SUMMARY

Wild Helianthus annuus naturalized in Argentina could be a valuable germplasm source for cultivated sunflower. Five wild populations collected in different environments and with different phenotype expression were evaluated as a genetic resource in a common garden study. The populations showed nor-mal meiosis and produced a good seed set when their plants pollinated the male-sterile inbred line A09 (cms PET1). The wild populations restored more than 80 % fertility of the HA89 (cms PET1) and A10 (cms PET1) inbred lines in the F1 generation. The fertility of one male sterile source from Mendoza was restored (>95%) by the maintainer line B10. The fatty acid composition differ-entiated a population from Entre Ríos with a high saturated fatty acid content (>107 g kg-1). Another population from La Pampa showed a high level (>50%) of resistance to the Sunflower Chlorotic Mottle Virus (SuCMoV). No wild popu-lations showed tolerance to imazaphyr sprayed at 2 × doses (×=80 g i.a. ha-1). A population collected in the coolest environment showed high tolerance to low temperature (15/5°C, neutral day) in the initial grow stages (<3 expande