Emergência e desenvolvimento inicial de porta-enxertos de citros no semiárido do Ceará, Brasil

The low diversification of combinations copa/rootstock is one of the main challenges of citrus, important economic basis. In this study we evaluated the emergence and initial development of citrus rootstocks. It was used a completely randomized design with five treatments and eight replications and plot of 25 seeds. We analyzed: T1-Rangpur lemon ‘Santa Cruz'; T2-Citrandarin 'Riverside'; T3Citrandarin 'San Diego'; T4-Citrandarin 'Indio' and T5-Mandarin 'Sunki Tropical'. The analysis was based on the percentages of emergence (PE), the 20th to the 60th day after sowing (DAS), determining the final rate of emergence (TFE) and final rate of polyembryony (TFP), calculating the emergence speed index (ESI). Held biometrics at 30, 60 and 90 of, registering height (h), diameter of seedlings (d) and stem diameter (d). The data obtained were subjected to analysis of variance, using the Tukey test (p < 0,05). The treatments T5, T2 and T3 showed a more prompt and uniformity in the initial development, differing significantly for the variables of emergency. The citrandarin 'San Diego' presented TFE exceeding 90%, ESI = 11,51, h = 18 cm, d = 75,4 mm and d2 = 2,4 mm, and we recommend its adoption in the production of seedlings of citrus rootstocks. The Rangpur lemon ‘Santa Cruz' showed the lowest performance for all variables analyzed, attributing the low moisture content in the seed.