Fig. 1. Pina and Pinb gene loci number in different lines at the F₃ generation determined by restriction fragment length polymorphism analysis. ‘Chinese Spring’ (CS) is homozygous at the 5D locus and has two copies. Other lines have four or six copies except lines 4 and 196, which have five copies each as they were heterozygous at the 5A locus as indicated by reduced ³²P signal and their segregation in the F₄ generation (data not shown).