Two field experiments were carried out at lJ1allawi Agric. Res. Station, Minia
Governorate, in 2002 and 2003 seasons to study the response of Giza 83 cotton
cultivar to foliar application of the growth regulator Amcotone which contains 1-
naphthyl acetic acid (NAA) and 1-naphthyl acetamide (NAAM). Besides the control
treatments, Amcotone was used at the rates of 1.(1, 1.2 and 1.4 g/l. applied once at
the beginning of flowering stage (BF) or twice at SF and 15 days later. Results of this study reveal that some treatments of Amcotone exhibited
significant increases in leaves content of chlorophyll 3, total chlorophyll, poly phenols,
total phenols, number of open bolls/plant and seed cotton yield/fad. However, it
exerted a significant reduction in leaves content cf reducing sugars, total soluble
sugars, number of aborted fruiting sites/plant and bud and boll shedding%. The
application of Arncotone had no significant effect on plant growth characters. number
of sympodia/plant. total fruiting sites/plant, number c f unopen bolls/plant, boll weight,
earliness%, lint% or seed index in both seasons. The application of Amcotone at the rate of 1.2 gil. either one or two times of
application produced the highest seed cotton yielc and gave the best results in
general during the two studied seasons. It could be concluded that spraying cotton plants with the growth regulator
Amcotone exerted some biochemical and physiotoqical effects which reduced bud
and boll shedding and increased boll retention and yield production