Survival , growth and biomass production of Moringa oleifera provenances at Gairo inland plateau and Ruvu Coastal Region in Tanzania

Survival, growth and biomass production was studied among 14 Moringa oleifera provenances at Gairo inland plateau-Morogoro, and Ruvu Coastal Region in Tanzania employing randomized complete block design with three replications. Growth assessment was done at six months intervals while biomass assessment was only done at 30 months. During final assessment, untransformed survival at Gairo site ranged from 65.33% for Chikwawa/Domasi (Malawi) to 98.67% for Ihumwa (Tanzania) while at Ruvu site, it ranged from 92% for PKM 2 (India) to 100% for Chikwawa/Domasi (Malawi), Mahalapye (Botswana) and Mbololo 472-029/03 (Kenya) provenances. Height ranged from 2.66 m for Makhanga (Malawi) to 5.04 m for Maun (Botswana) at Gairo site and from 4.82 m for Makhanga (Malawi) to 8.16 m for Maun (Botswana) at Ruvu site. Breast height diameter ranged from 2.80 cm for Makhanga (Malawi) to 6.07 cm for Mahalapye (Botswana) at Gairo site and from 5.18 cm for PKM 3 (India) to 8.58 cm for Maun (Botswana) at Ruvu site. Provenances Mahalapye and Maun (Botswana), Ihumwa (Tanzania), Mbololo 472-029/03 (Kenya) and PKM 1 (India) at Gairo site and Maun and Mahalapye (Botswana), Mbololo 472-029/03 (Kenya) and Ihumwa (Tanzania) at Ruvu site are recommended for planting at these and similar sites.


INTRODUCTION
Moringa is the only genus in the family Moringaceae.This genus comprises 13 species, all of which are trees that grow in tropical and sub-tropical climates.Moringa is drought resistant and can be grown in a wide variety of poor soils, even barren ground, with soil pH between 4.5 and 9.0.The most popular species is Moringa oleifera, a multi-purpose tree originally from India and now found in most tropical countries (Africa, Asia and America).Some records indicate that the species is native to the sub-Himalayan tracts of India, Pakistan, Bangladesh and Afghanistan (Fahey, 2005).Fahey (2005) further indica-ted that the tree species is locally known by many names like horseradish tree, drumstick tree, benzolive tree, kelor, marango, mlonge, moonga, mulangay, nébéday, saijhan, sajna or ben oil tree.The species is easy to reproduce and its growth is very fast that have raised growing international interest due to its social, economic and environmental importance which can benefit humans and animals nutritionally, economically and as an energy source.
Moringa is an important food source in many countries.In India, Moringa pods are widely consumed and *Corresponding author.E-mail: mathewmndolwa@yahoo.com.Plantations exist to produce pods for export, fresh and tinned, to overseas consumers.In West Africa, Moringa oleifera leaves are commonly used to make sauces.Moringa stenopetala leaves are the staple food of the Konso people in Ethiopia.Studies have shown M. oleifera leaves to be an excellent source of vitamins, minerals and protein: perhaps more than any other tropical vegetable.Many programmes use Moringa leaves to fight against malnutrition and its associated diseases including blindness.Fragrant/tender flowers of Moringa are also used as a source of vegetables and bee forage (Mbuya et al., 1994), twigs with leaves as fodder, green leaves as mulch and solid wood as energy source (FAO, 1988;Morton, 1991;D'Souza and Kulkarmi, 1993).Moringa seeds contain a cationic polyelectrolyte that has proved efficient in water treatment, as a substitute to aluminium sulphate and other flocculents (Evans, 1991;Mayer and Stelz, 1993;Olayemi and Alabi, 1994;Folkard and Sutherland, 1996).Oil extracted from the seeds is an excellent edible vegetable oil and is also useful in the cosmetics industry.The press cake left after oil extraction from the seeds can be used as a soil conditioner or as fertilizer and forage, it has the potential use as protein supplement for livestock (ruminants) (Sá nchez et al., 2006) and poultry (Evans, 1991;Olayemi and Alabi, 1994;Folkard and Sutherland, 1996).
Although M. Oleifera is wide spread in many African countries its original sources is unknown (Jahn, 1988a, b, c;Folkard and Sutherland, 1996;Panga, 2002).The material therefore, is most likely of narrow genetic base.Also, the knowledge about genetic improvement and proper management of this valuable multipurpose tree species is limited.Given dangers of planting materials based on a narrow genetic base, there is a need to evaluate different provenances of this species with a view of identifying the provenances that maximize productivity Edward et al. 55 in various parts of Tanzania.In addition to increasing wood biomass productivity, pod, seed and leaf quality, broadening the genetic base will serve as an insurance against pests, diseases and climatic fluctuations.This study therefore evaluated M. oleifera provenances in terms of survival, height, diameter growth and biomass production.

