THE RESISTANCE BREEDING FOR IMI AND SU HERBICIDES FOR WEED AND BROOMRAPE PARASITE CONTROL IN SUNFLOWER PRODUCTION Goksel Evci 1 , Veli Pekcan 1 , M. Ibrahim Yilmaz 1 , Yalcin Kaya 1 ¹ Trakya Agricultural Research Institute, PO Box: 16, 22100 Edirne, TURKEY, Phone: +90 284 2358182, Fax:+90 284 2358210, e-mail: yalcinkaya@ttae.gov.tr ABSTRACT Weed control and broomrape (Orobanche cernua Loeffl.) are the main problems in sunflower production in Turkey. CLEARFIELD® System has been used successfully by farmers since 2003 and Imidazolinone (IMI) resistant hybrids reached about 25% of sunflower planting areas. On the other hand, sunflower hybrids resistant to Sulfonylurea (SU) herbicides are also used widely especially non broomrape problem areas in the world. Sunflower inbred lines resistant to IMI and SU herbicides were obtained utilizing mostly backcrossing method and inbreeding methods in breeding nursery of National Sunflower Project conducted by Trakya Agricultural Research Institute (TARI), Edirne, Turkey. Many sunflower IMI and SU hybrids developed and tested in regional trials in recent years and the hybrids exhibited higher yield performance was selected. Key Words: Sunflower, Broomrape, Weed Control, IMI and SU Herbicide Resistance, INTRODUCTION Sunflower is growing mainly (75%) in Trakya Region which is European part of Turkey. The 80% of region is infested by new virulent races of broomrape. CLEARFIELD system is commonly in this region due to efficient control both broomrape and key weeds in sunflower (Malidza et al., 2003; Kaya et al., 2004). While SU resistance control by one dominant gene, IMI resistance control by two genes with additive gene effects but both side dominant in the parents increase resistance level to herbicide. Mostly USDA IMI genes which transferred to cultural one utilizing backcrossing are using commonly in sunflower programs in the world (Bruniard and Miller, 2001). On the other hand, SU herbicide resistant hybrids also developed in TARI program but they are not preferred by farmers due to less efficient control over broomrape and also key weeds such as Xanthium, Cirsium, etc. in sunflower production. Research was covered of breeding works to develop IMI and SU type inbred lines and hybrids in National Sunflower Project in Edirne, Turkey in between 2004-2011. MATERIAL AND METHODS The research was conducted in TARI fields between 2004 and 2011 to develop IMI and SU inbred lines and hybrids. After getting the IMI and SU herbicide resistant public lines from USDA in 2003 and they were multiplied in first year (Al-Khatib and Miller, 2000; Miller and Al-Khatib, 2004). Then, they started to cross institute lines firstly to convert them as IMI and SU resistant ones in 2004. Sunflower has about 120-150 days growing season normally. Therefore, in summer season, plants were planted in April and harvested at September in each year. In winter seasons, plants were planted in October in growth chamber and harvested in January. IMI herbicides (Imazamox + Imazapyr (33+15 g/l)) and SU herbicide (Chlorsulfuron 75%) in both programs with double dose applied at 6-8 leaves stage in the research to abstain any problem in sunflower production. Phytotoxicity observations performed at first and 2 nd week after application each breeding stage. Broomrape resistant and IMI and SU resistant hybrids were existed as control in the research. RESULTS AND DISCUSSIONS The breeding process altered in growth chamber at winter and institute fields at summer to get two generations per year. Breeding studies of IMI and SU inbred lines were given Figure 1-4.