DOMESTICATION OF ALLANBLACKIA FLORIBUNDA: VEGETATIVE PROPAGATION BY LEAFY STEM CUTTINGS IN THE NIGER DELTA REGION OF NIGERIA 1*Anegbeh, P. O., 2Tchoundjeu, Z., 3Simons, A. J. and 4Roy-Macauley, H. 1 World Agroforestry Centre (ICRAF), West and Central Africa, ICRAF Office, c/o International Institute of Tropical Agriculture (IITA), IITA Station, Onne, P.M.B. 008, Nchia-Eleme, Rivers State, Nigeria. Tel: +234 2 241 2626 Ext 2399. Fax: +234 2 241 2221. Email: [email protected] 2World Agroforestry Centre (ICRAF), West and Central Africa, Yaounde, Cameroon. 3World Agroforestry Centre (ICRAF), East and Central Africa, P. O. Box 30677, Nairobi, Kenya, 4World Agroforestry Centre (ICRAF), West and Central Africa, BP 320, Bamako, Mali. * Corresponding Author Running Title: Domestication of Allanblackia in Nigeria Anegbeh et al. ABSTRACT Allanblackia floribunda, one of the indigenous fruit tree species of West, Central, and East Africa, is in danger of extinction. In spite of its uses as livestock feed, bait to trap animals, firewood etc, the species had in the past received little attention. Information on the vegetative propagation of A. floribunda is currently unavailable in published forms. Studies were carried out at ICRAF nursery located at Onne, Rivers State, Nigeria to determine the rooting success of single node leafy stem cuttings of A. floribunda. In 2005, four fruiting female trees were selected from farmers’ fields located at Onne. The treatments consisted of softwood cuttings (re-growth) collected from three felled female trees marked as T1, T2, and T3, and hardwood cuttings collected from canopy of mature tree (control), marked as T4. The cuttings were trimmed and placed on white river sand in non-mist propagators for 11 months. Rooted cuttings were potted, gradually hardened off, allowed to initiate new growth and planted out in a gene bank. Results of the experiment demonstrated that rooting ability of A. floribunda basically depended on genotypes. Cuttings set on river sand substrate took 3 months to root. The best cultivar with the most rooting ability had over 50% rooting in 8 months. This is encouraging since seeds of A. floribunda require 8 to 12 months to achieve 0.01% germination. There was significant linear relationship between rooting percent and time in all four trees. This information is important as it helps to encourage farmers to domesticate A. floribunda. Trees 2 and 3 (T2 and T3) are recommended to farmers. Participatory tree domestication is being used in trees and market theme of ICRAF to develop A. floribunda and other fruit and medicinal trees for rural farmers in an effort to contribute to the overall nutritional well being and reduce poverty of rural communities in Africa. Keywords: Allanblackia floribunda, cuttings, Niger Delta, rooting, softwood INTRODUCTION Domesticating agroforestry trees involves accelerated and human-induced evolution to bring species into wider cultivation through farmer-driven and market-led process. Its use and adoption enable rural farmers to commercially produce improved propagules of trees, especially fruit trees. Allanblackia, named after Allan Black, 19th century key botanist is a small genus. Allanblackia floribunda Oliv is one of the nine species of the genus Allanblackia. The tree, which grows up to 30 m, is evergreen, and has a straight bole (occasionally fluted). Branches of the tree are slender and dropping and often conspicuously whorled (Keay, 1989). It belongs to the family Clusiacea. The fruit of A. floribunda, which is known as izeni and uzoka (Edo), orogbo-erin (Yoruba), egba (Ibo), ediang (Efik), obobio-obo (Ijaw), contains about 50 brittle-shelled seeds. The fruit is brown, roughly fleshy and slightly grooved longitudinally. It is often confused with Pentadesma butyracea and Garcinia kola. Ecologically, Allanblackia floribunda is found in wide range of habitats: it is distributed in wet evergreen rainforests. The tree thrives well in the Niger Delta Region of Nigeria, especially in abandoned forests (acidic soils) with rainfall as high as 2400 mm. It is also found in forest reserves, fallow lands, surrounding farmlands, etc. Continentally, Allanblackia floribunda is found in many African countries (Angola, Cameroon, Democratic Republic of Congo, Ghana, Kenya, Nigeria, Sierra Leone, and Tanzania). 