Combining ability analysis of yield and late blight (Phytophthora infestans (Mont.) de Bary) resistance of potato germplasm in Rwanda

Designed crosses among complementary parents and combining ability analysis are essential to recombine traits of economic importance and to select novel genotypes. The objective of this study was to estimate combining ability effects for yield and yield related traits and late blight resistance in potato. Crosses were performed using a 10 × 10 half diallel mating design to generate 45 F1s. Only 28 families with sufficient individuals and eight parents were field evaluated in experiments laid out in a 6 × 6 lattice design with two replications across two sites (Kinigi and Nyamagabe) in Rwanda. Late blight resistance was estimated using the relative area under the disease progress curve (rAUDPC: 100 % max). Furthermore, data on total tuber yield, total tuber number, and average tuber weight were collected and subjected to combining ability analyses. Results showed that additive gene action and nonadditive gene action were present affecting yield and late blight resistance in potato. Additive gene action was predominant over nonadditive gene action for both traits. All the families selected for further evaluation showed improved levels of late blight resistance and high yields. The study identified ten top families with high tuber yield and resistance to late blight for further evaluation and release.