MOLECULAR ASSISTED BREEDING FOR DISEASE RESISTANCE IN LILY

Abstract

The Asiatic hybrid lily (Lilium L.) 'Connecticut King' harbours several beneficial traits such as partial resistance to Fusarium and complete resistance to tulip breaking virus (TBV). The variation in resistance to Fusarium was determined in four different greenhouse tests in four different years on the same 100 descendants of a backcross population. There was considerable variation in Fusarium resistance levels over the years. TBV resistance was determined and segregated, as expected, like a monogenic trait (1:1). In order to identify quantitative trait loci (QTLs) for Fusarium resistance and also to identify linked markers to the TBV resistance a QTL mapping approach was carried out in this backcross population. Segregation of 399 polymorphic AFLPTM (amplified fragment length polymorphism) fragments was determined. Two different enzyme combinations were used, PstI/MseI and EcoRI/MseI, in the latter one extra selective nucleotide was added to the MseI primer. A paternal ('Connecticut King') linkage map was calculated. This map consisted of 24 linkage groups (Lilium 2n=2x=24) with 251 markers covering 1367 cM. About 25␘f the markers remained unlinked. Four QTLs for Fusarium resistance mapped to linkage groups 1, 5, 13 and 16 respectively. The resistance gene for TBV was placed on linkage group