Enhancement of cotton boll retention by GA3 treatment

Cotton (Gossypium spp.) is number one cash crop in the Sudan and is widely grown in irrigated and rainfed areas. It occupied a total area of about one million acres producing about one million bales of lint (Mursal, 1988), and there is a great potentiality to rank on the top of exports. Cotton quantity and quality improvement could be achieved by hybridization. Intraspecific and interspecific crossing is one of the ways to transfer desirable gene(s) combinations for crop improvement. One of the limitations that face the cotton crossing process is the high flowers and bolls shedding after pollination particularly in interspecific hybridization. During the course of an ongoing program to transfer resistance to bacterial blight from diploids to tetraploids cotton, we experienced excessive boll shedding after pollination. Therefore, the present study was conducted to investigate the effect of GA3 on flower and boll retention after pollination. The study was conducted at the Gezira Research Station (GRS), Wad Medani, Sudan, during the seasons 2001/02 and 2003/04. Two cultivars, Barakat-90 (G. barbadense) and Barac (67)B (G.hirsutum) were sown on ridges 80 cm apart and 50 cm between holes and the usual cultural practices were followed. GA3 was used at a concentration of 100mg/L (Baisakh et al., 1998). Flowers were emasculated in the afternoon-to evening and covered with paper bags to be pollinated in the next day morning. The emasculated flowers were sprayed once by the hormone using a small sprayer and bagged again. Four treatments for the application GA3 were used: GA3 applied before pollination, AG3 applied with pollination, GA3 applied one day after pollination and the control. Each treatment was applied on 10-12 flowers for each cultivar. The four treatments and the two cultivars were tested in a randomized complete block design with two replications. Shedded flowers were counted after 10 days. Each season data was subjected to arcine transformation. Analysis of variance was performed for each season and combined data