Full diallel crosses in superior parents of Jatropha curcas L

Abstract Contrary to most studies which reported on J. curcas improvement through half-diallel crosses of inbred lines, this study attempted to exploit the hybrid vigour of progenies through full diallel crosses of homozygous parental plants. In this study five superior plants of Jatropha curcas L., chosen after two years of evaluation, were crossed in full diallel fashion from August to December 2015 to determine the heterotic response in offspring from a 5 × 5 full diallel cross and its reciprocals. The offspring of the crosses and one control (designated as P2 × P5, an advanced breeding line suggested by a previous study) were planted and evaluated at the Biodiesel Research Station of Universiti Kebangsaan Malaysia, Kuala Pilah, Malaysia. Evaluation of seed weight (SWt) and seed length (SLT) started two months after crossing and evaluation of plant height (PHT), branches per plant (BPP), and basal stem diameter (BSD) began 18 months after sowing. Four out of five traits (SWt, SLT, PHT, and BPP) were significantly different at P ≤ 0.01 among the progeny. Superiority in SWt over mid-parent, better parent, and control ranged from −26.81 % to 37.13 %, −35.37 % to 23.72 %, and −34.61 % to 6.05 %, respectively whereas for BPP it ranged from −50.45%–90.48%, −63.33% to 66.67%, and −34.69% to 71.43%, respectively. Principal Component Analysis revealed SWt was highly and positively correlated with SLT, whereas BPP was highly and positively correlated with PHT. Choosing hybrids superior for SWt and BPP should be considered for the development of high yielding varieties.