以杂交粳稻常优5号为材料,设置未施氮肥处理(0N)、当地高产栽培(对照)、超高产栽培和氮肥高效利用栽培等4种栽培模式,观察其对水稻不同生育期根系形态生理和地上部生长的影响。结果表明,不同栽培模式下水稻产量差异极显著。超高产栽培与氮肥高效利用栽培两年的平均产量分别为12.29 t hm–2和9.62 t hm–2,平均分别较对照增产41.4%和10.7%。上述两种栽培模式的氮肥农学利用率(每kg施氮量增加的产量)分别较对照增加80.7%和76.8%,灌溉水利用效率分别较对照提高62.1%和32.3%。与对照相比,超高产栽培与氮肥高效利用栽培均增加了水稻地上部干物重、叶面积指数、根干重、根长,提高了粒叶比,改善了库源关系,并提高了根冠比与根系伤流量。同时也提高了灌浆期剑叶净光合速率、根系氧化力、根系总吸收表面积与根系活跃吸收表面积,生育中后期根系、叶片以及根系伤流液中的玉米素(Z)与玉米素核苷(ZR)含量、灌浆期籽粒中蔗糖合酶(SuSase)以及腺苷二磷酸葡萄糖焦磷酸化酶(AGPase)活性。这说明,通过栽培技术的集成与优化可以提高水稻灌浆期根系和地上部的生理活性,促进水稻高产与水分养分高效利用。
在稻麦两熟制条件下,以扬麦20为材料,通过基本苗和氮肥施用量、施用时期及比例的调控,建立不同产量水平群体,研究籽粒产量9000 kg hm–2群体钾素积累、分配与利用特性。结果表明,籽粒产量≥9000 kg hm–2(超高产)群体钾素吸收高峰期出现在拔节至开花期,吸收的钾素占一生吸收钾素的52%~68%;开花期和成熟期钾素积累量均极显著高于<9000 kg hm–2(高产)群体。成熟期叶片、茎鞘、颖壳+穗轴和籽粒钾素积累量与籽粒产量均呈极显著线性正相关;花后茎鞘钾素转运量与产量呈极显著线性正相关,颖壳+穗轴钾素转运量与产量呈极显著线性负相关。超高产群体开花期和成熟期钾素积累量分别为430~450 kg hm–2和366~408 kg hm–2;成熟期钾素积累量,茎鞘中最高,为244~269 kg hm–2,其次是叶片和颖壳+穗轴,分别为46~49 kg hm–2和40~46 kg hm–2,籽粒中仅为35~46 kg hm–2;花后茎鞘钾素转出量为46~52 kg hm–2,颖壳+穗轴钾素积累量为9~17 kg hm–2。超高产群体每100 kg籽粒的吸钾量需达4.57~4.87 kg,此时的钾素利用效率为20.56~22.02 kg kg–1,钾收获指数为0.095~0.112。
Improvement of yield in rice(Oryza sativa L.) is vital for ensuring food security in China. Both rice breeders and growers need an improved understanding of the relationship between yield and yield-related traits. New indica cultivars(53 in 2007 and 48 in 2008) were grown in Taoyuan,Yunnan province, to identify important components contributing to yield. Additionally, two standard indica rice cultivars with similar yield potentials, II You 107(a large-panicle type) and Xieyou 107(a heavy-panicle type), were planted in Taoyuan, Yunnan province and Nanjing,Jiangsu province, from 2006 to 2008 to evaluate the stability of yield and yield-related attributes.Growth duration(GD), leaf area index(LAI), panicles per m2(PN), and spikelets per m2(SM) were significantly and positively correlated with grain yield(GY) over all years. Sequential path analysis identified PN and panicle weight(PW) as important first-order traits that influenced grain yield. All direct effects were significant, as indicated by bootstrap analysis. Yield potential varied greatly across locations but not across years. Plant height(PH), days from heading to maturity(HM), and grain weight(GW) were stable traits that showed little variation across sites or years, whereas GD(mainly the pre-heading period, PHP) and PN varied significantly across locations. To achieve a yield of 15 t ha-1, a cultivar should have a PH of 110–125 cm, a long GD with HM of approximately 40 days, a PN of 300–400 m-2, and a GW of 29–31 mg.