The study sites
The study was carried out at two contrasting sites: Gairo and Ruvu sites with established replicate trials in each.Gairo site is located in Gairo District, Morogoro Region (36° 45' E; 6° 0° S; 1 300 m a. s. l.) along the Morogoro-Dodoma highway about 130 km from Morogoro town and 140 km from Dodoma.Rainfall is poorly distributed, and varies from year to year.The average annual rainfall is around 499 mm, most of which falls between November and May (Herbert et al., 2002).The geology of the site is Usagaran system.The soil is generally classified as Haplic Lixisols (Msanya and Msaky, 1994).
The soil properties of the study site are as described by Mugasha et al. (2000).The soil has low inherent fertility.The soil texture is sandy clay loam with pH in the upper 50 cm soil depth varying from 6.1-6.3, total nitrogen 0.11-0.16%and Bray I available phosphorus 0.18-3.38ug/g.The natural vegetation found around the site consists mainly of shrubs and few scattered miombo tree species.Ruvu site is located at Kibaha District, Coast Region (6° 33' -6° 43'; 38° 48' S -39v 03' E) some 60 km from Dar-es-Salaam city along Dar-es-Salaam -Morogoro highway.It is within low elevations some 80 m a. s. l.The area has mean rainfall of 900 mm per annum falling in average of 81 days (Maghembe, 1979) with irregular pattern.Heavy rains fall between March and May and light rains between November -December.Temperatures are always high tending to be the highest in January and on average the temperature ranges between 23 and 27°C having occasional minima as low as 18°C and maxima of 33°C.Soils vary substantially over short distances.They are free draining, primarily sandy, sandy loam and gravel.Soil pH varies with soil depth.The top 50 cm has pH predominantly ranging from 5 -6.5, increasing with increase in soil depth reaching extremes of pH 9.4 at 72 cm below surface (Holmes, 1988).The common natural vegetation found at Ruvu can be described as semi deciduous open to partly closed woodland to fairly open evergreen thicket and riverine forest.Main genera include, Pteleopsis, Strichnos, Combretum, Albizia, Brachystegia, Jubernadia, Vitex, Afzelia and Dalbergia.

Source of provenances
Fourteen (14) M. oleifera provenances were studied in each site (Table 1).Potted seedlings of the provenances were raised at Gairo and Ruvu nurseries using standard cultural techniques (Forest Division, 1982).

Experimental design
Trials were planted in a randomised complete block design (RCBD) with three replications.Each plot represented a provenance planted at 5 x 5 rows in a contiguous arrangement at an espacement of 2 x 2 m.Plots measured 8 x 8 m and contained 25 trees.Distances between blocks were 4 m.Each block had one buffer row planted at the same spacing.

Field procedures
Sites were prepared by clearing all vegetation using hand hoes followed by ploughing and pitting (pit size: 30 x 30 cm).Planting was done in January and March 2006 at Gairo and Ruvu sites respectively.Weeding was done three times during the rainy season and once during the dry season.

Data collection
Assessments were carried out at ages of 6, 12, 18, 24 and 30 months after planting.During the first assessment, survival, root collar diameter 30 cm above ground (RCD) and height (HT) were assessed while in subsequent assessments diameter at breast height (Dbh) was also measured.Biomass production was measured at final assessment.Height was measured using calibrated height measuring pole while RCD and Dbh were measured to the nearest 0.01 cm using a veneer calliper.

Data analysis
All statistical analyses were carried out using General Linear Model (GLM) of Statistical Analysis Systems (SAS) (SAS Inst. Inc., 1991).For all statistical analysis, a fixed effect model was fitted (equation 1) and a type III SS analysis was carried out.All data were subjected to analysis of variance (ANOVA) using plot means.Data for percentage survival was arcsine transformed prior to analysis to remove bias (Sokal and Rohlf, 1969).For significantly different provenance means, the Duncan's multiple range test (DMRT) was used for separating means (Gomez and Gomez, 1983) at 5% probability level.
The general linear model was denoted as: Where, Y = the measurement To identify the best and the worst overall performing provenance at final assessment, ordinal ranking was performed.This was done as follows; for each significant variable evaluated, provenances were assigned ranks from the best (assigned 1 point) to the worst (assigned 14 points) performing provenance.Thereafter, ranks were added, averaged, and the overall score was taken as a basis of the overall provenance ranking.

