A note on baobab (Adansonia digitata L.) in Kordofan, Sudan

The isolated Sudanese baobab (Adansonia digitata L.) populations, located at the northernmost limit of the East African distributional range of the species, are regarded as important genetic resources. The morphological variation in fruits of selected baobab trees in Kordofan, Sudan, was evaluated by sampling fruits and assessing their characteristics. Furthermore, locations and stem diameter at breast height of 240 baobabs were mapped for a stand in Kordofan. Our preliminary results indicated a high diversity in fruit phenotypes. Ventricose, crescent-shaped, globose and fusiform fruit types were identified. Fruit shape varied between trees but was consistent within each individual tree. Percentage of fruit pulp varied between the different fruit types with 14, 15, 18, and 21 % recorded for ventricose, fusiform, crescent-shaped and globose fruits, respectively. Interesting was also the observation of baobab morphotypes that retained leaves during the dry season. Variation in leaf morphology could also be recognised. Measurements of baobab trees revealed a density of 0.72 individuals ha^?1. Stem diameters ranged from 0.06 to 4.77 m. The size class distribution (SCD) showed an inverse J-shaped curve with a SCD slope of ?0.57 which indicates a viable regenerating population. Based on the results recorded, enhancement of scientific research activities on the almost unstudied baobabs in Kordofan, Sudan is highly recommended.     

Genetic and morphological variation in breadfruit (<Emphasis Type="Italic">Artocarpus altilis</Emphasis> (Park.) Fosberg) in the Western Ghats of India using AFLP markers

Artocarpus altilis (Park.) Fosberg is an important fruit vegetable tree grown in the homesteads of southern part of India. To provide reasoned scientific management practices and conservation measures, the pattern of morphological and genetic variation were investigated for six populations using Amplified Fragment Length Polymorphism (AFLP) markers and 15 morphological traits. The use of five selective primer combinations on 60 samples resulted a total of 414 bands in which 85% were polymorphic. The values of Nei’s genetic distance varied from 0.0044 (Palai–Palghat) to 0.3376 (Palghat–Mangalore). Analysis of molecular variance revealed most of the variation within populations (57.45%) than (42.55%) among populations. The genetic variation by AFLP data is not reflected in quantitative morphological variables. However, the genetic and geographical distances were positively correlated which were further well supported by the PCO analysis and Dollo-parsimony tree, both show the tendency of the individuals to group according to the geographical localities.     

Morphological biodiversity and local use of the Himalayan pear (<Emphasis Type="Italic">Pyrus pashia</Emphasis>) in Central Bhutan

A survey was undertaken in two valleys of the Bumthang area in Central Bhutan to study the morphological diversity, farmers’ knowledge, management practices, yield and income generation potential of the neglected Himalayan Pear (Pyrus pashia Hamilton ex D. Don). For this study a total of 148 Pyrus pashia accessions were collected and 103 households interviewed. Three quantitative and 14 qualitative traits such as colour, size, shape and texture of fruits and tree habit were used for morphological characterization of the accessions. The results demonstrated a high morphological diversity within the P. pashia trees. Fruit shape varied widely from globose to pyriform, fruit skin colour from light yellow and glossy to brown and dull. The observed diversity is likely due to the fact that under farmers’ conditions trees are propagated through seedlings rather than by grafting. None of the characters were specific and correlated with region or altitude. Distinct local cultivars with specific characters were absent making it impossible to group the pears morphologically. Interviews revealed low numbers of trees per farmers, lacking marketability of the fruits and farmers’ subsequent preference for improved varieties as major obstacles for the in situ preservation of biodiversity in P. pashia in this area.     

