Genotypic interrelationships for flowering traits in sugarcane genotypes treated by Gibberellic acid under natural conditions

The low flowering intensity of some sugarcane germplasm decreases seed yield. Flowering ability and intensity are desired traits for a successful sugarcane breeding program. The goal of the study was to evaluate the effects of various foliar gibberellic acid (GA3) concentrations (0, 50, and 100 mg l⁻¹) on 20 sugarcane genotypes to improve their flowering ability and intensity under natural conditions at El-Sabahia Research Station (31o 12 54″ N and 29o 58' 23″ E), Alexandria, Egypt, over the plant and ratoon cane crops grown in the 2020/2021 and 2021/2022 seasons. The results revealed that increasing GA3 concentrations up to 100 mg/l improved the flowering percentage during the various flowering stages of the 20 sugarcane genotypes. Sugarcane genotypes, namely MEX2001-80, Co1129, and CP63-49, outperformed the others during the flowering stages. The interactions between sugarcane genotypes and GA3 concentrations had a significant impact on flowering percentage. According to cluster analysis, the longest full emergence flowering period was 142.24 days, whereas the shortest period was 0.0 days. It was discovered that the Mex 2001–80 genotype's superiority in longevity was mostly due to its superiority in the emergence stage. The GT biplot's polygon view was used to identify the genotypes that showed good flowering responses for one or more GA3 concentrations. According to the study, the responsive sugarcane genotypes may be treated with 100 mg/l of GA3 to induce floral primordia, which will speed up and intensify flowering. Selection should concentrate on tip emergence stage and full emergence stage to increase flowering percentage, according to genotypic correlation. Finding the best sugarcane genotypes in natural settings is crucial, as evidenced by the necessity for additional research using higher concentrations of GA to evaluate all sugarcane germplasms for flowering ability and intensity.