Post-pollination endogenous phytohormone levels in reproductive organs in 2 interspecific Arachis crosses differing in compatibility

Abstract Wild Arachis species are of great value to the genetic improvement of the cultivated peanut; however, incompatibility hinders the utilization of the species outside section Arachis. Endogenous phytohormone imbalance was hypothesized but is yet to be confirmed. Using UPLC-ESI-MS/MS, we were able to determine the phytohormone levels in flower bases 3 days after pollination and pegs/pods 5 and 10 days after soil penetration. The results showed that as far as the significantly changed phytohormones were considered, with the advancement of reproductive development, the proportion of down-regulated auxins and cytokinins gradually increased. Significantly reduced levels of gibberellins in pegs/pods were also recorded. The study suggested that to get desirable results in overcoming incompatible obstacles in wide crosses in Arachis, early post-pollination application of hormone mixtures incorporating auxins, cytokinins and gibberellins should be beneficial.