Characterization and Cross-Compatibility in Interspecific Hybridization of Jute (Corchorus spp.)

Abstract

Jute (Corchorus) species are widely distributed and cultivated for fibers, vegetables and traditional medicine throughout the tropics, subtropics and temperate regions. The objectives of this study were to (i) characterize the three Corchorus species (Corchorus olitorius, Corchorus incisifolius, and Corchorus tridens); and (ii) investigate the cross-compatibility of interspecific hybridizations within the genus Corchorus. The three Corchorus species were evaluated at botanical garden of University of Ilorin in 2016 and were crossed in all possible combinations using hand emasculation procedures to generate F1 hybrids. Analysis of variance (ANOVA) was performed on the agronomic data collected on them. The difference between means was separated by the least significant difference (LSD). The percentage of successful and aborted crosses was calculated. The results obtained from the analysis revealed that Corchorus incisifolious shared common characteristics (monomorphic) with Corchorus olitorius such as yellowish leaf-lamina, glabrous hairiness, and medium seed-size, whereas Corchorus tridens had wine coloration in its leaf-lamina, pubescent hairiness of leaf, and small seed-size. Thus, the three species differed in some qualitative characters (dimorphic or polymorphic), such as leaf shape, seed coat color, and leaf apex, which were proposed diagnostic features. Corchorus incisifolious had the most leaves, longest pod, and widest pod based on quantitative characters. About 121 crosses were attempted between the three species of Corchorus using hand emasculation method, but only one cross combination was successful between Corchorus olitorius and Corchorus incisifolious (4.76%) out of 21 attempts, while other cross combinations failed. Therefore, qualitative characters are good genetic markers to distinguish cultivated Corchorus species, while sexual barrier and other factors were suggested to be responsible for the low success rate recorded in this study. Hence, biotechnology techniques (in vitro pollination or embryo rescue) can be used to overcome these barriers.