No abstract

The objectives of the study were to assess the inter-relationship between growth, yield, nutritional and anti-nutritional responses of thirteen tannia (Xanthosoma sagittifolium L.) accessions to planting date (May, June and July) in the humid tropics. Tannia corms and leaves are veritable sources of dietary fibre and starch, also essential minerals and vitamins; hence its value for security and as a cash crop for people in the humid tropics. A two-year 13-genotype × 3 planting date factorial arranged rain-fed field experiment in randomized complete block design with three replications was carried out during the 2014 and 2015 cropping seasons at Michael Okpara University of Agriculture, Umudike, Nigeria. The results indicated that planting date and accession influenced growth and yield of tannia, an indication of differential responses of the thirteen accessions to the planting dates (May, June and July). The results suggest that May is the most appropriate planting date; accessions planted during this month had the highest yields. The interaction between planting date and tannia accession was significant for some traits (number of leaves per plant and cormel weight per plant) in both years and significant for plant height, pseudo-circumference and corm weight (2014); leaf area and tannia yield (2015). The correlation analysis showed good selection characters in plant height, pseudo-stem circumference, leaf area, number of leaves per plant, corm weight, corm circumference, cormel weight and cormel circumference for high yielding varieties, while nutritional analysis (crude protein, carbohydrate, phosphorus, potassium, calcium, tannin and oxalate) exhibited lower concentrations in processed corms relative to unprocessed. The corm yield of the tannia accessions ranged from 1.49 to 13.48 Mt.ha−1 in 2014 and 2.72 to 8.50 Mt.ha−1 in 2015 and best four accessions judged by interaction between tannia accession and date of planting was 13 (Ikaro) > 12 (Idoani) > 3 (Ehor) > 10 (Idasen) in May 2014 compared to accessions 6 (Ewu) >10 (Idasen) > 12 (Idoani) > 1 (Ikpoba) planted in June 2015. The differences in sequence suggest that both environment and genetic constitution contribute to Tannia yield.