Abstract: This paper focused to study the filling theory on two-step-filling(TSF). The results showed that the TSF performed not only in hybrids but also in conventional varieties and this performance was operated by the processes of simultaneous step up filling(SSUF) and differential step up filling(DSUF) in vigor spikelets(VSs) and weak spikelets(WSs); the TSF would not be demonstrated clearly under the stronger SSUF without DSUF or with weaker DSUF, while the TSF would express very clearly under the opposite case. The strong SSUF associated with the earlier and faster grain filling and much more repartition so that it is helpful to improve grain plumpness and seed setting rate. This paper has given a proposed model on accumulation of photoproducts in spikelets. For the photosynthetic accumulations, the much stronger SSUF with the absence of the process of DSUF is the best character, the strong SSUF with effective DSUF is better one, but the weak SSUF with weaker DSUF or with worse DSUF should be avoided for the cultivation practices and the breeding programme.

Key words: differential step up filling, indica rice, simultaneous step up filling, two-step-filling

摘要： 选取50～90年代的代表品种以及不同类型的杂交稻，研究其灌浆理论。结果表明：两段灌浆乃水稻的共性所在，而强、弱势颖花的同步灌浆及弱势花的异步灌浆能力的差异决定该特性的表达。同步性强异步性弱，两段灌浆表现不明显；同步性弱异步性强，两段灌浆明显。同步性强表现灌浆起动早，速度快，强度大，物质撤退迅速，有利于提高结实率和籽粒充实度。文中提出籽粒物质积累模式，认为同步性很强，异步性丧失，极有利于物质积累；同步性较强，异步性较弱次之；同步性较弱，异步性可充分表达，易受环境条件的影响，不利于提高结实率和籽粒充实度；而同步性较弱，异步性表达受阻，物质积累少。栽培与育种上应尽量避免后两种情况。

关键词: 籼型水稻, 两段灌浆, 异步灌浆, 同步灌浆