Morphological characteristic variation of eleven provenances of Moringa oleifera seedlings grown in the Northern Sudanese area of Burkina Faso

This research investigated the morphological characteristic variation among West African provenances of Moringa oleifera in order to select the most suitable provenance for planting in Burkina Faso. A provenance experiment involving seven provenances from Burkina Faso, one from Mali, one Ivory Coast and one from Ghana was established in June 2014 in a randomized complete block design with three replications at Ouagadougou in the North Sudanese area of Burkina Faso. Plant growth traits (height, number of branches and pinnae, leaf length and width) and biomass production (above and underground biomass dry weight, under: aboveground ratio and total dry weight) were measured on two-week old and two-month old seedlings. The result indicates no significant correlation between morphological characteristics and agroclimatic data (longitude, altitude and annual rainfall) of the seed origin. Significant variations between provenances for morphological characteristics and biomass production (P ≤ 0.05) were observed. Two-month old M. oleifera exhibited significant differences between provenances (P ≤ 0.05). The average height ranged from 107-40 cm, number of branches from 15-8, number of pinnae per leaf from 12-5, leaf length from 44-16 cm and leaves width from 105-34 cm. The aboveground biomass productions ranged from 1-14 g, underground biomass production from 1-7 g, ratio of under: aboveground from 0.4-0.9 and total dry weight from 2-21 g. Five provenances from Burkina Faso (Gaoua and Dano in the South Sudanese area, Ouagadougou, Fada N’Gourma and CNSF in the North Sudanese area) and one from Ivory Coast (Niangon-Lokoua/Abidjan) in the sub equatorial area) showed superior performances. They can be recommended for planting in Ouagadougou and other areas with similar ecological conditions.


INTRODUCTION
Moringa (Moringa oleifera Lam.) in the family Moringaceae is a plant indigenous to the sub-Himalayan regions in Northwestern India currently found in numerous countries situated in the tropical and *Corresponding author.E-mail: dao.ebou@gmail.com.Tel: +22670266509.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License sub-tropical regions across Africa, South East Asia and South America (Paliwal et al., 2011;Leone et al., 2015); where it is commonly used for animal forage, nutrition, medicine and water purification oil (Manh et al., 2005;Rashid et al., 2008).It is a fast growing, small to medium sized tree ranging between 5 and 12 m in height and tree canopy has an umbrella shaped crown with bi-(tri-)pinnate leaves, while the individual leaflets have a leaf area of one to two cm 2 (Muhl et al., 2011).Flowers are white to cream colored and zygomorphic.The tree bears 20 to 30 cm long fruit that once mature, change colour from green to brown revealing numerous round or triangular seeds with three papery wings (Arbonnier, 2002).
In West Africa, moringa leaves are mixed with other vegetables to make sauce.The use of the fresh and dried leaves as staple foods is very common in Burkina Faso.Leaves contain high amounts of total phenols and proteins and are a good source of vitamins and minerals: perhaps more than any other tropical vegetable (Ferreira et al., 2008).Moringa is used in many African feeding programs to fight malnutrition and its associated diseases, including blindness (Mulh et al., 2011).Fragrant flowers of moringa are also used as a source of vegetables and bee forage; twigs with leaves as fodder; green leaves as mulch and solid wood as energy source (Smith and Eyzaguirre, 2007).
Moringa is cultivated in tropical and sub-tropical areas with annual rainfall varying from less than 100 to over 1500 mm and different soils types (Nouman et al., 2012).It has been introduced into gardening systems because of its versatility (Palada and Chang, 2003;Nduwayezu et al., 2007).
Although moringa is grown throughout numerous agro systems, no large-scale commercial plantings have been reported, possibly as a result of the limited scientific data that is currently available on the morphological characteristics that control its survival and productivity.Therefore, further insights into the morphological characteristics of this species are needed before recommending its large scale introduction to home gardens of smallholders' growers (Scott and Sullivan, 2007).At present, data are not available to make reliable recommendations to garden landowners on the best seed sources and how the species might perform in various agroforestry systems.Therefore, the objective of this study was to evaluate the variations in morphological characteristics of the growth of M. oleifera at nursery stage for selection of seed sources suitable for plantation establishment under different geoclimatic environmental conditions.

