Fine mapping of two recessive genes TaFLA1 and TaSPL8 controlling flag leaf angle in bread wheat

Flag leaf angle is one of the key target traits in high yield wheat breeding. A smaller flag leaf angle reduces shading and enables plants to grow at a higher density, which increases yield. Here we identified a mutant, , with an 84.34%–89.35% smaller flag leaf angle compared with the wild type. The mutant also had an abnormal lamina joint and no ligule or auricle. Genetic analysis indicated that the ligule was controlled by two recessive genes, which were mapped to chromosomes 2AS and 2DL. The mutant allele on chromosome 2AS was named , and it was fine mapped to a 1 Mb physical interval. The mutant allele on chr. 2DL was identified as , a novel allele of with a missense mutation in the second exon, which was used to develop a cleaved amplified polymorphic sequence marker. F and F lines derived from crosses between Jing411 and were genotyped to investigate interactions between the and alleles. Plants with the genotype had 58.41%–82.76% smaller flag leaf angles, 6.4%–24.9% shorter spikes, and a greater spikelet density (0.382 more spikelets per cm) compared with the wild type. Plants with the genotype had 52.62%–82.24% smaller flag leaf angles and no differences in plant height or spikelet density compared with the wild type. plants produced erect leaves with an abnormal lamina joint. The two alleles had dosage effects on ligule formation and flag leaf angle, but no significant effect on thousand-grain weight. The mutant alleles provide novel resources for improvement of wheat plant architecture.