Grain-filling problem in 'super' rice.
Modern rice (Oryza sativa L.) cultivars, especially the newly bred 'super' rice, have numerous spikelets on a panicle with a large yield capacity. However, these cultivars often fail to achieve their high yield potential due to poor grain-filling of later-flowering inferior spikelets (in contrast to the earlier-flowering superior spikelets). Conventional thinking to explain the poor grain-filling is the consequence of carbon limitation. Recent studies, however, have shown that carbohydrate supply should not be the major problem because they have adequate sucrose at their initial grain-filling stage. The low activities of key enzymes in carbon metabolism may contribute to the poor grain-filling. Proper field practices, such as moderate soil drying during mid- and late grain-filling stages, could solve some problems in poor grain-filling. Further studies are needed by molecular approaches to investigate the signal transport, the hormonal action, the gene expressions, and the biochemical processes in inferior spikelets.
Yang
Jianchang
J
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, Jiangsu, China.
Zhang
Jianhua
J
D050260:Carbohydrate Metabolism; D035264:Flowers / Q000502:physiology; D009929:Organ Size; D012275:Oryza / Q000254:growth & development*; D012639:Seeds / Q000254:growth & development*; D012987:Soil; D012995:Solubility
D012987:Soil