RESISTANCE TO CLADOSPORIUM FULVUM CKE. OBTAINED FROM WILD SPECIES OF TOMATO

Abstract

In the last 20 years several varieties and breeding lines of tomato have been developed which possess immunity from C. fulvum races 1 to 9. Vagabond, Vinequeen, and V548 obtained their immunity from L. hirsutum Humb. and Bonpl.; V501 from L. hirsutum var. glabralum Muller; V542, Vantage, Waltham Mold Proof Forcing No. 22, etc. from L. peruvianum (L.) Mill.; and V545 from L. pimpinellifolium (Jusl.) Mill. Studies are reported herein on the genetic bases of resistance in these varieties.Single genes for immunity from C. fulvum race 6 were isolated in these varieties and breeding lines. Crosses between the varieties indicated that the immunity from all of these sources is conditioned by the same gene or by genes that are very closely linked. Differential races must be found before this point can be determined with certainty. The gene from L. hirsutum which confers immunity to race 6 in Vinequeen is designated as Cf4. Cf4has been shown to be located on chromosome 1, probably near Cf1.L. hirsutum, L. pimpinellifolium, and L. esculentum var. cerasiforme Mill. among them have several other genes conferring a lower level of resistance to race 6.