Survival
The results for tree survival for different M. oleifera provenances planted at Gairo and Ruvu sites are presented in Tables 2 and 3, respectively.The differences in survival were significant (P<0.05)throughout the assessment period at Gairo site while at Ruvu site provenances did not differ significantly (P>0.05).

Root collar diameter
The results of tree RCD for different M. oleifera provenances planted at Gairo and Ruvu sites are presented in Table 4. Provenances differed significantly (P<0.05) in RCD at both sites in all months of assessment.RCD ranged between 5.36 cm for Mangochi (Malawi) and 8.91 cm for Mahalapye (Botswana) at Gairo site and 7.43 cm for PKM 3 (India) and 10.67cm for Maun (Botswana) at Ruvu site during the final assessment occasion.

Diameter at breast height
The results of tree Dbh for both sites are presented in Table 5. Provenances differed significantly (P<0.05) in Dbh at both sites in all months of assessment.Dbh ranged between 2.86 cm for Makhanga (Malawi) and 6.07 cm for Mahalapye (Botswana) at Gairo site and 5.28 cm for PKM 3 (India) and 8.58 cm for Maun (Botswana) at Ruvu site during the final assessment occasion.

Height growth
Trends for height growth of M. oleifera provenances for Gairo and Ruvu sites are as shown in Table 6.Significant variation (P<0.05) in height development was observed at all assessment occasions.The mean height ranged between 2.66 m for Makhanga (Malawi) and 5.04 m for Maun (Botswana) at Gairo site and 4.82 m for Makhanga (Malawi) and 8.16 m for Maun (Botswana) at Ruvu site during the final assessment occasion (30 months after planting).
It is interesting to note that at many assessment occasions in both sites, Maun (Botswana) showed superiority in height growth even though no one single provenance maintained one rank throughout the period.Makhanga (Malawi) provenance showed poor height growth at all assessment occasions in both sites.

Biomass production
The results for stem and foliar biomass for M. oleifera provenances at Gairo and Ruvu sites are presented in Table 7. Provenances differed significantly (P<0.05) in biomass production at Gairo site during the last assessment occasion while at Ruvu site provenances did not differ significantly (P>0.05) in biomass production.Stem and foliar biomass at Gairo site ranged from 5 901.08 kg ha -1 for Mangochi (Malawi) to 24 733.60 kg ha -1 for PKM 2 (India) and 491.02 kg ha -1 for Ngabu (Malawi) to 4 407.18kg ha -1 for Maun (Botswana), respectively.At  Ruvu site stem and foliar biomass ranged from 15 796.17 kg ha -1 for Makhanga (Malawi) to 41 403.26 kg ha -1 for Mahalapye (Botswana) and 697.10 kg ha -1 for Makhanga (Malawi) to 1 917.21kg ha -1 for Maun (Botswana) respectively.

Ordinal ranking
When the ranking of provenances in six tree variables (survival, mean height, RCD, Dbh, stem biomass and foliage biomass production) was computed, provenances were ranked as shown in Tables 8 and 9 for Gairo and Ruvu sites, respectively.

Survival
General assessment at all occasions, showed good performance among provenances.All provenances in both sites except two at Gairo site had survival assessments above 80%.The significant differences in survival at Gairo site could be attributable to provenances difference in tolerance to arid/semi arid conditions of the study site (Edward et al., 2006).In this case provenances from Ihumwa (Tanzania), Mtakataka/Dedza (Malawi), Maun (Botswana), PKM 2 (India) and Jafna/Jaffana (India) appear to tolerate dry conditions than Chikwawa/-Domasi (Malawi).The excellent performance of these provenances is an indication of better adaptation to the site condition while the insignificant differences among provenances at Ruvu site implies that all provenances have adapted well in the sub-humid conditions of this site.

Root collar diameter
Significant variation (P<0.05) in RCD development was observed at all sites during the whole assessment period.At Gairo site, the study indicates the superior RCD development of Mahalapye (Botswana) and Maun (Botswana), Mbololo 472-029/03 (Kenya) and Ihumwa (Tanzania) and poor RCD development of Mangochi (Malawi) and Makhanga (Malawi).Similar results have been observed in Zimbabwe (Gadzirayi et al., 2013;Goss, 2012).At Ruvu site, the study indicates the su-perior RCD development of Maun (Botswana), Ihumwa (Tanzania), Mtakataka/Dedza (Malawi) and Mbololo 472-029/03 (Kenya) and poor RCD development of PKM 3 (India) and Honduras (Honduras).The differences in RCD development within a site could be attributed to variations in adaptability among provenances, but generally the provenances at Ruvu site showed good performance in RCD development, which is expected due to the sub-humid conditions of the site.