Study site
The study was conducted at the women gardening center "Amicale des Forestières du Burkina Faso (AMIFOB)" located at Ouagadougou, Burkina Faso (12°7'32''N, 01°40'24''W).The rainfall is uni-modal with a mean annual rainfall of the last 15 years data from the nearest meteorological station in Ouagadougou, of 950 mm year -1 , with the mean potential evapotranspiration of 177 mm.month -1 and the mean temperature of 29.2°C month -1 (Figure 1a  and b).Soils are sandy clay to clay-sandy ferruginous leached with very low nutrient content according to French soil classification (Pallo et al., 2009).The common natural vegetation found at Ouagadougou is described as semi-deciduous open woodland.Main genera include, Eucalyptus, Azadirachta, Mangifera, Vitellaria, Lannea, Piliostigma, Acacia., Ziziphus, Tamarindus and Combretum.

Seed sources, experimental design and establishment
The experiment included eleven Moringa oleifera provenances of Ouahigouya (P1), Ségou (P2), Centre National de Semences Forestières (CNSF) (P3), Ouagadougou (P4), Koudougou (P5), Fada N'Gourma (P6), Bobo Dioulasso (P7), Dano (P8), Gaoua (P9), Tamalé (P10) and Niangon-Lokoua (P11) (Table 1).These provenances were selected from four countries, Burkina Faso, Mali, Ghana, and Ivory Coast and four climate areas according to their agro-ecological characteristics (Sahelian, Sub Equatorial, South and North Sudan).Seeds were collected in 2014 in plantation farmland from at least 12 mother trees per provenance.The experimental design was a randomized complete block design (RCBD) with three replications, and each plot represented a provenance planted at 5 x 6 rows in a contiguous arrangement of 20 x 20 cm (Figure 2).Plot measured 10 x 1 m and contained 30 trees and the distances between blocks were 2 m.Seed samples were pretreated with water for 24 h and sown in June 1 st 2014.Weeding was done twice during the rainy season.The seedlings were grown without fertilizers and pesticide.

Morphological measurements
The morphological measurements were performed on two-week and two-month old M. oleifera.Twenty seedlings from each provenance per block were selected randomly and their heights were assessed from root collar up to the terminal shoot using a measuring tape.At the age of two months, 20 randomly selected plants from each provenance in each block were labeled for counting the total number of branches per plant and pinnae per leaf.

Dry matter production
After two months from germination, all trees were harvested for dry matter measurements using an analytical balance.Each was separated into aboveground biomass (leaves, buds and stems) and underground biomass (roots), and dried at 70°C for 48 h using an oven.

Data analysis
All statistical analysis were carried out using ANOVA performed with JMP® Pro 11.1.1(SAS Institute, Cary, NC, USA).Normality and homoscedasticity were graphically verified on residual plots of the linear models (Quinn and Keough, 2002).When effects were significant, the Duncan test was used for multiple mean comparisons to detect the significant differences between the
There was no correlation between the altitude, longitude and average rainfall of the seed source origin with the morphological traits (leaf length and width, number of pinnae per leaf and number of branches per tree) (Figures 5, 6 and 7).

