THE DIFFICULTYS IN OBTAINING OROBANCHE CUMANA SUNFLOWER RESISTANCE HYBRIDS

Abstract

One of the biggest issues when developing performant sunflower hybrids is broomrape, representing up to 80% of yield losses for the susceptible hybrids. The best way to eliminate the threat of Orobanche cumana in the field is to include in the breading programs the  introgression of  resistance genes in to the sunflower lines but lately it has become more and more difficult because the interaction of the female line with the genes form the restore line must fit perfectly in order to have a complete resistance to the paraziste, this aspect is couse by the very fast development of this parasite and a rapid appearance of new and more virulent races. The gene-for-gene model and different other authors agreed with monogenic and dominant inheritance of resistance to sunflower broomrape, but there are also reported  two dominant genes, one recessive gene, double dominant epistasis and dominant-recessive epistasis, coming with a concludent conclusion that resistance  must be incorporated into both parental lines for developing resistant hybrid. Since the year 2013 when we began our breading program where we develop sunflower lines and tested them to 0robanche.cumana in 5 different location in Romania  and also 1 location in Bulgaria and 1 in Spain. The purpose of the scientific paper is to to present some strategic conclusion from our testing along this 5 year of our sunflower breeding program.