Effect of plant growth regulators on flowering synchrony and hybridization efficiency in pigeon pea

Abstract:

While pigeon pea breeders can identify promising parent combinations on paper, the success of actual crosses hinges on whether both parents flower at the same time—and they often don’t. This research examined the effect of gibberellic acid (GA₃), naphthalene acetic acid (NAA), and ethrel on flowering synchrony and hybridization efficiency in three pigeon pea cross combinations at Universitas Pertanian Nusantara, Bogor, Indonesia, during kharif 2022 and 2023. Eight PGR treatments plus an untreated control were tested in a randomized block design with three replications. GA₃ + NAA combination (100 + 25 mg L⁻¹) advanced flowering in the late parent by 21 days and achieved the highest flowering synchrony index (91.3%). Hybridization success rate reached 42.1% in the GA₃+NAA treatment versus 12.4% in the control. Ethrel at 400 mg L⁻¹ was the best single-PGR treatment, with 34.8% success. Pod set per cross ranged from 1.6 (control) to 4.3 (GA₃+NAA). These results demonstrate that PGR-mediated flowering manipulation can more than triple hybridization efficiency in pigeon pea.