Abstract:
In this study, cytological observation of cotton fiber initiation from 1 d before anthesis to 3 d post anthesis (dpa) was performed using a scanning electron microscope. Six cotton chromosome segment introgression lines and their recipient/donor parents were used as materials. Results showed that fiber cell protrusions were highly related to genotype and germplasm, but fiber cell elongations were closely related to lint percentage. Fiber cell protrusions and elongations
initially formed on the funicular crest, extended to the chalaza cap and the middle part of the ovule, and finally reached the micropyle. Fiber protrusion density at 1 dpa and elongation density at 2 dpa were observed in the following parts from highest to lowest: funicular crest > chalaza cap > middle part of the ovule > micropyle. The fiber protrusion density at 1 dpa and the fiber elongation density at 2 dpa were positively correlated with lint percentage and lint index but negatively correlated with seed index. The results of gray relational analysis were consistent with the correlation analysis results. Early fiber elongation contributed positively to protrusion density and elongation density, thereby resulting in a high lint percentage.
