Qin Li, Wang Chenyu, Zhao Hong, Zhou Shenqi, Liu Kun, Liu Lijun
Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Co-Innovation Centre for Modern Production Technology of Grain Crops/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
Development Center of Science and Technology, Ministry of Agriculture and Rural Affairs, Beijing, 100176, China.
Sci Rep. 2025 Feb 3;15(1):4093. doi: 10.1038/s41598-025-88424-3.
Increasing spikelets differentiation, reducing their degradation and promoting big panicle formation are crucial approaches to increasing grain yield in rice. Straw incorporation and nitrogen (N) application have vital effects on rice yield, but the influence of incorporating wheat straw with N fertilizer ratio on spikelet differentiation, degeneration, and grain yield in rice is not clear. In this experiment, hybrid rice Fengyouxiangzhan (FY) and Yongyou 2640 (YY) were used as materials. Under the condition of total nitrogen application rate of 270 kg ha, the effects of local farmers' fertilizer practice (FP, basal fertilizer: tillering fertilizer: panicle fertilizer = 5: 1: 4) and improving basal fertilizer proportion (IP, basal fertilizer: tillering fertilizer: panicle fertilizer = 7: 1: 2) on the grain yield, branch and spikelet differentiation and degeneration of the above rice varieties were studied under the conditions of non-wheat straw returning (NR) and wheat straw full returning (WR). The 2-year (2020-2021) results in field trials showed that: (1) under NR, compared with FP, although the panicles per unit area were increased, the spikelet number per panicle, filled grains, and grain weight decreased to varying degrees, and finally the grain yield decreased significantly in IP. Under WR, although the filled grains and grain weight were decreased in IP treatment, the total spikelets (panicles per unit area × spikelet number per panicle) was increased significantly, and the grain yield was finally increased significantly compared with FP, with an increase of 6.85 ~ 7.08%. (2) There was a strong positive link between the total spikelets and grain yield, but a substantial negative relationship between the total spikelets and the number of filled grains and grain weight. (3) Straw treatment and nitrogen treatment mainly affected the spikelet number per panicle by affecting the differentiation and degeneration of secondary branches and spikelets. Under WR, IP increased the differentiation number of secondary spikelet in the middle and basal parts of FY by 22.0% and 30.9% with FP, respectively, but also increased the number and rate of secondary spikelet degeneration in the middle and basal parts. Under IP, compared with NR treatment, the differentiated number, degenerated number, surviving number, and degradation rate of the middle and basal parts of the secondary spikelets in the two varieties were increased in WR treatment. Overall, these results demonstrated that under WR, IP was beneficial to increase effective panicle numbers and the spikelet number per panicle. More secondary spikelet differentiation in the middle and basal parts per panicle was a main reason for increasing the spikelet number per panicle to increase grain yield under IP treatment.
增加小穗分化、减少其退化并促进大穗形成是提高水稻产量的关键途径。秸秆还田和施氮对水稻产量有重要影响，但小麦秸秆与氮肥配比对水稻小穗分化、退化及产量的影响尚不清楚。本试验以杂交水稻丰优香占（FY）和甬优2640（YY）为材料。在总施氮量为270 kg·ha的条件下，研究了当地农民施肥方式（FP，基肥∶分蘖肥∶穗肥 = 5∶1∶4）和提高基肥比例（IP，基肥∶分蘖肥∶穗肥 = 7∶1∶2）在不麦秸还田（NR）和麦秸全量还田（WR）条件下对上述水稻品种产量、枝梗和小穗分化及退化的影响。两年（2020—2021年）田间试验结果表明：（1）在NR条件下，与FP相比，IP虽然单位面积穗数增加，但每穗小穗数、实粒数和粒重均有不同程度下降，最终产量显著降低。在WR条件下，IP处理虽实粒数和粒重下降，但总小穗数（单位面积穗数×每穗小穗数）显著增加，最终产量较FP显著提高，增幅为6.85%～7.08%。（2）总小穗数与产量呈极显著正相关，与实粒数和粒重呈极显著负相关。（3）秸秆处理和施氮处理主要通过影响二次枝梗和小穗的分化与退化来影响每穗小穗数。在WR条件下，IP处理使FY品种中部和基部二次小穗分化数分别比FP增加22.0%和30.9%，但也增加了中部和基部二次小穗的退化数和退化率。在IP处理下，与NR处理相比，WR处理两个品种二次小穗中部和基部的分化数、退化数、存活数和退化率均增加。总体而言，这些结果表明，在WR条件下，IP有利于增加有效穗数和每穗小穗数。每穗中部和基部更多的二次小穗分化是IP处理下增加每穗小穗数从而提高产量的主要原因。
