Natural crossing in cotton

Inflorescence Architecture: How Flower Number, Arrangement, and Phenology Affect Pollination and Fruit-Set

“…These same principles should apply to a population of flowers within an inflorescence or to a population of inflorescences on an individual plant. The same techniques used for tracing pollen flow between plants such as the use of dyes (Thies, 1953;Stephens and Finkner, 1953;Simpson and Duncan, 1956;Sindu and Singh, 1961), of radioactive isotopes (Schlising and Turpin, 1971), or of neutron activation analysis (Gaudreau and Hardin, 1974;Handel, 1976) could be applied profitably to inflorescences. In milkweeds (Asclepias) self-pollination effected by crosses between flowers within the same inflorescence or between inflorescences on the same plant has been suggested as an important factor in restricting fruit-set to levels of 1% (Wyatt, 1976(Wyatt, , 1978 and in setting an upper limit on inflorescence size (Wyatt, 1980).…”

Senecio L. (Asteraceae) in Australia: Reproductive biology of a genus found primarily in unstable environments

“…Studies have shown that most dispersal units, whether they be seeds or pollen grains, travel comparatively short distances from the parent plant (Colwell 1951;Stephens and Finkner 1953;Salisbury 1961;Sheldon and Burrows 1973;Stergios 1974) and that dispersal over more than a few metres is a rare event. Seeds of all species examined in this study possess a pappus and are dispersed by wind but differences in both pappus morphology and the ratio between pappus and seed size appeared to affect dispersal distance.…”

Evolutionary Biology

“…In cotton, Thies (1953) treated 21 flowers in the edge row of a ten-row block and found that after 2 hr every flower had been dusted. In other studies on cotton (Stephens and Finkner, 1953;Simpson, 1954), dye was found on nearly all flowers in the vicinity of the donors and up to 27 m away. In one -experiment with methylene blue, Sindu and Singh (1961) determined that the percentage of recipient flowers decreased from 48% at 6 m to 18% at 12.2 m, 6% at 15.2 m, and 2% at 16.7 m. Although the technique is simple and has appeal, a compelling relationship between dye dispersal and pollen dispersal has not been established.…”