Relationship between some growth parameters, dry matter content and yield of some sweet potato genotypes grown under rainfed weathered ultisols in the humid tropics

Abstract

A field study was initiated to generate information on dry matter yield and some biometric parameter effects on yield of seven sweet potato genotypes in weathered ultisols in the humid tropics. The experiment, which was laid out in a randomize complete block design with four replications was conducted at National Root Crops Research Institute, Umudike, Abia State, Nigeria (05°29'N, 07°32'E,122 m asl). Umuspo 1 (31.2 t ha -1), closely followed by TIS 87/0087 (27.45 t ha -1) significantly (p<0.01) gave the highest storage root yield compared to the other genotypes and also exhibited highest Bulking Rate (BR) (7.78 g day -1), Total Dry Matter yield (TDM) (71.99 g plant -1), Crop Growth Rate (CGR), Relative Growth Rate (RGR) and Absolute Growth Rate (AGR). High yield of Umuspo 1 was partly due to greater partitioning of assimilates to the storage roots relative to the other genotypes. The mean sequence of TDM content and BR at 56 Days after Planting (DAP) in the genotypes was in the order: Umuspo 1>Solomon 4 > Ex-Igbariam>TIS 87/0087>TIS 8164>Umuspo 3>Centinneland Umuspo 1 >TIS 87/0087>TIS 8164>Solomon 4>Ex-Igbariam>Umuspo 3>Centinnel, respectively. Storage root yield had significant (p≤0.01) and positive correlation with number of storage roots/plant with correlation coefficients (r) of 0.53, bulking rate (r = 0.99), crop growth rate (r = 0.59), absolute growth rate (r = 0.59) and total dry matter at 2, 4, 6 and 8 weeks after planting. Umuspo 1 may be adjudged to be better endowed genetically because of its high dry matter content, early bulking ability and high yield potential recorded in the study.