Genetic variation among and within provenances of Adansonia digitata L. (Baobab) in seed germination and seedling growth from selected natural populations in Malawi

Abstract

Baobab (Adansonia digitata L) trees have a wide variety of subsistence and economic values across sub-Saharan Africa. Knowledge of the genetic variation within and between the species is essential for management and designing domestication, improvement and conservation strategies. Fifty-nine half-sib families were evaluated in the nursery to determine the genetic variation and control within and between the populations from four silvicultural zones. Seed germination and seven seedling growth parameters were assessed. Total phenotypic variance, family variance, within family variance, individual narrow sense heritability, and additive genetic coefficient of variation (AGCV) were derived from observed and expected mean squares. There were highly significant differences in seed germination, plant height, root collar diameter, number of leaves, shoot height and diameter, tuber diameter and weight. Provenance variation in germination ranged from 46.7 ±3.3% to 68.7±3.3% while tree –to- tree variation ranged from 6.3±8.6% to 95.5±8.6%. Coefficient of variation in seedling growth variables ranged from 18.6% to 43.6%. Individual narrow sense heritabilities (h2) ranged from 0.07 to 0.71. AGCV ranged from 3.21% to 14.67%. Morphological traits showed that mainland populations were genetically distant from the island one. High and moderate additive genetic control of traits and AGCV show the potential that Baobab can also respond well to tree improvement. High phenotypic variation found in the study offers an opportunity to effect selection of superior attributes at both provenance and individual tree-to-tree level.