The study of floral biology in wild and cultivated species of cotton (Gossypium spp.)

A set of 14 different species and three interspecific hybrids of cotton were studied during 2019-2021 to evaluate floral morphology and reproductive biology. The mean performance of genotypes revealed variation for different characters among all the species studied. The highest number of anthers was found in ISH-P1 (interspecific hybrid plant) (174), followed by Gossypium raimondii (173). However, when tested for pollen viability, all three interspecific hybrids turned out to be sterile. Conversely, the wild species G. nelsonii showed the highest pollen viability (95.29%). The highest in-vitro pollen germination percentage was exhibited by G. herbaceum (89.4%), which also had the longest pollen germ tube length (924.03 µm). The length of the pedicle varied from 3.64 cm in G. barbadense to 0.34 cm in G. nelsonii. The tree species G. raimondii exhibited the longest style (43.96 mm), which was also a poor performer in terms of selfing (38.89%) and outcrossing potential (0%). Tetraploid G. barbadense had the largest pollen grains (121.12 µm), whereas the smallest were observed in G. trilobum (80.43 µm). The highest values of selfing (95.45%) and outcrossing potential (10%) were observed in desi cotton species G. arboreum and G. herbaceum, respectively.