Breeding apple to enviromental stresses

Jabuka (Malus x domestica Borkh.) je danas najvažnija voćna vrsta umjerenog klimatskog pojasa. Važnost genetske varijabilnosti unutar roda Malus kod oplemenjivanja je postojanje gena otpornosti u raznim divljim srodnicima jabuke. Konvencionalni i monosortni uzgoj uzrokuje lakše stvaranje novih rasa patogena, a povećava se i rezistentnost štetnika na insekticide. Nove otporne sorte jabuka posjeduju gene otpornosti na ekonomski najvažnije bolesti i štetnike kao što su: fuzikladij, pepelnica, bakterijska palež i biljne uši. Oplemenjivanje podloga usmjereno je na unošenje otpornih gena prema uzročniku bakterijske paleži i raku korjenovog vrata. Otpornost jabuke na mrazove i niske temperature omogućuje sigurniju proizvodnju u ekstremnim temperaturnim uvjetima Najčešća metoda hibridizacije kojom se stvaraju otporne sorte je povratno križanje. Pirimidizacijom gena unosi se veći broj major gena otpornosti i poligenetske otpornosti na bolesti i štetnike. Upotrebom molekularnih markera omogućuje se uspješnija selekcija potomstava i odabir roditelja.Nowadays, the apple (Malus x domestica Borkh.) is the most important fruit species of temperate climate zone. The importance of genetic variability within the genus Malus at breeding is presence of resistance genes in a variety of wild apples relatives. Conventional and monovarietal cultivation can easily create new races of the pathogen, and increase the resistance of pests to insecticides. New resistant apple varieties posses genes for resistance to economically important diseases and pests such as scab, powdery mildew, bacterial blight and aphids. Breeding rootstocks is focused on the introduction of resistant genes to fire blight and crown rot. Apple resistance to frosts and low temperatures allows safer production in extreme temperature conditions. The most common method of hybridization that create resistant varieties is a back crossing. A higher number of major resistance genes and polygenic resistance to disease and pests is introduced with gene pyramiding. Using molecular markers allows the successful selection of progeny and parental choice