Variation for aphid resistance and insecticidal acyl sugar expression among and within Lycopersicon pennellii‚Äźderived inbred backcross lines of tomato and their F1 progeny uri icon

abstract

  • Five inbred backcross lines (IBL) were selected for higher relative expression of insecticidal acyl sugars (rank average) from an inbred backcross population derived from the cross Lycopersicon esculentum cultivar 'Peto 95' x Lycopersicon pennellii accession LA 716. These five BC2S5 IBLs were crossed in a partial diallel design (Method II), and their self and F-1 progeny and three control cultivars were tested at two California field locations in 1996. Counts of potato aphids, Macrosiphum euphorbiae Thomas, on leaves, as a measure of plant infestation, revealed significant general combining ability (GCA) for lower aphid numbers with IBL44 and IBL59; the F-1 hybrid IBL44 x IBL59 had significantly fewer aphids per leaflet than the susceptible cultivar 'Alta'. GCA for acyl sugars was associated with IBL59 only. Of all the IBL and IBL x IBL F-1 hybrids, only IBL59 produced significant levels of acyl sugars. Significant within IBL59 variation for acyl sugars was observed, but not for aphid resistance. Our results suggest that factors other than acyl sugars contributed to L. pennellii-derived aphid resistance in IBL x IBL F-1 hybrids and IBL that do not produce significant amounts of acyl sugars. IBL59 and IBL44 may be useful for breeding for aphid resistance in cultivated tomato.

publication date

  • 1999
  • 1999