Phenotypic variation in fruit and seed morphology of Adansonia digitata L. (baobab) in five selected wild populations in Malawi

Abstract

Adansonia digitata L (Baobab) is widely distributed throughout Sub-Saharan Africa stretching from Senegal to Sudan, and from Ethiopia to Natal. Information of phenotypic and genetic variation is a prerequisite for the domestication and improvement of baobab fruits from the wild. A study was done to determine within and between provenance variability in fruit and seed characteristics of five populations selected from four silvicultural zones and assess whether morphometric traits could delineate populations from different zones into land races. Fruits were characterized from 55 trees representing a wide geographical range. Six fruit traits and three individual seed traits were assessed. Results showed highly significant differences (P≤0.001) in fruit, pulp, and seed weight, fruit length and width, number of seed, individual seed weight, seed length and width within and between populations. Mean fruit weight ranged from 125.8 ± 3.25 g to 162.9 ± 3.25 g, seed weight ranged from 38.6 ± 2.5 g to 66 ± 2.01g and pulp weight ranged from 28.7 ± 1.33 g to 41.4 ± 1.33 g. Single seed weight showed pronounced evidence of divergence of populations into ecotypes. The rich diversity found between and within populations is important for domestication purposes and tree improvement through selection and breeding. All populations could be used for seed source but distribution should be consciously done recognizing existence of races.

The African baobab (Adansonia digitata, Malvaceae): Genetic resources in neglected populations of the Nuba Mountains, Sudan

“…The mean fruit lengths recorded in the current study (13.9–16.5 cm, Table 6) were in the range of those found by Sanchez et al (2011c) in Mali and Malawi (15.7–22.2 and 12.9–17.6 cm, respectively), as well as reported by Munthali et al (2012) from Malawi (11.9–16.5 cm). We used CV values to evaluate the impact of genetic or environmental factors on morphometric fruit traits.…”

Phenology of Sclerocarya birrea (A. Rich.) Hochst. Provenances

“…Despite that Chikwawa and Mangochi (Malawi) synchronized with Mudzi, Matebeleland North, Matebeleland South, Magamba, Ngundu (Zimbabwe), Siavonga (Zambia) and Kalimbeza (Namibia) genotypes but they are from different ecological zones in terms of latitude and altitude, this therefore may signify genetic influence [12,13]. This is in agreement with reports of Munthali et al, [17] where similarities in phenotypic and genetic attributes between geographically different populations of Adansonia digitata were attributed to genetic closeness. Consequently, the overlapping in flowering between populations, provide opportunities for hybridizing selections made in the populations without the need for storing pollen and conducting control pollinations which is expensive.…”

“…Tree to tree variations in fruit production are of paramount importance and commonly used by geneticists during selection for domestication and tree breeding. It offers a wider chance for a combined selection to be carried out both at provenance, family and individual tree level to attain high genetic gains [17,44]. Therefore, continued monitoring for fruit production and sex change among genotypes is required for several consecutive seasons before effecting selection of those trees that do not exhibit mast seeding.…”

Variation of seed sizes and its effect on germination and seedling growth of mahogany (Swietenia macrophylla)

“…As well as, research results on Dalbergia sissoo Roxb, (Singh et al 2011), Acacia tortilis (Abdelbasit et al 2014), Pinus ponderosa (Agera and Stettle 1983), Adansonia digitata (Munthali et al 2012) and Prunus nepaulensis (Shankar and Synrem, 2012) showed that the clonal effect was dominant on the size and weight of seeds. In fact, the seed size, related to genetics other than indicated by clones, is also shown by the relation of seed size and provenance, for instance on Jatropha curcas (Guan et al 2013), Adansonia digitata L. (Munthali et al 2012). Sclerocarya birrea (Mkwezalamba et al 2015) and Faidherbia albida.…”

“…Genetic factor is also indicated by some studies which were exploring the relationship of seed size and provenance (Ager and Stettle 1983;Singh et al 2011;Munthali et al 2012;Shankar and Synrem 2012;Munthali et al 2012;Guan et al 2013;Abdelbasit et al 2014;Fredrick et al 2015;Mkwezalamba et al 2015). Some characteristics of fruit and seed are influenced by environmental factors too, such as altitude, temperature and agronomic practices (Quarda et al 2008).…”