甬优籼粳杂交稻作再生稻种植的再生特性及产量形成分析

为探究甬优籼粳杂交稻作再生稻种植时的再生特性及产量形成特点，以生产上应用广泛的甬优籼粳杂交稻品种甬优1540和甬优4949为试验材料、籼型杂交稻品种隆两优534为对照材料作再生稻种植进行了田间试验。结果显示：籼粳杂交稻和籼型杂交稻2个类型品种的再生特性存在显著差异；籼粳杂交稻甬优1540和甬优4949的优势再生节位为低节位的倒5节和倒4节，2个节位的再生苗有效穗占比之和分别为81.9%和68.9%，产量贡献率之和分别为89.6%和72.5%；2个节位再生稻的穗长、每穗粒数显著高于倒3节和倒2节，并呈现出从下往上节位逐步变小的趋势；而籼型杂交稻品种隆两优534的优势再生节位则是高节位的倒2节和倒3节，2个节位的有效穗占比和产量贡献率之和分别为71.5%和72.5%；甬优4949头季稻收割后1~7 d内的再生苗的成穗率、有效穗占比和产量贡献率分别为89.4%、74.6%和79.2%，均显著高于收割后8~12 d和12 d以上的再生苗；甬优1540和甬优4949再生稻的穗长、每穗粒数均要显著大于隆两优534，产量分别增产21.6%和17.3%。结果表明甬优籼粳杂交稻的低节位强再生力和再生苗穗大粒多的再生特性是其作再生稻种植时易获得高产的主要因素。

Ratoon characteristics and yield formation of Yongyou indica-japonica hybrid rice as ratoon rice

Field experiments were conducted on the cultivation of ratoon rice using the widely used Yongyou indica-japonica hybrid rice varieties Yongyou 1540 and Yongyou 4949 as experimental materials and the indica-hybrid rice variety Longliangyou 534 as control materials to study the ratoon characteristics and yield formation of Yongyou indica-japonica hybrid rice planted as ratoon rice. The results showed that there are significant differences in the ratoon characteristics between indica-japonica hybrid rice and indica- hybrid rice. The dominant regenerated nodes of the indica-japonica hybrid rice Yongyou 1540 and Yongyou 4949 were the 4th and 5th nodes from top at the lower nodes， which produced a sum of 81.9% and 68.9% of effective panicles with 89.6% and 72.5% of the yield contribution in YongYou 1540 and YongYou 4949， respectively. The panicle length and the number of grains per panicle of these two nodes were significantly higher than that of the 2nd and 3rd nodes from top， showing a decreasing trend from the bottom to the top. The 2nd and 3rd nodes from top at the higher nodes of the Longliangyou 534 were dominant， producing 71.5% of effective panicles with 72.5% of the yield contribution. The spike rate， ratios of effective panicle and yield contribution of were 89.4%， 74.6% and 79.2% for regenerated seedlings of YongYou 4949 within 1-7 d after the first harvesting， significantly higher than those of regenerated seedlings within 8-12 d and 12 d above after the first harvesting. The panicle length and the number of grains per panicle in regenerated seedlings of Yongyou 1540 and Yongyou 4949 were significantly higher than those of Longliangyou 534， with yield increase of 21.6% and 17.3%， respectively. It is indicated that the strong regeneration ability of the low nodes， long panicles， and large number of grains per panicle in regenerated seedlings of Yongyou indica-japonica hybrid rice are the key factors that make it easy to achieve high yield when planted as ratoon rice.