Physico-chemical properties of tamarind (Tamarindus indica L.) fruits from Mali: selection of elite trees for domestication

Tamarind (Tamarindus indica L.) is a tropical fruit tree highly valued for its fruit pulp. It has been identified as one of the priority species with great potential for domestication in the Sahelian countries of Sub-Saharan Africa. An important step in the domestication process is the characterization of the local natural variation of the species in order to select the most interesting phenotypes/genotypes which possess several desired traits for breeding purposes. Four provenances covering contrasting agro-ecological zones in Mali were selected for fruit morphological and nutritional traits (tartaric acid and sugars). Tamarind trees from the driest provenance contained smaller fruits with a smaller amount of pulp compared to provenances from wetter zones. Tamarind trees in Mali have a low real pulp value (maximum 9.5) and bear sour fruits (high tartaric acid content of 9–12 %). Some sweet-fruited trees could be identified, but the sweetness was low (maximum 8). Fruit traits seem to be influenced by climate and soil characteristics, which should be taken into account in the domestication process, when planting trees in a different region of origin. We selected a few elite trees within each provenance, containing the best combination for the most desirable fruit traits, using web diagrams. Frequency distributions of the different fruit traits showed some traits are probably the target of selection by farmers. All provenances, except the driest one, indicated a possible very first stage of domestication.     

Reproductive biology and characterization of <Emphasis Type="Italic">Allanblackia parviflora</Emphasis> A. Chev. in Ghana

Allanblackia parviflora A. Chev. (Clusiaceae Lindley) is an indigenous tree species which is found in the rain forest regions of Ghana. It is a potential candidate fruit tree species being introduced in agroforestry systems. Information on genetic diversity, reproductive biology and fruit yield are not known. Field expeditions to seven populations of Allanblackia parviflora in Ghana were undertaken in 2003–2006 during which fruits were collected from 109 trees for characterization. The species was found to be dioecious. The colour of flowers varied from whitish to reddish. No ecological differences in number of fruits per tree, fruit shape and seed health were observed. However, large variations in fruit size and shape were observed among individual trees sampled. A high heritability (h ² = 0.822) in fruit size and genetic gain (G = 20.1%) in fruit size for selection of trees with above average fruit size were observed. A positive significant correlation was observed between fruit size and seed weight (R = 0.54, P < 0.05; Fig. 6). The results suggest that selection and cloning of trees with large fruits could lead to higher yield of seeds for oil production.     

Comparative study on baobab fruit morphological variation between western and south-eastern Africa: opportunities for domestication

The baobab tree (Adansonia digitata L.) is one of the key species for domestication in the semi-arid regions of Africa. In order to help select superior materials for cultivation, fruit morphological variation focussing on pulp content was studied in two physically isolated genetically different baobab populations: Mali and Malawi (West and south-eastern Africa, respectively). In each country eight study sites were selected following a climatic gradient, and their fruit characteristics were measured. Fruit morphology was correlated with climatic and soil data. Significant differences in fruit characteristics between countries and study sites within one country were observed. In general, fruits from Mali tended to be more elongated and their seeds were lighter than those from Malawi. Some sites had significantly high fruit weight and pulp percentage. The general trend (in both countries) was the hotter the environment the lower the pulp percentage, the more spherical the fruits and the smaller the seeds. Moreover, the wetter the environment, the higher the pulp percentage. Results from this study suggest that both genetics and the environment play roles in baobab fruit morphology. Although further research is needed to confirm whether baobabs producing desirable fruits keep producing the same fruits when grown in another environment, it seems that there is room for selecting high quality planting materials.     

Phenotypic Variation of Agromorphological Traits of the Shea Tree, Vitellaria paradoxa C.F. Gaertn., in Mali

Forty-one shea tree populations were sampled, spanning the main climatic zones of Vitellaria paradoxa Gaertn. in Mali and 10–35 adult trees were chosen randomly in the agroforestry parklands of each area. A total of 12 morphological traits, related to tree morphology, fruit size and leaf form were measured. The variance components showed that variation among populations represented the smaller percentage of the total variation with most of the values varying between 15 and 30%. The repeatability coefficient was generally high for tree within populations with values ranging between 0.23 and 0.78. Although genetic correlations cannot be accurately estimated, due to difficulties in separation from environmental effects, the results indicate that there is a very low genetic relation between the three kinds of traits, i.e., between those related to tree, those related to leaf and those related to fruit. Leaf and fruit size traits were positively and significantly correlated with rainfall, although tree circumference was negatively correlated with rainfall and the significantly larger shea trees were noted in the drier areas – an observation thought linked to human management of the parklands. Soil drainage and parkland density, however, did not explain differences between populations for fruit traits. This study offers preliminary information for the development of a breeding population for a shea tree improvement programme. The value of repeatability, the low correlation between sets of traits and the distribution of variation, suggest that selection of many individual trees within a few populations, would allow capture of large genetic gain especially for fruit traits.     

