Correlation between Successive Yield Tests for Agronomic Characters in Sweet Potato

Abstract

Correlation coefficients over cultivars between successive yield tests in sweet potato (Ipomoea batatas [L.] LAM.) for yield and other agronomic characters were computed from breeding records for about 20 years to evaluate the accuracy of the yield tests. The means of the correlation coefficients between years were from 0.29 to 0.79 for root yield, from 0.58 to 0.88 for dry matter%, from 0.48 to 0.65 for root size, from 0.48 to 0.69 for roots/plant, and from 0.15 to 0.58 for general appearance, etc, . The correlation coefficients were generally higher in tests at advanced stages than at early stages. It was suggested that selection at early stages should emphasize dry matter% or nematode resistance, instead of root yield.