稻茬小麦氮高效品种产量构成和群体质量特征

在稻麦两熟条件下,将2016—2017和2017—2018年江苏扬州参试的24个和江苏睢宁参试的23个小麦品种按氮肥表观利用率(NUR)划分为高效(NUR≥50%)、中效(NUR 40%～50%)和低效(NUR≤40%)品种类型,比较其产量、产量构成因素和群体质量指标的差异,为稻茬小麦品种选用和大面积高产高效生产提供参考。结果表明,两年度在扬州均表现出高效的品种为扬麦25和宁麦21,在睢宁为淮麦35。扬州和睢宁氮高效品种产量分别高于6500 kg hm^-2和7000 kg hm^-2,均显著高于其他类型。与氮中效和氮低效品种相比,氮高效品种具有较高的穗数,穗粒数和千粒重品种类型间差异不显著。不同品种间产量和穗数与NUR均呈线性正相关。氮高效品种具有较高的孕穗期和开花期茎蘖数,分蘖成穗率,乳熟期叶面积指数,孕穗期、开花期和成熟期干物质积累量,花后干物质积累量和成熟期各营养器官干物质积累量。不同氮效率品种类型间花前干物质转运量和收获指数差异不显著。相关性分析表明,两地不同品种类型间孕穗期和开花期茎蘖数、乳熟期LAI、主要生育时期干物质积累量、花后和...

Characteristics of yield components and population quality in high-nitrogen- utilization wheat cultivars

In the rice-wheat rotation system, 24 and 23 wheat cultivars were separately planted in Yangzhou and Suining of Jiangsu province in 2016-2017 and 2017-2018. According to nitrogen utilization rate (NUR), these cultivars were clustered into three groups, i.e., NUR-H (NUR ≥ 50%), NUR-M (NUR 40%-50%), and NUR-L (NUR ≤ 40%), to identify the differences in grain yield, yield components, and population quality, which would provide a reference for cultivar selection for high-yield and high-efficiency in wheat production. Yangmai 25 and Ningmai 21 in Yangzhou and Huaimai 35 in Suining showed NUR-H phenotypes in consecutive two years. Grain yield of the NUR-H cultivars was more than 6500 kg hm ^-2 in Yangzhou and 7000 kg hm ^-2 in Suining, which were significantly higher than those of NUR-M and NUR-L groups. NUR-H group had more spikes, and it grains per spike and 1000-grain weight were not significantly different from those of the other groups. Grain yield and spikes number were significantly positively correlated with NUR among different cultivars. More stem and tiller number, higher percentage of fertile tillers and higher leaf area index (LAI) at the milk-ripening stage were shown in the NUR-H group. A higher dry matter accumulation at stages of booting, anthesis, and maturity, after anthesis, and in the vegetative organs at maturity were found in the NUR-H group. However, there were no differences in dry matter remobilization and harvest index among different cultivars. Number of stems and tillers at booting and anthesis, LAI at the milk-ripe stage, and dry matter accumulation at each stage after anthesis, and in the vegetative organs at maturity were significantly positively correlated with NUR in the all cultivar in two sites. A vigorous tillering capacity at the early growing phase and a higher LAI and photosynthetic production at the late growth stages could be observed in NUR-H cultivars, resulting in more photosynthate for grain-filling. Furthermore, the critical parameters of cultivar screening for high-yield and high-efficiency in wheat following rice were proposed, that is 16,000-20,000 kg hm ^-2 dry matter accumulation at maturity and 4100-6700 kg hm ^-2 dry matter accumulation after anthesis.