Morphological and molecular diversity of an underutilized fruit crop - <Emphasis Type="Italic">Cordia myxa</Emphasis> L. germplasm from the arid region of Rajasthan,India

Twenty two germplasm accessions of Cordia myxa were collected from Rajasthan and established at the field gene bank for conservation and evaluation. Morphological characterization of 10 year-old trees for 17 traits indicated wide variations among the accessions tested. Higher number of flowers per cyme was found in accession ACHM11 and higher pulp:stone ratio in AHCM25. Overall, AHCM22 was found to be a superior germplasm line for most of the horticulturally useful traits among the accessions tested as it had higher percent of fruit set, pulp:stone ratio and fruit weight. High significant positive correlation was obtained between leaf, fruit characters and pulp:stone ratio. However, these characters were found to be negatively correlated with number of flowers per cyme. Out of 50 random decamer primers used for random amplification (RAPD), 25 were polymorphic. Average polymorphism resolved by these markers among these accessions was 69.8% with an average polymorphic information content of 0.43. Genetic diversity revealed by Jaccard’s co-efficient was between 0.44 and 0.94, and three major clusters were identified among these accessions by phylogenetic analysis using NTSYSpc-2.02e software. RAPD markers associated with leaf size and pulp:stone ratio were also identified. This study shows the existence of high genetic diversity among these accessions.     

Morphological variation among shea tree (Vitellaria paradoxa subsp. nilotica) ‘ethnovarieties’ in Uganda

Vitellaria paradoxa C. Gaertn. (shea butter tree) is an indigenous African tree species that is widely distributed in the dry areas of northern and eastern Uganda. The species is widely known for its oil which is used in cooking, cosmetics and traditional medicine. Local folk classification recognises the presence of different ethno-varieties on the basis of fruit and nut characters. In the present study, 176 trees representing 44 ethno-varieties from three farming systems of Uganda were assessed to determine the patterns of morphological variation and establish the congruence between morphological variation and folk classification. The results show high variation in pulp weight (CV = 35.9 %), stem diameter (CV = 28.48 %), fruit weight (CV = 27.81 %) and canopy diameter (CV = 26.69 %). There was a strong positive correlation between pulp and fruit weight (r = 0.963, p < 0.001), leaf length and leaf width (r = 0.652, p < 0.001) and between petiole length and leaf length (r = 0.788, p < 0.001). There was no underlying quantitative morphological structuring among the 44 ethno-varieties. Hierarchical cluster analysis using quantitative morphometric data produced three groups without clear aggregation based on ethnographic or geographic separation. However, a combination with qualitative traits as perceived by farmers provided good congruence with folk classification. Quantitative morphological data alone does not resolve any discrete forms of V. paradoxa that are related to folk classification. There is need to utilise biochemical and molecular markers to unravel the underlying variation for use in selection and improvement of shea butter tree ethno-varieties.     

Morphological characterization of African bush mango trees (Irvingia species) in West Africa

