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’ × Abelmoschus manihot. The interspecific F₁s 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 F₁s 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’ × 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.

Epigenetic changes such as DNA methylation and histone modifications, when meiotically inherited across generations, can act as a stable evolutionary force that is independent of any accompanying DNA mutations. Certain histone deacetylase (HDAC)-inhibiting chemicals such as Trichostatin A (TSA) and sodium butyrate are known to regulate the total acetylated histones in the genome, which is important for regulating the expression of various traits in all organisms. This study investigated all morphological variations in traits of Abelmoschus esculentus L. (okra) induced by different doses of Trichostatin A in a popular okra variety, Arka Abhay. Two sets of seeds were treated with two doses (0.4 µM and 1.2 µM) of TSA and were incubated in the chemical for three and five days, respectively, to record the effects of dose and incubation periods on various agronomic characters of okra. The treatment of TSA had a negative impact on the majority of the characters under evaluation. Total seedlings emerged, and mean shoot and root length were retarded following the TSA treatment. Extremely dwarfed plants with malformed leaves and flowers were a common observation. Pollen sterility combined with distortion of the reproductive whorls of the flowers were particularly pronounced at high doses with a prolonged incubation period. Treated plants had a significantly delayed first flowering and produced short fruits with altered morphology. Variations in seeds with respect to the number, colour and size were also recorded. Total reduction with respect to seedling parameters, total pollen production, the number of fertile pollens, plant height and other damaging effects on leaves, flowers, fruits and seeds increased as the dose and incubation period increased. Statistical analysis revealed the significant negative effect of TSA treatments on plant height, the number of ridges and locules per fruit, number of seeds per fruit and test weight. The treatment, 1.2 µM Trichostatin A incubated for three days, showed a remarkable difference as traits such as total field emergence, seedling parameters and days to first flowering plant height, number of seeds per fruit and test weight deviated from the expected trend of decreasing growth parameters as the dose and incubation period increased. The study further revealed that the treatment (1.2 µM TSA incubated for three days) can be suggested for use in okra to induce epigenetic variations without significantly compromising the growth and vigour parameters of okra.