Dry matter productions
The provenances displayed substantial variations (P ≤ 0.05) in dry matter production and location (Table 2).Aboveground biomass dry weight of the provenances varied between 1.2 and 14.0 g.The provenance P9 produced the highest aboveground biomass dry weight, which was significantly different from the other provenances.The provenances P1, P2, P7 and P10 produced the smallest aboveground biomass dry weight.The underground biomass dry weight of the provenances varied from 1.0 to 7.4 g.The provenance P9 had the highest underground biomass dry weight, which was not significantly different from that produced by P3, P4, P5 and P6.However, significant difference appeared when they were compared with P1, P2 P7, P8 and P10, which produced the smallest underground biomass dry weight (Table 2).The underground biomass : aboveground ratio of the provenances varied from 0.4 to 0.9, and the highest ratio was shown by P10, but it was only significantly different from that of P1 and P8 (Table 2).Provenance P9 was also superior in total dry weight, which was significantly greater than the total dry weights produced by P1, P2, P5, P7, P8, P10 and P11 (Table 2).

DISCUSSION
This study evaluates the variations in morphological characteristics of the growth of 11 provenances of M. oleifera from different geoclimatic conditions of West Africa in order to select the seed sources suitable for plantation establishment under North Sudanese environmental conditions in Burkina Faso.Considering together all morphological characteristics and the biomass production, six provenances showed significant differences.The significant variability in the morphological characteristics was supported by previous studies on M. oleifera (Nduwayezu et al., 2007;Edward et al., 2014) and other species (Kozlowski and PaIlardy, 1997;Ky-Dembele et al., 2014).The number of pairs of pinnae (5-12) is within the range reported by Arbonnier (2002).Moreover, the variation in number of branches may be related to genetic differences (Wright, 1976).
Despite the wide geoclimatic range of the sites sources, no correlation was found between provenances and the altitude, longitude and the annual rainfall for seedlings morphological characteristics.Thus, variations in seedling morphological traits among provenances cannot be explained by the average annual rainfall, altitude and longitude at the seed source origin.These results disagree with previous works reported by Abrams (1994), who showed the relationships between high rainfall areas and the plant morphological characteristics.The significant differences in biomass production among the different parts of the provenances are consistent with the findings by Kundu and Tigerstedt (1998) in Azadirachta indica and Hardiyanto et al. (2004) in A. mangium.The good performance in above and underground biomass production of the provenances Gaoua (P9), Fada N'Gourma (P6), Ouagadougou (P4) and CNSF (P3) was attributed to its advantages in good growth in height, number of branches, pinnae and leaves at the study site.
The  strong variations in seedling morphological characteristics and biomass production among the studied provenances.
The climatic conditions prevailing in the seeds origins had no effect on the seedling's morphology and biomass production.The absence of significant correlations between the wide range of provenances from diverse geoclimatic conditions and the morphological traits and biomass production of M. oleifera was attributed to the ability of the species to grow on a wide variety of climate and soil types.

Figure 1 .
Figure 1.Mean rainfall of 2013 and 2014 (mm) (a); mean rainfall (mm), mean PET (mm) and mean temperature (°C) of the last 30 years (b) of Ouagadougou, the nearest meteorological station to AMIFOB site, Burkina Faso.

Figure 2 .
Figure 2. Moringa oleifera trial in the women gardening center of AMIFOB, a = two-week old seedlings plants; b = two-month old plants; Ouagadougou.Photo MCE DAO, Ouagadougou, 2014.

Figure 3 .
Figure 3. Morphological characteristics of M. oleifera: Average height of two weeks, and two months of age (a); average branch number of two weeks and two months of age (b).Values are means ± standard error.

Figure 5 .Figure 6 .Figure 7 .
Figure 5. Correlation of altitude with leaf length average (a), leaf width average (b), average number of branches of two-weeks old plants (c), average number of branches of two-months old plants (d) and average number of pinnae per leaf (e) of eleven provenances of M. oleifera.

Table 1 .
Seeds origin of provenances of M. oleifera used in the study.
*: This notation sequence was considered the correct one for all the manuscript.

Table 2 .
and underground biomass of two-month old plants of M. oleifera from eleven provenances (the provenance codes indicated here is in accordance with the codes in Table1modified.Values are means ± standard error.Means in the same column with the same letter (s) are not significantly different at P ≤ 0.05, according to Duncan multiple range test.