高收获指数型超级稻茎鞘物质转运与抗倒性的关系及氮肥调控效应研究

Breeding and adoption of super rice cultivars with high harvest index is a feasible way to achieve high-yield and high-efficiency rice production. Previous studies showed that super rice cultivars with high harvest index (Guiliangyou 2 and Wuyou 308) had high reserve translocation but also good lodging resistance, indicating that reserve translocation and lodging resistance are well balanced in this cultivar. However, the mechanisms are not clear. Moreover, reserve translocation and lodging resistance depend not only on the genetic characters but also on the management practices. Inappropriate nitrogen management is one of the main reasons for rice lodging. However, there is no information available on the effects of nitrogen management (nitrogen application rates and strategies) on reserve translocation and lodging resistance in super rice cultivars with high harvest index. This program plans to carry out field experiments and laboratory analysis to determine the relationship between reserve translocation and lodging resistance and the effects of nitrogen application rates and strategies on reserve translocation and lodging resistance in Guiliangyou 2 and Wuyou 308. It is hoped that the findings from the program will help to understand the coordination mechanisms and the nitrogen regulation mechanisms on the relationship between reserve translocation and lodging resistance in super rice with high harvest index, and thus providing theoretical guidance for breeding super rice cultivars with high harvest index and establishing appropriate nitrogen management practices.

高收获指数型超级稻品种的选育和应用是实现水稻高产高效生产的一条有效途径。研究显示，已育成的高收获指数型超级稻品种（桂两优2号和五优308）虽然茎鞘物质转运多，但仍表现出了良好的抗倒性，实现了茎鞘物质转运与抗倒性的协调，但相关机制尚不清楚。此外，水稻茎鞘物质转运和抗倒性不仅与品种特性有关，还受栽培管理措施等的影响。氮肥施用不当是引起水稻倒伏的重要原因之一。但目前还未见有关氮肥管理（氮肥施用量和氮肥运筹）对高收获指数型超级稻品种茎鞘物质转运和抗倒性影响的报道。据此，本项目拟以高收获指数型超级稻品种桂两优2号和五优308为对象，通过大田试验和室内分析，研究其茎鞘物质转运与抗倒性的关系及氮肥施用量和氮肥运筹对其茎鞘物质转运和抗倒性的影响，以期揭示高收获指数型超级稻茎鞘物质转运与抗倒性关系的协调机制及氮肥调控机制，进而为高收获指数型超级稻品种的选育及配套氮肥管理技术的制定提供理论依据。

高收获指数型超级稻品种的选育和应用是实现水稻高产高效生产的一条有效途径。本项目通过4年（2018-2021）大田试验，研究了（1）高收获指数型超级稻品种桂两优2号和高干物质生产型超级稻品种Y两优1号（对照）的茎鞘物质转运特点和抗倒伏特性；（2）施氮量（150和225 kg N hm-2）和氮肥运筹（基肥:分蘖肥:基肥=6:3:1、5:3:2和4:3:3）对高收获指数型超级稻品种桂两优2号抗倒伏特性的影响。结果显示：（1）桂两优2号和Y两优1号的茎鞘物质转运量和转运率均随生态条件（地点和年份）变化而呈现出不同的变化，抽穗前后干物质生产量的比值是调控水稻茎鞘物质转运的重要因子；（2）桂两优2号的植株抗折力与Y两优1号无显著差异，但其株高和植株鲜重均显著低于Y两优1号，进而促使其倒伏指数也显著低于Y两优1号。桂两优2号和Y两优1号的倒伏指数均存在显著的年际间差异，且抽穗前干物质生产量大的年份茎鞘物质储藏量高，其植株的抗折力和抗倒性也越高，表明促进抽穗前生长是提高水稻抗倒性的有效途径；（3）增施氮肥导致了桂两优2号的植株鲜重显著增加、植株抗折力显著下降，进而促使其倒伏指数显著增加。氮肥运筹对桂两优2号抗倒伏指数的影响不显著。上述研究结果可为水稻抗倒伏栽培技术的制定提供理论依据。项目公开发表第一标注论文6篇（其中SCI论文4篇），申请实用新型专利1项（一种鉴定水稻群体抗倒伏性能的装置），培养中青年学术带头人1名（农业农村部农业科研杰出人才）、研究生5名（其中毕业硕士研究生2名、在读博士研究生1名、硕士研究生2名）。