Genetic and morphological diversity in populations of Annona senegalensis Pers. occurring in Western (Benin) and Southern (Mozambique) Africa

Abstract

Background Understanding morpho-genetic diversity and differentiation of species with relatively large distributions is crucial for the conservation and sustainable management of their genetic resources. The present study focused on Annona senegalensis Pers., an important multipurpose wild plant, distributed exclusively in natural ecosystems but facing several threats. The study assessed the genetic and morphological diversity, structure, and differentiation of the species in populations from Western (Benin) and Southern (Mozambique) Africa. The material was evaluated to ascertain the environmental (climatic) determinants of the variation within this species. Methods Four sub-populations comprised of 154 individuals were phenotyped based on nineteen plant, fruit, and leaf morphological traits and further genotyped using ten polymorphic nuclear microsatellite (nSSR) markers. Results The results indicated strong differences in plant, fruit, and leaf morphological traits between Western and Southern populations. Furthermore, the studied populations were characterized by high genetic diversity, with an average genetic diversity index of 1.02. Western populations showed higher heterozygosity values (0.61–0.71) than Southern populations (0.41–0.49). Western and Southern populations were clearly differentiated into two different genetic groups, with further genetic subdivisions reflecting four sub-populations. Genetic variation between regions (populations) was higher (69.1%) than among (21.3%) and within (9.6%) sub-populations. Four distinct morphological clusters were obtained, which were strongly associated with the four genetic groups representing each sub-population. Climate, mainly precipitation and temperature indexes, explained the relatively higher variation found in morphological traits from Western (40.47%) in relation to Southern (27.98%) populations. Our study suggests that both environmental and genetic dynamics play an important role in the development of morphological variation in A. senegalensis.

The relative role of soil, climate, and genotype in the variation of nutritional value of Annona senegalensis fruits and leaves

“…Therefore, someone selecting those populations for their high content in some parameters should be aware that they are also selecting materials with lower contents in other proximate composition parameters. Our findings in previous studies showed genetic differences within and among populations from Benin and Mozambique [ 25 ]. These populations are also subject to different climatic conditions and grow on different soils [ 25 ].…”

“…Our findings in previous studies showed genetic differences within and among populations from Benin and Mozambique [ 25 ]. These populations are also subject to different climatic conditions and grow on different soils [ 25 ]. This offers an interesting opportunity to test how factors such as genetic variation, climate, and soil properties can solely and interactively affect the nutritional composition of the edible parts.…”

“…Moreover, some values obtained for ashes in populations from Benin were similar to those found in Mozambique, particularly in Mavago, and some values found for lipids in populations from Mozambique were similar to those found in Benin, particularly in North Borgou. Since the studied populations are genetically different [ 25 ], it appears that the observed variation in the proximate composition of A. senegalensis fruits and leaves is not only due to genetic differences among populations, but that other factors are also driving these variations. For instance, the redundancy analysis showed some influence of soil parameters.…”