ABSTRACT Aiming at contributing to the knowledge of the biology and propagation of Cariniana pyriformis Miers, a native species with high timber and ecological attributes, ripe fruits were harvested. Initially, in 400 seeds and 320 fruits, the size, fresh mass, seed water content, number of seeds per fruit, number of seeds per kilogram and fruit color were assessed. Then, a homogenous seed sample was immersed for 24 hours in five doses (0, 250, 500, 750 and 1000 mg.L-1) of gibberellins (GA3) and cultivated in a greenhouse. For this, a completely randomized design was adopted with six replications of 25 seeds each. Fruits and seeds showed values, on average ± standard deviation, of 76.1 ± 11 mm and 48.1 ± 8.2 mm in length, and 49.6 ± 5 mm and 7.2 ± 0.7 mm of width, respectively, with 62.3 ± 22.3 g of fresh mass per fruit and 13 ± 3.1 seeds per fruit. One kilogram corresponded on average to 6715 seeds with 11% water content. In the greenhouse, emergence speed index and emergency percentage of seedlings increased as the GA3 dose increased, allowing a more concentrated emergency process in a shorter period. Highest variation was found for fresh mass per fruit (CV= 35%) and number of seeds per fruit (CV= 24%). Immersion in 1000 mg.L-1 in GA3 for 24 hours triggers seedling emergency in C. pyriformis (approx. 71%), and then it is recommended for plant propagation, since the treatment accelerated and synchronized seedling emergency.

RESUMO A propagação por estaquia é uma alternativa para a obtenção de porta-enxertos de citros. A aplicação exógena de ácido indolbutírico (AIB), época de coleta das estacas e genótipos utilizados exercem efeito sobre o enraizamento e desenvolvimento de estacas de porta-enxertos de citros. Para estudar o efeito desses fatores, dois experimentos foram realizados. No primeiro, estacas semilenhosas dos híbridos de tangerineira 'Sunki' H49 e H77 foram coletadas no outono e final da primavera de 2013, sendo tratadas com AIB (0 mg L-1, 1.500 mg L-1 e 3.000 mg L-1). Em cada época de coleta, utilizou-se o esquema fatorial 2 x 3 (dois genótipos x três concentrações de AIB), sob delineamento em blocos casualizados. No segundo experimento, avaliou-se o desenvolvimento das estacas que enraizaram na primavera, até atingirem o ponto de enxertia. Neste caso, adotou-se o delineamento experimental inteiramente casualizado, com os híbridos H49 e H77. Os tratamentos com AIB influenciaram positivamente no enraizamento e número de raízes somente na coleta de outono, alcançando índice máximo de 23,3 % de estacas enraizadas. Na coleta do final da primavera, o enraizamento ficou próximo a 100 %, sendo desnecessário o uso de AIB. Cerca de 50 % das estacas dos híbridos de tangerineira 'Sunki' atingiram o ponto de enxertia 14 meses após a estaquia.

ABSTRACT Propagation by cuttings is an alternative for obtaining citrus rootstocks. The exogenous application of indolebutyric acid (IBA), cutting collection season and genotypes used may affect the rooting and vegetative growth of citrus rootstocks cuttings. Two experiments were conducted to study the influence of these factors. In the first one, semi-hardwood cuttings from the 'Sunki' mandarin hybrids H49 and H77 were collected in the fall and late spring of 2013 and treated with IBA (0 mg L-1, 1,500 mg L-1 and 3,000 mg L-1). For each collection season, a 2 x 3 (two genotypes x three IBA concentrations) factorial scheme was adopted, in a randomized blocks design. In the second experiment, the development of cuttings that rooted in the late spring was evaluated until grafting. In this case, a completely randomized experimental design was adopted, with the hybrids H49 and H77. The IBA treatments positively influenced rooting and number of roots only in the fall collection, peaking at 23.3 % of rooted cuttings. In the late spring collection, rooting was close to 100 %, with the IBA treatment being unnecessary. Around 50 % of cuttings from the 'Sunki' mandarin hybrids were ready for grafting at 14 months after cutting.

ABSTRACT Citrus rootstocks are obtained from seeds, selecting the apomitic seedlings. However, there is risk of not making the correct selection, due to low level of polyembryony and high heterozygosity in some species or cultivars, such as ‘Sunki’ mandarin. Therefore, obtaining the citrus rootstocks through cuttings may solve the problem. The objective of this study was to evaluate the potential of rooting semi-hardwood cuttings of ‘Sunki’ mandarin (Citrus sunki Hort. ex Tan), collected from mother plants cultivated on the field or in a greenhouse, using different concentrations of indolbutyric acid (IBA). Cuttings were collected in late spring and maintained for 90 days under greenhouse mist system. Completely randomized block design was used, with four replications in a factorial 2 x 4, concerning to two culture conditions (mother plants cultivated on the field and in a greenhouse) and four concentrations of IBA (0, 750, 1.500 and 3.000 mg L-1). The rooting of ‘Sunki’ mandarin was high, reaching 96% in both conditions of culture. The sprouting (53%) and survival (95%) of the cuttings showed satisfactory values, regardless of the IBA. The use of IBA is only necessary in cuttings originated from plants kept in greenhouse, improving rooting and number of roots.

RESUMEN Los patrones se obtienen tradicionalmente en la citricultura a partir de semillas, seleccionándose las plantas de origen apomíctica. Sin embargo, hay riesgo de no realizarse la selección correcta, debido a la baja apomixis y la alta heterocigocidad en algunas especies o cultivares, como el mandarino ‘Sunki’. La obtención de los mismos por estaquillas solucionaría el problema. El objetivo de este trabajo fue evaluar el potencial de enraizamiento de estaquillas del mandarino ‘Sunki’ (Citrus sunki Hort. ex Tan.), colectadas de matrices cultivadas en el campo o en ambiente protegido, utilizándose diferentes concentraciones del ácido indolbutírico (AIB). Las estaquillas se colectaron en el final de la primavera y se mantuvieron por 90 días en cámara de nebulización intermitente. Se adoptó el diseño experimental de bloques completos al azar, con cuatro repeticiones, en arreglo factorial 2 x 4, referente a dos condiciones de cultivo (matrices cultivadas en campo y en ambiente protegido) y cuatro concentraciones del AIB (0, 750, 1.500 y 3.000 mg L-1). El enraizamiento del mandarino ‘Sunki’ fue elevado, alcanzando el 96% en las dos condiciones. La brotación (54%) y la supervivencia (95%) de las estacas presentaron valores satisfactorios, independientemente del AIB. El empleo del AIB solamente es necesario en estacas provenientes de plantas mantenidas en el ambiente protegido, puesto que mejora su enraizamiento y el número de raíces.