Stochastic characteristics of the Benue River streamflow process are examined under conditions of data austerity. The streamflow process is investigated for trend, non-stationarity and seasonality for a time period of...Stochastic characteristics of the Benue River streamflow process are examined under conditions of data austerity. The streamflow process is investigated for trend, non-stationarity and seasonality for a time period of 26 years. Results of trend analyses with Mann-Kendall test show that there is no trend in the annual mean discharges. Monthly flow series examined with seasonal Kendall test indicate the presence of positive change in the trend for some months, especially the months of August, January, and February. For the stationarity test, daily and monthly flow series appear to be stationary whereas at 1%, 5%, and 10% significant levels, the stationarity alternative hypothesis is rejected for the annual flow series. Though monthly flow appears to be stationary going by this test, because of high seasonality, it could be said to exhibit periodic stationarity based on the seasonality analysis. The following conclusions are drawn： （1） There is seasonality in both the mean and variance with unimodal distribution. （2） Days with high mean also have high variance. （3） Skewness coefficients for the months within the dry season period are greater than those of the wet season period, and seasonal autocorrelations for streamflow during dry season are generally larger than those of the wet season. Precisely, they are significantly different for most of the months. （4） The autocorrelation functions estimated ＂over time＂ are greater in the absolute value for data that have not been deseasonalised but were initially normalised by logarithmic transformation only, while autocorrelation functions for i = 1, 2 365 estimated ＂over realisations＂ have their coefficients significantly different from other coefficients.展开更多
Initial sugarcane production in South Africa relied on imported varieties. When imported varieties succumbed to diseases, the industry established the South African Research Institute (SASRI) with the mandate to devel...Initial sugarcane production in South Africa relied on imported varieties. When imported varieties succumbed to diseases, the industry established the South African Research Institute (SASRI) with the mandate to develop sugarcane varieties. The popular and highly successful varieties, NCo310 and NCo376 were selected from crosses imported from India. NCo310 and NCo376 were grown successfully in several countries across the world where they produced high yield and ratooning ability. Later, crossing was established at SASRI based on flowers initiated in the glasshouse and photoperiod house under controlled temperature and photoperiod conditions. A five stage program is currently being implemented in the variety development process. More than 60 varieties have been released from the breeding programs. Other achievements include development of germplasm that is currently being used to enhance sugar cane variety development in South Africa. Currently, high realised selection gains are evident in most of the advanced selection populations. The released varieties show genetic gains over time. Efforts to enhance the breeding program include introgression, family evaluation, selection models and use of molecular markers.展开更多
基金Supported by the Post Graduate Research Fund from Federal Government of Nigeria under the BEA Scholarship Program （No.CSC2005566002）
文摘Stochastic characteristics of the Benue River streamflow process are examined under conditions of data austerity. The streamflow process is investigated for trend, non-stationarity and seasonality for a time period of 26 years. Results of trend analyses with Mann-Kendall test show that there is no trend in the annual mean discharges. Monthly flow series examined with seasonal Kendall test indicate the presence of positive change in the trend for some months, especially the months of August, January, and February. For the stationarity test, daily and monthly flow series appear to be stationary whereas at 1%, 5%, and 10% significant levels, the stationarity alternative hypothesis is rejected for the annual flow series. Though monthly flow appears to be stationary going by this test, because of high seasonality, it could be said to exhibit periodic stationarity based on the seasonality analysis. The following conclusions are drawn： （1） There is seasonality in both the mean and variance with unimodal distribution. （2） Days with high mean also have high variance. （3） Skewness coefficients for the months within the dry season period are greater than those of the wet season period, and seasonal autocorrelations for streamflow during dry season are generally larger than those of the wet season. Precisely, they are significantly different for most of the months. （4） The autocorrelation functions estimated ＂over time＂ are greater in the absolute value for data that have not been deseasonalised but were initially normalised by logarithmic transformation only, while autocorrelation functions for i = 1, 2 365 estimated ＂over realisations＂ have their coefficients significantly different from other coefficients.
文摘Initial sugarcane production in South Africa relied on imported varieties. When imported varieties succumbed to diseases, the industry established the South African Research Institute (SASRI) with the mandate to develop sugarcane varieties. The popular and highly successful varieties, NCo310 and NCo376 were selected from crosses imported from India. NCo310 and NCo376 were grown successfully in several countries across the world where they produced high yield and ratooning ability. Later, crossing was established at SASRI based on flowers initiated in the glasshouse and photoperiod house under controlled temperature and photoperiod conditions. A five stage program is currently being implemented in the variety development process. More than 60 varieties have been released from the breeding programs. Other achievements include development of germplasm that is currently being used to enhance sugar cane variety development in South Africa. Currently, high realised selection gains are evident in most of the advanced selection populations. The released varieties show genetic gains over time. Efforts to enhance the breeding program include introgression, family evaluation, selection models and use of molecular markers.
