Relationship between tuber number and tuber size in reciprocal grafts of some sweet potato (ipomoea batatas (L.) Lam.) clones – O.A.T.Namo
Six sweet potato clones, Ex-Igbariam, TIS.87/0087, TIS.2532.OP.1.13, CIP 4400168, TIS.86/0356 and TIS.2544 Rusanya 1.5, were used in a reciprocal grafting study during the wet season of 2003. The study was aimed at relating the tuber number to tuber size and the total tuber yield. Thirty-six (36) treatments were distributed to the plots using the randomized compete bock design with four replications. Results showed that tuber length and tuber girth were negatively, although non-significantly correlated with mean number of tubers/plant with coefficients of correlation of -0.234 and -0.004, respectively. Numbers of small and large tubers were positively and significantly correlated with mean number of tubers/plant with coefficients of correlation of 0.990** and 0.381*, respectively. Number of tubers/plant, tuber length, tuber girth, number of large tubers/plant and number of small tubers/plant were highly correlated with total tuber yield, with coefficients of correlation of 0.638**, 0.165, 0.545**, 0.815** and 0.449**, respectively. The study revealed that although tuber number is one of the major components of total yield in sweet potato, its relationship with tuber length and tuber girth appeared to be asymptotic. In selecting sweet potato clones for high yield, therefore, emphasis should be placed not necessarily on tuber number but on tuber size.