Response of flower and boll development to climatic factors before and after anthesis in Egyptian cotton

Abstract

Understanding the impact that climatic factors have on cotton production may help physiologists to determine possible control mechanisms which influence the flowering of cotton plants. This study was conducted to investigate the nature of the effects of climatic factors prevailing prior and subsequent to either flowering or boll setting on flower and boll production and retention in Egyptian cotton Gossypium barbadense L. Two uniform field trials using the cotton cultivated variety Giza 75 were carried out at the Agricultural Research Center, Giza, Egypt. Randomly chosen plants were used to record daily numbers of flowers and bolls during the production stage (68 d in Season I and 62 d in Season II). The daily records of the climatic factors (air temperature, diurnal temperature range, evaporation, soil surface temperature, sunshine duration, and humidity) were recorded during the entire period of production and also for the 15 d periods before and after anthesis. The effects of climatic factors on flower and boll production were quantified in non-limiting management techniques. Relationships in the form of simple and multiple correlations were computed between climatic factors and flower and boll production and retention. The data indicated that evaporation, minimum humidity and sunshine duration were the most effective climatic factors during preceding and succeeding periods on boll production and retention. There was a negative correlation between flower and boll production and either evaporation or sunshine duration, while the same correlation with minimum humidity was positive. Thus, it appeared that low evaporation rate, reduced sunshine duration and high humidity would enhance flower and boll formation. Accordingly, the deleterious effects of climatic factors on cotton production could be minimized through applying appropriate production practices, which would control and adjust the impact of these factors and thus potentially lead to an important improvement in cotton yield in Egypt.KEY WORDS: Boll retention · Evaporation · Flower and boll production · Humidity · Sunshine duration · TemperatureResale or republication not permitted without written consent of the publisher

Applied methods for studying the relationship between climatic factors and cotton production

“…The climatic factors (independent variables) considered were daily data of: maximum air temperature (˚C, X 1 ); minimum air temperature (˚C, X 2 ); maximumminimum air temperature (diurnal temperature range) (˚C, X 3 ); evaporation (expressed as Piche evaporation) (mm·day −1 , X 4 ); surface soil temperature, grass temperature or green cover temperature at 600 h (˚C, X 5 ) and 1800 h (˚C, X 6 ); sunshine duration (h·day −1 , X 7 ); maximum relative humidity (max RH) (%, X 8 ), minimum relative humidity (min RH) (%, X 9 ) and wind speed (m·s [13].…”

“…In each season, the data of the dependent and independent variables (68 and 62 days) were regarded as the original file (a file which contains the daily recorded data for any variable during a specific period). Fifteen other files before and another 15 after the production stage were obtained by fixing the dependent variable data, while moving the independent variable data at steps each of 1 day (either before or after production stage) in a matter similar to a sliding role [13] Thus, the climate data were organized into records according to the complete production stage (68 days the first year and 62 days the second year) and 15 days, 14 days, 13 days… and 1 day periods both before and after the production stage. This produced 31 climate periods per year that were analyzed for their relationships with cotton flowering and boll production [13].…”

“…However, by determining the relationship of climatic factors with flower and boll production and retention, the overall level of production can be possibly predicted. Thus, an understanding of these relationships may help physiologists to determine control mechanisms of production in cotton plants [13]. Daily records of the climatic factors (independent variables) were taken for each day during production stage in any season including two additional periods of 15 days before and after the production stage ( Table 4).…”

“…This could pave the way for formulating advanced predictions as for the effect of certain climatic conditions on production of Egyptian cotton. It would be useful to minimize the deleterious effects of the factors through utilizing proper cultural practices which would limit and control their negative effects, and this will lead to an improvement in cotton yield [13]. 3) Further, provide information on the effect of various climatic factors and soil moisture status during the development stage on flower and boll production in Egyptian cotton.…”

Safety Assessment of Transgenic Organisms, Volume 4

“…Carefully timing the application of water optimises the plant's vegetative growth, flowering and boll production (McWilliams, 2003). Flower and boll formation in G. barbadense are enhanced by a short duration of sunshine, high minimum humidity and low evaporation rate (Sawan et al, 2004(Sawan et al, , 2005. …”