Genetic Control of Leaflet Number in Soybeans1
- W. R. Fehr2
The genetic control of leaflet number in soybeans [Glycine max' (L.) Merr.] was studied using a seven-leaflet mutant (T255) found in the commercial three-leaflet cultivar ‘Hawkeye’ and a five-leaflet strain (T143) in the soybean genetic collection. The F1, F2, and F3 generations of the crosses Hawkeye ✕ T255, T143 ✕ Hawkeye, and T143 ✕ T255 were evaluated.
The seven-leaflet character was controlled by a single major gene (Lf2). Dominance of the Lf2 allele controlling trifoliolate leaves was complete in the Hawkeye ✕ T255 cross, but partial dominance was present in other genetic backgrounds. Multifoliolate leaves in T143 were controlled by a single major gene with partial dominance for the Lf1 allele controlling the five-leaflet character. There was independent assortment of the two genes controlling leaflet number. Homozygous Lf1Lf1lf2lf2 individuals with up to 15 leaflets per leaf have been observed.
Leaves of T255 with seven leaflets had a longer rachis by 8 mm and 9.4% greater leaf area than trifoliolate leaves of Hawkeye. No difference in seed yield was observed between Hawkeye and T255, indicating no yield advantage for plants with leaves with more than three leaflets.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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