<p>(A) Frequency of F2 plants derived from crosses of <i>C</i>. <i>grandiflora</i> × <i>C</i>. <i>rubella</i> producing defined rates of seed abortion when backcrossed to <i>C</i>. <i>rubella</i> maternal plants. (B) Theoretical distribution of F2 plants producing defined rates of seed abortion when assuming that one maternal locus from <i>C</i>. <i>rubella</i> negatively interacts with two or three paternal loci from <i>C</i>. <i>grandiflora</i>. Experimental data correspond to data shown in (A). Significance of the observed distributions with the predictions of the models has been tested by Chi-square and P>0.05 is marked by an asterisk. Ns, non significant. (C) LOD scores for paternal <i>C</i>. <i>grandiflora</i> QTLs affecting abortion of <i>C</i>. <i>rubella</i> × <i>C</i>. <i>grandiflora</i> hybrid seeds. The purple line (top) represents the LOD score of each marker and the purple line (bottom) represents the effects. The red line represents the significance threshold as estimated by 1,000 permutations.</p
