|
|
|
African Crops Networks |
|
NGICA (Cowpea) |
|
Other Networks |
|
Plant Protection Network, IAPPS |
|
Quick Info Links |
|
Online Journals |
|
Electronic Journal of Biotechnology |
|
African Journal of Biotechnology |
|
Free Access Portals |
|
AGORA: 400 Journals |
|
Crop Databases |
|
Crop Specific DBs |
|
Genetic Maps |
|
Bibliographic Database |
|
Search Facilities |
|
User Information |
|
Implications of the sweetness of drought for ratooning cereals, in particular cereals with ‘stay-green’ W.A.J. de Milliano In the semi-arid regions of Africa, drought is an uncertainty during the rainy periods but a certainty during the periods between unimodal or bimodal rainfall. Drought is feared for its effect in reducing the grain yield of rainfed cereals. However, rainfed sorghum displays various drought-surviving traits that have value to the farmer. This research focused on the traits manifested by sorghum, pearl millet, finger millet and maize during the dry periods between November 2002 and November 2004 in the fields at Ukulinga Farm (29º40'S, 30º25'E, 785 m alt.), Pietermaritzburg, South Africa. Four crop cycles were completed in this period and two periods of over 6 months of severe drought were endured. Sorghum had repeated ratooning ability and year-round stay-green in the field. Pearl millet, finger millet and maize displayed various ratooning abilities, no stay-green, and did not survive the cool, dry season. Heads of ratooned sorghum that became affected by sugary disease, caused by Claviceps africana, exuded much sugary liquid. The sorghum open-pollinated variety (OPV) Macia and the pearl millet OPV PMV3 were used as controls to study the Brix levels of stem juices under irrigated and rainfed conditions. The results showed that during drought, sugar levels increase in the stem juices. Sugar levels become particularly high in a ratoon or in plants with stay-green. The findings indicate that stay-green cereals with drought tolerance such as sorghum will have high Brix levels during a drought period and likely will have high feed value. It follows that, for example, a pearl millet or maize variety with stay-green is expected to have a much higher sugar level than a variety that becomes necrotic after harvest. Presently, stay-green is only a selection criterion in sorghum breeding. However, ergot in sorghum and stay-green in other cereals may be important selection criteria for fodder quality and quantity. Most importantly, it was found that rainfed sorghum with equal biomass might have higher sugar levels than an irrigated crop. |