遮阴和种植密度对东北春玉米穗部发育和植株生产力的影响

探讨遮阴对玉米穗部特性的影响及其产量效应,可以为应对气候变化与密植栽培条件下的玉米品种选育和高产栽培提供参考依据.本研究选用2个品种(紧凑型‘中单909’、平展型‘内单4’)和2个种植密度(4.5、9.0万株·hm^-2),在吉林省公主岭市开展田间遮阴试验,设置遮阴(遮阴度65%,小喇叭口期-成熟期)和不遮阴(对照)2个处理,研究遮阴和种植密度对不同株型玉米的穗部发育和植株生产力的影响.结果表明: 遮阴显著影响春玉米雌穗发育,造成散粉和吐丝期推迟,导致散粉吐丝间隔期延长3～15 d;遮阴显著降低春玉米干物质积累,籽粒产量下降50%以上(50.8%～87.0%);密植条件下春玉米穗部特性和产量性能受遮阴的影响显著高于稀植栽培;不同玉米品种相比,紧凑型品种的穗部特性和产量受遮阴和种植密度的影响低于平展型品种,紧凑型品种对生态环境变化的适应性较强,耐阴性和耐密性表现出一致性.

Effects of shading and plant density on ear development and plant productivity of spring maize in Northeast China

It is important to investigate the effects of shading on maize ear characteristics and yield, which can provide references to variety breeding and agronomic technique improvement for coping with climate change and dense planting. An experiment was carried out with two varieties (compact type hybrid ZD909, flat type hybrid ND4) and two planting densities (45000 and 90000 plants·hm^-2) at Gongzhuling City, Jilin Province. Two treatments were conducted for each variety and planting density, including shading (with a shading degree of 65% from small bell mouth stage to mature stage) and no shading treatment (CK). The results showed that shading affected maize ear development significantly. Shading delayed maize anthesis and silking stages, especially prolonging the length of anthesis-silking interval by 3-15 days compared with the CK. Moreover, shading decreased dry matter accumulation of spring maize significantly, leading to more than 50% (50.8%-87.0%) of reduction in grain yield. The negative effects of shading on ear characteristics and yield of spring maize with dense planting was greater than that with sparse planting. The variety with a dense plant type achieved fewer effects on ear characteristics and grain yield than the variety with a sparse plant type under shading and dense planting. The variety with a dense plant type had strong adaptability to ecological environment change and the consistency in density-tolerance and shade-tolerance.