Field trials were conducted during 2008, 2009 and 2010 seasons at the Institute for Agricultural Research (I.A.R) Farm Samaru to determine the relationship between growth and yield components related traits in physic nut that could be used as a basis for selection programme aimed at improving yield. The treatments consisted of two propagation methods (seeds and stem cuttings), four weed control treatments (Fusilade plus Diuron at 1.0 + 0.8kg a.i ha-1, applied at 4 and 12 weeks after transplanting (WAT), followed by supplementary hoe-weeding at 16 weeks; Atrazine plus Diuron at 1.0 + 0.8kg a.i ha– 1,, applied at 4 and 12 WAT, followed by supplementary hoe-weeding at 16 weeks; hoe weeded at 4,8,12 and 16 WAT and a weedy check) and three levels of nitrogen (0, 50 and 100kg ha-1). The treatments were laid out in a split-plot design and replicated three times. Nitrogen levels and weed control treatments were assigned to main plots, while the propagation methods were assigned to the sub plots. Data were taken on growth and yield components and simple correlation and path coefficient analysis were deployed to study the relationship among the growth and yield components to seed yield. Results indicated that the relationship between yield of physic nut was positively and highly significantly correlated to growth and yield components such as stem girth, plant height, canopy spread, number of leaves, leaf area index, crop vigour score, number of primary branches, weight capsule-1, capsule weight plant-1, 100 seed weight, number of capsule plant-1, shelling percentage, number of seeds capsule-1, seed weight capsule-1 and seed weight plant-1. However, weed cover score and weed dry weight were negatively and highly significantly correlated with yield of physic nut. The positive association of growth and yield components with these characters indicates that selection based on these characters could improve yield. From the study, it can be concluded that parameters like plant height, number of leaves, leaf area index, 100 seed weight and number of seeds per capsule are major contributors to Jatropha seed yield and therefore, can be suggested for breeding programme for seed yield improvement.
Key Words: Path analysis, Seed, Stem cuttings, Weed control, Nitrogen, Physic nut and Correlation