Banana Yield Estimation (Dryland Ratoon Crop)

Modern bananas originated in the southeast Asian and western Pacific regions, with earliest records of cultivation in India about 2 500 years ago (ARC, 2005). Bananas are stress sensitive plants which grow satisfactorily with a MAP of 1 200 mm, ideally well distributed throughout the year (Smith, 1998). Dry spells of more than 7 days are detrimental to yields. Preferring a relative humidity > 60 percent (especially during fruit setting), the mid-day RH should generally exceed 50 percent. The optimum mean monthly temperatures for bananas are 25 - 28 degree Celsius, with a range of 20 - 35 degree Celsius. Growth ceases below 12 degree Celsius and the July mean of daily minima should be at least 8 degree Celsius. Of the 1 200 ha under bananas, 64 percent are in Mpumalanga, 18 percent are in KwaZulu-Natal and a further 18 percent in Limpopo (Statistics SA, 2002). Highest average yields, around 26 t/ha/an, are attained in Mpumalanga, while those in KwaZulu-Natal and Limpopo are 20 t/ha/an, i.e. on the low side by international standards (Statistics SA, 2002). Determination of banana yield estimates, based on Smith`s climatic criteria. Areas considered climatically unsuitable for banana production and thus eliminated from further analysis were those with MAP < 900 mm (for dryland production), MAT < 16 degree Celsius, July means of daily minimum temperatures < 8 degree Celsius, the averages of the 12 monthly means of daily maximum temperatures < 22 degree Celsius and of minimum temperatures < 10 degree Celsius, as well as areas where the mean of the 12 monthly values of daily minimum RH was < 50 percent.