拔节期追氮对冬小麦不同穗粒位籽粒特性的影响

以周麦18为材料,研究了底施纯氮120kg·hm~(-2)基础上拔节期不同追氮量对主茎穗和分蘖穗不同穗粒位籽粒特性的影响.结果表明:拔节期追氮,对主茎穗基部不孕小穗数、结实小穗率、不孕小穗率的影响达显著水平,对分蘖穗各性状的影响不显著.追氮处理下,结实小穗数和结实小穗率均高于不追氮处理.随追氮量增加,分蘖穗基部不孕小穗数增加,而主茎穗基部不孕小穗数低于不追氮处理.主茎穗及分蘖穗各穗位结实粒数和粒重均随小穗位升高呈先增后降二次曲线变化趋势,拐点分别位于9~10和6~9小穗位.拔节期追氮,促进了小穗粒数的增加,但二者之间并非正相关关系.主茎穗和分蘖穗不同粒位的粒数,以穗下部差异最大,尤以高追氮处理下差异显著.追氮对基部、顶部小穗第1、2粒位和中各小穗第3粒位粒重影响较大.主茎穗和分蘖穗第1、2粒位粒重显著高于第3粒位,而第1、2粒位粒重差异不显著.适量追氮增加了分蘖穗第3粒位粒重.本研究中,底施纯氮120kg·hm~(-2)基础上拔节期追氮100kg·hm~(-2)时,主茎穗及分蘖穗不同穗位与粒位的结实粒数、小穗重和单粒重均较高.

Effects of Nitrogen Top-dressing at Jointing Stage on Kernel Traits at Different Spikelets and Grain Positions in Winter Wheat

In order to study the effects of nitrogen top-dressing at jointing stage on kernel traits at different spikelets and grain positions in winter wheat,we applied 6levels of nitrogen fertilizer at jointing stage with base nitrogen 120kg·hm~(-2) during 2011 to 2012in Xun county.Zhoumai-18 which was the main cultivar in Henan province was chosen as the experimental material.We investigated the grain number and grain weight at different spikelets and grain position of main axis and tiller.The results showed that nitrogen top-dressing affected both sterile spikelet number at bottom and fertile and sterile spikelets rate significantly in main axis,while had none significant effects on tiller spike characteristics.Compared to none nitrogen topdressing,fertile spikelets per spike and fertile spikelets rate tended to be higher under nitrogen applying at joint stage.And with the nitrogen top-dressing level adding,sterile spikelet number at bottom of tiller increased,and sterile spikelet number at bottom of main axis showed lower.Quadratic curve equation could be used to describing the grain number and grain weight for the rising of spikelet position,and the inflection point was 9~(th) to 10~(th) spikelet position and 6~(th) to 9~(th) spikelet position,respectively.Nitrogen top-dressing at jointing stage increased the grain number per spikelet,but there was no positive correlation relationship.Grain number at different grain position of main axis and tiller tended to be quite different in lower spikelet position,and especially under higher nitrogen applying.Nitrogen top-dressing affected the 1~(st) and 2~(nd) grain in top and bottom spikelet position and the 3~(rd) grain in spike.The 1~(st) and 2~(nd) grain weight showed higher than the 3rd significantly,but the difference between the 1~(st) and 2~(nd) was not significant.Appropriate nitrogen top-dressing improved the 3rd grain weight in tiller spikelet.In this study,under the treatment of 100kg·hm~(-2) nitrogen top-dressing based with 120kg·hm~(-2),the grain number per spike and grain weight,spikelet weight were all higher both in spikes of main axis and tiller.