One spontaneous dwarf mutant of lettuce was found in the segregating population derived from the cross 86-197-2-1-4 × Prizehead. This mutant has shrunken, dark red cotyledons and very short hypocotyls. The stems and leaves were very soft and weak. Th...
One spontaneous dwarf mutant of lettuce was found in the segregating population derived from the cross 86-197-2-1-4 × Prizehead. This mutant has shrunken, dark red cotyledons and very short hypocotyls. The stems and leaves were very soft and weak. The leaf size was smaller than 1/2 of that of the normal plant, and the flower stem was much shorter. The mutant was crossed with normal lettuce lines of 87-25M-2M and D24. The F₁ plants were normal, and the F₂ populations segregated in a 3:1 of normal and dwarf, showing that this dwarf characteristic is controlled by a single recessive gene. The results from the F₃ families confirmed the F₂ results, and the gene was named dwarf-5. The correlations of dwarf character between true second leaf length and width, number of internodes on cauline stem, three internodes length, the largest leaf length, width, and area were investigated. Dwarfing type plants could be found easily by selecting the plants having short second leaf at seedling stage.