Diameter at breast height
Significant variation (P<0.05) in Dbh was observed on all sites during the whole assessment period.At Gairo site, the study indicates the superior Dbh development of Mahalapye (Botswana) and Maun (Botswana) and poor Dbh development of Makhanga (Malawi) and Ngabu (Malawi).These results are in agreement with those reported in Zambabwe where Mutoko provenance from Zimbabwe performed very well as compared to Malawi provenance (Gadzirayi et al., 2013).For Ruvu site, the study indicates the superior Dbh development of Maun (Botswana) and Ihumwa (Tanzania) and poor Dbh development of PKM 3 (India) and Honduras -Honduras.The differences in Dbh development could be attributed to variations in adaptability among provenances, but generally the provenances at Ruvu site showed good performance in Dbh development.Good climatic condition, that is, availability of rainfall and genetic superiority could have contributed to the good performance of these provenances at Ruvu site and those from Botswana at Gairo site.

Height growth
This study has shown superior height growth for Maun (Botswana) and Mahalapye (Botswana) provenances at Gairo site and poor height growth of Makhanga (Malawi), Ngabu (Malawi) and Mtakataka/Dedza (Malawi) provenances.At Ruvu site, only Maun (Botswana) provenance showed superior height growth while Makhanga (Malawi) and Chikwawa/Domasi (Malawi) pro-venances showed poor growth in height.The differences in height growth within a site could be attributed to variations in adaptability among provenances while the between site differences in growth relate with rainfall differences between the two sites with Ruvu having higher rainfall as compared to Gairo.Generally, the provenances showed good performance in height development at Ruvu site.The growth performance of outstanding provenances in the present study compare favourably with results reported in Song Hau State farm, Cantho City, Vietnam (Manh et al., 2005) and in Zimbabwe (Gadzirayi et al., 2013;Goss, 2012).The Vietnam site has higher annual rainfall of 1800 -2000 mm as compared to that of the study sites.

Biomass
Most provenances grown at the Ruvu site showed high production of foliar and stem biomass than those grown at Gairo site.This could be due to sufficient availability of growth resources (rainfall) at Ruvu site unlike the Gairo site.The lowest yield in stem biomass at Gairo site were recorded from Ngabu (Malawi) and Mangochi (Malawi) while at Ruvu site were recorded for Mangochi (Malawi) and Makhanga (Malawi) provenances.The lowest yield in  unacknowledged.

Table 1 .
Sources of M. oleifera provenances planted at Gairo and Ruvu sites, Tanzania.

Table 2 .
Survival and transformed survival of 6, 12, 18, 24 and 30 months old M. oleifera provenances planted at Gairo, Morogoro, Tanzania.Means of individual species/provenance with standard error in parenthesis.Means of the same letter within the same column are not significantly different.UTSv, untransformed survival; TSv, transformed survival. *
*Means of individual species/provenance with standard error in parenthesis.Means of the same letter within the same column are not significantly different.UTSv, untransformed survival; TSv, transformed survival.
*Means of individual species/provenance with standard error in parenthesis.-Means of the same letter within the same column are not significantly different.

Table 5 .
Diameter at breast height of 12, 18, 24 and 30 months old M. oleifera provenances planted at Gairo site, Morogoro and Ruvu site, Coast Region, Tanzania.Means of individual species/provenance with standard error in parenthesis.-Means of the same letter within the same column are not significantly different. *

Table 6 .
Height growth of 6, 12, 18, 24 and 30 months old M. oleifera provenances planted at Gairo site, Morogoro and Ruvu site, Coast Region, Tanzania.Means of individual species/provenance with standard error in parenthesis.-Means of the same letter within the same column are not significantly different. *

Table 7 .
Biomass production of 30 months old M. oleifera provenances planted at Gairo site, Morogoro and Ruvu site, Coast Region, Tanzania.

/ha) Foliage(Kg/ha) Stems(Kg/ha) Foliage (Kg/ha)
Means of individual species/provenance with standard error in parenthesis.Means of the same letter within the same column are not significantly different foliar biomass at Gairo site were recorded for Ngabu (Malawi) and Makhanga (Malawi) provenances while at Ruvu site were recorded at Makhanga (Malawi) and Chikwawa/Domasi (Malawi) provenances.This poor performance could probably be due to poor genetic adaptations influenced by climatic conditions in these areas. *