Year-Round Cultivation of Sweet Sorghum [Sorghum bicolor (L.) Moench] through a Combination of Seed and Ratoon Cropping in Indonesian Savanna

We studied the year-round cultivation of sweet sorghum, which is a raw material for the fermentation of monosodium glutamate, in East Java, Indonesia. In this savanna area, each year comprises 2 seasons-dry (April-September) and rainy (October-March). Seed crops were sown almost every month for 1 yr, and each seed cropping was followed by a ratoon cropping after the seed crop harvest. The stem-related traits of plants from different sowing or ratooning dates were studied at around 17 weeks after sowing or ratooning. For both plants derived from seed and ratoon, better crop establishment was observed when cultivation was commenced during the rainy season than during the dry season. Although sowing was undertaken each week in August and September during the most severe dry period, germination rate was very low (or zero) and even the germinated plants died within a short time. In contrast, ratoon cropping was started and plants were grown until harvest. In East Java, it is considered possible to produce sweet sorghum throughout the year, mainly by sowing, but also partially by ratooning during the most severe drought period of the dry season.