Diversity of finger millet (Eleusine coracana (L.) Gaertn.) genotypes on drought tolerance and yield in Tanzania

A THESIS SUBMITTED IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY OF SOKOINE UNIVERSITY OF AGRICULTURE. MOROGORO, TANZANIA.

Studies were conducted to assess the morphological, physiological and genetic diversity of finger millet genotypes with respect to yield and drought tolerance in Tanzania. Alpha lattice field experimental design was used in morphological characterization of 169 Tanzania finger millet genotypes and complete randomized design for drought and yield evaluation experiments. Morphological descriptors used were plant height, number of productive tillers per plant, number of fingers per panicle, number of leaves per plant, time to plant maturity, yield per plant and thousand grain weights. Data were analyzed using descriptive statistics and correlation matrix, dendrogram and cluster analysis techniques. Plant yield was found to be significant (P ≤ 0.05) and positively correlated with number of productive tillers, plant maturity, and number of fingers per panicle, finger length and thousand grain weights. Analysis for principal component was done to determine contributing factors to finger millet diversity. The number of tillers, thousand grain weight, plant maturity and number of fingers per panicle were identified as important traits contributing to diversity and yield variability among finger millet genotypes in Tanzania. Thirteen SSR markers recovered polymorphic information content ranging from 0.31 to 0.79, indicating very high genetic diversity of the finger millet genotypes. The Markers detected 114 private alleles, which can help in advancing molecular breeding using techniques such as next generation sequencing to identify the genotypes possessing those identified private alleles. Principal coordinate analysis showed 42% genotypes’ variations within and 55% genotypes variations across locations and 3% genotypes’ variations between locations. Cluster analysis discriminated 169 finger millet genotypes into a phylogeny tree of 13 distinct clusters. Drought phenotyping using yield stability, drought resistance and stress tolerance indices identified genotypes TFA 77, TFA 169 and TFA 11 to be superior drought tolerant and high yielding genotypes under terminal drought stresses. Determination of adaptation and stability of finger millet genotypes across finger millet production agro-ecologies targeting release of improved varieties for immediate farmers’ use in Tanzania is recommended. Integrated physiological, molecular and morphological characterization is recommended for large number of genotypes screening for drought tolerance using morphological and physiological traits associated with grain yield for finger millet variety development in Tanzania.