2 It is a seasonal fruit and mostly found during the rainy season. It is an indigenous fruit tree that has been recognized recently as containing valuable industrial edible oil, which is used for the manufacturing of margarine, soap, chocolate, ointment and food products (cashew and pea nuts). Ethnobotanic studies on the traditional uses of Allanblackia floribunda carried out in Nigeria in 2005 clearly indicated that farmers valued Allanblackia floribunda for firewood and for making huts, doors, windows, poles, bridge-piles, yam stakes, candlesticks, chewing sticks. Local hunters use the fruits as animal feeds/bait in trapping animals such as rats and porcupines (Anegbeh et al 2005a). Cooked seeds are edible in Gabon. Kernels have 25.5% stearic acid and 46.9% oleic acid. Medicinally, the bark relieves body pain, cough, asthma, bronchitis, dysentery and tooth ache. The germination of A. floribunda seeds is problematic. Untreated seeds take 8 to 12 months to reach 0.01% germination. Seeds treated with gibberellic acid did not germinate after 7 months of testing. It appears, therefore, that alternative approaches need to be developed urgently for propagating A. floribunda. One such approach is vegetative propagation by leafy stem cuttings. But no published data are available on the vegetative propagation of A. floribunda in Nigeria. This study was conducted to determine the rooting ability of different genotypes of A. floribunda propagated by leafy stem cuttings in the Niger Delta Region of Nigeria. MATERIALS AND METHODS The study was conducted from 2005 to 2006 at ICRAF tree nursery and demonstration fields located at the International Institute of Tropical Agriculture (IITA), 3 0 0 Onne, (04 51' N Latitude 07 03' E Longitude), Rivers State. The station has annual rainfall of 2400 mm (Anegbeh et al., 2006). In 2005, superior trees with desirable traits were selected from fruit bearing trees in fallow and farmers’ fields at Onne village and marked. They were given identification numbers as T1, T2, T3, and T4. Three of the selected trees (T1, T2, and T3) were felled to obtain re-growth (coppicing). Non-mist propagators were constructed in the nursery and filled with different substrates. Cuttings of A. floribunda were collected from the selected female trees during the last quarter of the year 2005 when most of the fruits have been collected. The selected cuttings were free-from diseases and insect pests. A minimum of four hundred cuttings of A. floribunda of known identity were selected from each of the mature female parent trees and dipped in a bucket of water prior to moving into the nursery. The cuttings were prepared using standard procedure developed by ICRAF. Pair of scissors and surgical blade were used to trim the leaves of the cuttings and inserted inside the substrate, containing white river sand, in the non-mist propagators. A knapsack sprayer was used to water the cuttings. Rooting of cutting was monitored at one month interval. The treatments consisted of softwood cuttings (re-growth) collected from three genotypes of felled female trees marked as T1, T2, and T3, and hardwood cuttings collected from canopy of mature tree (control), marked as T4. The rooted cuttings were removed from the non-mist propagators when well- developed adventitious roots were observed. Harvested cuttings were potted directly inside black polyethylene bags measuring 25 x 35 x 45 cm which were filled with potting mixture (top soil, sawdust and sand) in the ratio of 3: 2: 1. They were arranged inside 4 giant humidity chambers. Watering of the cutting was done to maintain high humidity environment, between 75 and 100%, within the chambers, by applying about 10 cl of water to each plant twice daily for one week. Thereafter, watering was done once a day. The rooted cuttings were hardened for three months in a partially shaded condition (acclimatization). The rooted and weaned plants of A. floribunda were planted in field gene bank in September 2006 at 10 m x 8 m spacing (125 plants per hectare). The cuttings were replicated three times in a completely randomized design Analysis of variance (ANOVA) and regression analysis were conducted using statistical analysis system (SAS) program package (SAS 1996). RESULTS No detectable rooting was observed during the first 2 months after setting (2 MAS) the cuttings in all of the cultivars evaluated. At 3 months of setting, small percentages of rooting were obtained for T1, T2, and T3 (Fig 1). 60 50 T3 40 T4 30 (%) 20 T2 10 T1 Rooting Percentage Percentage Rooting 0 0123456789101112 Time (Months) Fig. 1. Rooting Percentage of Allanblackia floribunda cuttings in Onne (11 MAS) 5 45 40 35 y = 4.745x - 14.082 30 25 R2 = 0.94 (%) 20 15 10 5 Rooting Percentage Percentage Rooting 0 0123456789101112 Time (Months) Fig. 2. Relationship of Allanblackia floribunda rooting of T1 cuttings with Time 70 60 y = 5.0017x + 8.9994 2 50 R = 0.85 40 (%) 30 20 10 Rooting Percentage Percentage Rooting 0 0123456789101112 Time (Months) Fig. 3. Relationship of Allanblackia flribunda rooting of T2 cuttings with Time 50 40 y = 4.9x - 13.856 30 R2 = 0.91 (%) 20 10 Rooting Percentage Percentage Rooting 0 0 1 2 3 4 5 6 7 8 9 10 11 12 Time (Months) Fig. 4. Relationship of Allanblackia floribunda rooting of T3 cuttings with Time 6 16 14 12 y = 1.7217x - 8.0628 10 R2 = 0.82 8 (%) 6 4 2 Rooting Percentage Percentage Rooting 0 0123456789101112 Time (Months) Fig. 5. Relationship of Allanblackia floribunda rooting of T4 cuttings with Time There was a significant linear relationship (R2 = 0.94), (R2 = 0.85), (R2 = 0.91), and (R2 = 0.81), between rooting percent of leafy stem cuttings and time for T1, T2, T3 and T4 respectively (Figs 2-5).