Investigation on Cross-Compatibility Barriers in the Biofuel Crop Jatropha curcas L. with Wild Jatropha Species

摘要

Interspecific hybridization in Jatropha species plays a significant role in crop improvement by transferring useful traits such as yield, high oil content, maximum number of seeds, more femaleness, and hard stems for promoting Jatropha as a biofuel crop. The wide crosses among the species resulted in limited success due to pollen incompatability. Hence, the objective of the study was to assess pre- and postzygotic barriers through pollen–pistil interaction between cultivated Jatropha curcas and other three wild Jatropha species. In this study, the cross J. curcas x J. gossypifolia, even though the pollen tubes reached ovaries after pollination, failed to produce seeds, and the cross between J. curcas x J. podagrica indicated incompatibility signs of bulged pollen tubes coupled with reverse direction of pollen tube growth. The interspecific cross of J. curcas with J. villosa showed crossability barriers of crinkled and twisted growth pattern of pollen tubes and failed to reach ovary. In the case of selfing (J. curcas x J. curcas), pollen tubes reached ovary within an hour and produced normal seeds. Reciprocal crosses of these species exhibited successful fertilization of pollen tubes, but seed set was very low or no seed set was noticed.