DROUGHT STRESS RESPONSES OF ALFALFA (MEDICAGO SATIVA L.) BREEDING POPULATIONS

The objectives of this research were to determine the effect of drought stress on yield in 23 alfalfa breeding populations and one cultivar, to evaluate the relationships between long-term alfalfa yields in second and third year of production and total precipitation during the alfalfa growing season, to screen and select breeding populations with high yield potential in drought conditions. The study was conducted in two consecutive years (2011 and 2012) at the experimental field of the Agricultural Institute Osijek, Croatia. The field trial was arranged in a randomized complete block design with four replications. Populations and the cultivar were planted in plots with size of 7.2 m(2) in sowing rate of 15 kg ha(-1). The yields of green mass and dry matter were determined in the second and third growing seasons, where in each year of the investigation experiment was cut off five times. Breeding populations ABP 13 obtained the highest average yield of green mass of dry matter during two consecutive dry years. Populations ABP 8, 3, 11 and 17 had high yields. It was confirmed that alfalfa has high ability to tolerate drought by evaluating the relationships between long-term yields of established alfalfa and total precipitation during the growing season. Populations ABP 13, 8, 3, 11 and 17 showed high yield potential and stability under drought stress and presented valuable genetic resources for our future breeding work.