Estimates of Genetic Parameter Contributing to Early Bulkiness of Yellow Root Cassava (Manihot esculenta Crantz) Genotypes in Niger State, North Central Nigeria

Genetic variability among different genotypes for root yield component characteristics was studied in Guinea Savannah Agroecological zones of Niger state to determine its effect on early root bulkiness. Sixteen parameters were evaluated in 420m2 at spacing of 1mx1m in a randomized complete block design in three replicates. Cassava genotypes were evaluated at 3 and 6 MAP (Month After Planting) to evaluate root bulkiness. REML/BLUP showed significant difference among genotypes for different harvesting periods for Harvest Index and fresh storage root yield (FSRY). Estimates of genetic variance for phenotypic (PCV) and genotypic coefficient of variation (GCV) were very close. PCV estimates were higher than GCV and varied from 39% to 13% for root weight and root size respectively. Broad sense heritability estimates were high for FSRY and ranged from 81% to 8% among root yield components. GCV estimates was higher for harvest index (34%) and least for number harvested (6.15%). Heritability was highest for fresh storage root yield (81%) and least for shoot weight (0%), Environmental coefficient of variation was least for harvest index (HI) with 0.36 and shoot weight had the highest coefficient of variation and the least being for harvest index. Genotype IKN120036 performed best among the genotypes with 3.61tha-1 and had the highest genetic gains in terms of selection criterion FSRY. FSRY and HI had higher heritability and were strongly correlated (R= 0.61). Root number was not significant(P>0.05; R=-0.24) and negatively correlated with FSRY.