Effect of Shading at Different Stages of Growth of the Cotton Plant on Flowering and Fruiting, Boil Shedding, Yield of Seed Cotton and Earliness

الملخص

This investigation was conducted to study the effect of shading at different stages of growth on flowering and fruiting, boll shedding, yield of seed cotton and earliness.
The effect of shading on flowering activity was more pronounced during the time of the start of flowering. Shading cotton plants at the start of flowering caused a reduction in flowering and complete boll shedding comparable with that resulting from continuous shading. Shading during 3 weeks before the start of flowering increased the number of flowers, but boll shedding percentage was increased and the number of bolls and yield of seed cotton were decreased.
Shading cotton plants six weeks before the start of flowering caused a significant reduction in flowering and fruiting.
The effects of shading during the different periods following the start of flowering were almost similar, and no significant differences were obtained between them in boll shedding, yield and yield components.
Earliness decreased to a large extent when shading was started before the start of flowering and was not much affected when it was carried out late after the time of the start of flowering.