SCREENING FOR FUSARIUM RESISTANCE IN SEEDLING POPULATIONS OF ASIATIC HYBRID LILY

A test to select Fusarium resistant seedlings of the Asiatic hybrid li ly is described. Young seedlings of 28 populations, obtained from an i ncomplete diallel between eight parents with different levels of Fusar ium resistance, were tested for resistance. Significant differences in Fusarium resistance between and within populations were detected. The average percentage of selected seedlings ranged from 34% in resistant x resistant crosses to 2% in susceptible x susceptible crosses. Altho ugh resistant descendants were obtained in susceptible x susceptible c rosses, using at least one resistant parent produced higher percentage s of resistant seedlings. The resistance level of the parents correlat ed highly with the general combining ability for Fusarium resistance b ased on the seedling test. For eight populations, seedlings selected f or Fusarium resistance and non-tested (control) seedlings of the same cross were compared, after propagation, in a clonal test. Variation be tween and within populations, found at seedling level, was confirmed a t clonal level. A positive selection response was found for all eight populations. In the seedling test, approximately 18% of the seedlings were selected as resistant of which 15% (2.7% of seedlings tested) app eared to be susceptible escapes. Comparison between selection at seedl ing level and at clonal level indicated that approximately 25% of the seedlings tested were missed (rejected resistant plants) in the seedli ng test. The practical use of a seedling test for Fusarium resistance in lily breeding programs is discussed.