Pepper (Capsicum annum and Capsicum frutescens) is thought to originate from tropical America. Most of the peppers grown belong to C. annum but the small, pungent peppers belong to C. frutescens. Present world production is about 19 million tons fresh fruit from 1.5 million ha.(FAOSTAT, 2001).
Pepper thrives in climates with growing season temperatures in the range of 18 to 27°C during the day and 15 to 18° C during the night. Lower night temperatures result in greater branching and more flowers; warmer night temperatures induce earlier flowering and this effect is more pronounced as light intensity increases.
The crop is grown extensively under rainfed conditions and high yields are obtained with rainfall of 600 to 1250 mm, well-distributed over the growing season. Heavy rainfall during the flowering period causes flower shedding and poor fruit setting, and during the ripening period rotting of fruits.
Light-textured soils with adequate water holding capacity and drainage are preferred. Optimum pH is 5.5 to 7.0 and acid soils require liming. Waterlogging, even for short periods, causes leaf shedding. Fertilizer requirements are 100 to 170 kg/ha N, 25 to 50 kg/ha P and 550 to 100 kg/ha K.
The crop is moderately sensitive to soil salinity, except in the seedling stage when it is more sensitive. Yield decrease at different levels of ECe is: 0% at ECe 1.5 mmhos/cm, 10% at 2.2, 25% at 3.3, 50% at 5.1 and 100% at ECe 8.5 mmhos/cm.
Seeds are sown in nursery beds which in the cooler climates are sometimes enclosed and heated since soil temperatures in the range of 20 to 24°C are considered optimum for germination. Seedlings of 10 to 20 cm height are transplanted in the field after 25 to 35 days. The length of the total growing period varies with climate and variety but in general it takes 120 to 150 days from sowing to the latest harvest. Prior to transplanting, the seedlings raised in enclosed and heated nurseries are hardened by increased ventilation. The plants are sometimes topped 10 days before transplanting to encourage branching. Plant spacing is 0.4 to 0.6 m x 0.9 m. For production of fruits for canning, closer spacings are sometimes used. Flowering starts 1 to 2 months after transplanting with first picking of green peppers 1 month later. Thereafter, ripe, red peppers are picked at 1 to 2 week intervals for up to 3 months. Ripe chillies are semi-dried for 3 to 15 days, with the final weight being about 25 percent of the fresh fruit weight.
The graph below depicts the crop stages of pepper, and the table summarises the main crop coefficients used for water management.