水稻甬优12产量13.5t hm~(–2)以上超高产群体的生育特征

以籼粳交超级稻甬优12为试材、四叶一心期带蘖小苗移栽,超稀植(12.45×104穴hm–2)栽培,对高产(10.5~12.0 t hm–2)、更高产(12.0~13.5 t hm–2)、超高产(13.5 t hm–2)3个产量群体的产量及其结构、茎蘖动态、叶面积动态及干物质的积累与运转等进行了系统比较研究。结果表明,产量由高产(10.5~12.0 t hm–2)到更高产(12.0~13.5 t hm–2)再到超高产(13.5 t hm–2),群体的颖花量不断提高,结实率和千粒重略微下降。与高产和更高产群体相比,超高产群体茎蘖数起点较高,在有效分蘖临界叶龄期及时够苗,至拔节期群体茎蘖数稳步增长,达高峰苗,此后群体茎蘖数平缓下降,成穗率近60%;群体叶面积指数生育前期较小,最大值出现在孕穗期,为9.17,此后平缓下降,成熟期在4.0以上;群体干物质积累量在拔节期略低,此后各生育时期均升高,抽穗期为14.38 t hm–2,抽穗至成熟期为9.73 t hm–2,成熟期为24.11 t hm–2;群体根系干重、根冠比及单茎伤流强度在后期(抽穗至成熟期)均较高。

Population Characteristics for Super-High Yielding Hybrid Rice Yongyou 12 (>13.5 t ha-1)

Using indica-japonica super rice Yongyou 12, by transplanting seedlings with tillers at the age of four leaves with one leaf bud and applying super sparse cultivation technology, we compared and studied grain yield and its components, tiller dynamic, leaf area dynamic and accumulation dynamic of dry matter in three types of populations (High yield: 10.5–12.0 t ha^-1; Higher yield: 12.0–13.5 t ha^-1; Super-high yield: >13.5 t ha^-1). The results showed that super-high yielding rice had more population spikelets, and slightly lower seed-setting rate and 1000-grain weight than high yielding and higher yielding rice. Compared with high yielding and higher yielding rice, super-high yielding rice showed more number of stems and tillers at transplanting stage and achieved the expected number of stems and tillers at the critical leaf-age for productive tillers. During jointing stage the number of stems and tillers increased steadily and up to the maximum with a panicle rate of nearly 60%. The leaf area index of super-high yielding rice was relatively smaller at the early stage and the maximum of 9.17 at booting stage, and then slowly declined to more than 4.0 at maturity; The dry matter weight was relatively smaller at jointing stage and then the highest at each phase of the super-high yielding rice, which was 14.38 t ha^-1 at heading stage, 9.73 t ha^-1 from heading to maturity stage, and 24.11 t ha^-1 at maturity stage. The root dry weight, ratio of root to shoot and root bleeding intensity per stem of the super-high yielding rice population were all the highest from heading to maturity stages.