Characterization of Okra Species, Their Hybrids and Crossability Relationships among Abelmoschus Species of the Western Ghats Region

Wild relatives of okra represent a good source of variation for breeding programs, particularly for traits related to biotic and abiotic stresses and fruit quality. However, wild species remain largely unexploited for okra breeding. The cultivated okra accession Abelmoschus esculentus cv. 'Arka Anamika' was crossed with three wild accessions: Abelmoschus manihot, Abelmoschus ficulens and Abelmoschus moschatus. The crossability was estimated based on fruit set, seed set and germination rate. The results of cross compatibility studies revealed that the crosses are compatible only when cultivated A. esculentus is used as a female, and reciprocal crosses were not successful in any of the three wild species. Higher fruit set (87.2%) and seed germination (92%) were obtained from the crosses 'Arka Anamika' x Abelmoschus manihot. The interspecific F(1)s exhibited normal growth, flowering and fruit formation, but the hybrids were completely sterile on selfing due to abnormal meiosis. Characterization of the parents and interspecific hybrids revealed that the interspecific hybrids were generally more vigorous than the parents and displayed greater alliance towards their wild parent. The sterile F(1)s were further treated with 0.1% colchicine to restore fertility. The three interspecific crosses showed considerable differences in mean performance and heterosis over mid parent and better parent. The cross 'A. Anamika' x A. manihot displayed positive heterosis over mid parent and better parent for the yield traits, viz., fruit yield per plant, number of fruits per plant, number of primary branches per plant and plant height. The information obtained in the study on crossability relationship, phenotypic characterization and heterosis in interspecific hybrids will assist breeders in the development of prebreeding material.

Automated summary

Wild relatives of okra are a good source of variation for breeding programs, especially for traits related to stresses and fruit quality. However, they have been largely unexploited so far. In this study, cultivated okra was crossed with three wild species, and the crossability was evaluated based on fruit set, seed set, and germination rate. Results showed that the crosses were only successful when the cultivated okra was used as the female parent, and reciprocal crosses were not successful. The interspecific hybrids exhibited normal growth but were sterile due to abnormal meiosis. Further treatments were conducted to restore fertility, and the hybrids showed differences in performance and heterosis. The information obtained in this study will help breeders develop better prebreeding material.