drought stress on the vigor of naked and husked oat (Avena sativa L.) cultivars. The studies concerned eight naked oat cultivars and two husked oat cultivars characterized by high germination capacity (above 95%). Seeds of naked oat cultivars showed susceptibility to varied thermal conditions during drought simulated by the use of polyethylene glycol (PEG) at a concentration of -1.5 MPa. An increase in temperature from 10 to 20 °C resulted in an average 37% increase in the number of normally germinating seeds, and in a more than 40% increase in germination rate, as well as in a 25% decrease in average germination time. A distinct increase in osmotic potential from -1 to -2 MPa during drought stress induction resulted in 15% decrease in vigor of husked cultivars measured by the percentage of normally developed seedlings. The vigor of oat cultivars, evaluated on the basis of electrical conductivity of exudates, was modified by genotypic variability. In naked cultivars, on average, 60% lower values were noted. The coefficients of correlation between electrical conductivity of exudates and germination capacity (r = -0.784··) or frequency of normally developed seedlings (r = -0.919··) confirm the highly significant interrelationship between the methods used for the evaluation of oat seeds under drought conditions.
Key words: Avena sativa, drought stress, husked oats, naked oats, seed vigor.
INTRODUCTION
Reproduction of sowing material characterized by high vigor seeds makes it possible to use fully the potential of cultivars only under appropriate growth and development conditions. Considering population growth, crop production is limited mostly by access to water, and in agriculture, the growing demand for this source of life is now 11 times higher than the attainable resources (FAO, 2011). By the middle of the present century in most countries of the world the annual average soil moisture (amount of water in the 10 cm soil layer just below the ground level) will be 1.6 mm lower, and surface water resources, due to decreased regular precipitation (especially in winter)...