The variation of the morphological characters of bitter and sweet African bush mango trees (Irvingia species) was investigated in the Dahomey Gap which is the West African savannah woodland area separating the Upper and the Lower Guinean rain forest blocks. African bush mangoes have been rated as the highest priority multi-purpose food trees species that need improvement research in West and Central Africa. A total of 128 trees from seven populations were characterized for their bark, fruits, mesocarp and seeds to assess the morphological differences between bitter and sweet trees and among populations. Multivariate analysis revealed that none of the variables: type of bark, mature fruit exocarp colour, fruit roughness and fresh mesocarp colour, could consistently distinguish bitter from sweet trees in the field. The analysis of the measurements of fruits, mesocarps and seeds demonstrated that bitter fruits have the heaviest seeds and this consistently distinguishes them from sweet fruits. However, the measurements of the fruit, mesocarp and seed did not have a joint effect in grouping types and populations of ABMTs. This indicates high diversity with a potential for selection existing across all phytogeographical regions investigated. The sweet trees of Couffo and those of Dassa in Benin are clearly different from all other populations. This can be attributed to traditional domestication (bringing into cultivation) and climate, respectively. The large fruits and the heavy seeds of the cultivated populations are evidence of successful on-going traditional selection of sweet trees in the Dahomey Gap.     

Phenotypic diversity and delimitation between wild and cultivated forms of the genus <Emphasis Type="Italic">Pyrus</Emphasis> in North-eastern Spain based on morphometric analyses

We investigated morphological evidence that might allow wild Pyrus spp. to be distinguished from cultivated material (Pyrus communis L.) in the North-eastern Iberian Peninsula. 134 pear trees were identified in the wild and characterized by 13 quantitative and 13 qualitative leaf–shoot and fruit traits. The trees were visually classified into two preliminary groups of wild and cultivated material and discriminant functions, based on a reference collection for allocating individuals to one of the groups, were constructed. Both classifications were compared with a near-optimal numerical classification (the two-stage Ward-MLM strategy) using two criteria. The visual assignment of trees allocated 60% of trees to the wild group and 40% to the cultivated group. The overall discrepancy rate between the field classification and the discriminant analysis was low (17.4%). In general, wild individuals had smaller leaves, shorter petioles and more rounded and smaller fruits than their cultivated counterparts. They also had small-to-intermediate petiole widths, thorns on their shoots and straight or convex fruit profiles. However, the Ward-MLM strategy always formed better groups, in terms of the two criteria used, in all the continuous and categorical variables, for both leaf–shoot and fruit traits. Likewise, the agreement between classifications (discriminant analysis and Ward-MLM strategy) was only partial, with some Ward-MLM groups composed of both wild and cultivated material in similar proportions. This result suggests a limited success in identifying genuine wild individuals based on morphometric data, which can be ascribed either to poor phenotypic diversity and lack of distinguishing traits among species or to widespread crossability and subsequent development of hybrid/introgressant populations between wild and cultivated specimens.     

Pear (Pyrus Species) Genetic Resources in Iwate, Japan

Iwateyamanashi (Pyrus ussuriensis Maxim. var. aromatica (Nakai et Kikuchi) Rehd.) is one of the Pyrus species grown wild in Japan. The origin of the Japanese pear (P. pyrifolia) is uncertain but it has been suggested that Iwateyamanashi is the possible progenitor of the modern Japanese cultivar. During the last few decades, the number of Iwateyamanashi trees has been decreasing and therefore, conservation is urgently needed. After 13 explorations in the northern Tohoku region of Japan, 615 pear trees and 30 local names were recognized mainly in Iwate Prefecture. The center of the distribution seemed to be somewhere around Mt. Hayachine to the northern area of Kitakami highlands (from lat. 39 °20′ to 40 °10′N, and from long. 141 °20′ to 141 °50′E). Four morphological characters concerning fruit shape, measured for 85 trees, showed a wide range of continuous variation. For the skin colour of fruit, 51% of trees bore russet type fruits, 22% smooth and 27% intermediate ones. Most of the fruits had five loculi but Sanenashi fruits (seedless pear), one of the old cultivars, had three, and fruits of another two trees had four. More than 80% of trees tended to produce fruits with a calyx but some trees bore fruits without a calyx. These observations indicate a wide range of genetic diversity in Pyrus species which is caused, not only by high heterogeneity in Iwateyamanashi itself, but also by the coexistence of Iwateyamanashi, P. pyrifolia (Burm.) Nakai and hybrid progeny in this area. Already 250 trees have been conserved as genetic resources by grafting at Kobe University.