Improving breeding efficiency for quality and yield of sweet potato

Sweet potato is one of the most economically important crops in the world. This study obtains information on maternal effect on yield and quality traits of sweet potato under the following designed reciprocal crosses: 'Nancy Hall' (NH) x 'Tainung 27' (TN27), and 'Chingshey purple' (CP) x 'Tainung 57' (TN57). The reciprocal crosses were conducted at the same location in different years. Four populations of 119, 112, 200 and 200 plants form NH x TN27, TN27 x NH, CP x TN57, and TN57 x CP crosses, respectively, were used to investigate the inheritance of commercial traits. The correlations between traits were also analyzed. The results indicate that substantial differences of mean and coefficient of variation in the measured traits existed in the F₁ populations. Maternal effects on top weight and root weight between progeny groups have been observed using NH and TN57 as the seed parents. Top weight, storage root weight, and crude protein content of the hybrids were heterotic. The distributions of top weight, weight and number of storage roots were skewed toward low yield characteristics. Significant positive correlations were detected among top weight, weight, and storage root number, between storage root shape and top weight and storage root weight, between skin color and flesh color of storage root, and between starch content and amylose content. Selecting lower starch or amylose content may be useful to improving sugar or crude protein content in view of the significant negative correlation between these traits. Choosing a maternal parent of the breeding hybrid for the yield and quality should effectively improve the selection scheme.