中文摘要：

[目的]研究河西制种基地玉米杂交种种子成熟度与种子活力的关系，确定高活力种子的适宜收获期，为种子企业躲避早秋霜冻提供依据。[方法]选择硬粒型先玉335、马齿型郑单958和吉祥1号3个杂交种制种田，授粉后每隔3—5 d采集果穗测定籽粒水分，实验室进行标准发芽和冷浸抗冷试验，测定种子发芽率和浸出液电导率，籽粒乳线发育按5级分类法记录：1=整个胚乳是液体状，无乳线；2=种子长度的25%充满硬化胚乳层，乳线出现在离种子顶部1/4处；3=种子长度的50%充满硬化胚乳层，乳线出现在种子1/2处；4=种子长度的3/4含硬化胚乳层，乳线下移到接近种子基部；5=整个种子是硬化的胚乳层，乳线消失。[结果]不同玉米杂交种、授粉后不同采收期对籽粒水分、脱水速率、种子发芽率和活力影响达到极显著水平，先玉335脱水早、脱水快，授粉后32 d时籽粒水分比郑单958、吉祥1号低10%—15%，授粉后32—75 d随着灌浆的进行果穗籽粒水分递减，平均生理脱水速率先玉335（0.70%/d）高于郑单958（0.62%/d）和吉祥1号（0.49%/d），籽粒水分每减少1%，先玉335、郑单958和吉祥1号百粒重依次增加0.73 g、0.50 g、0.29 g。不同采收期种子成熟度和种子活力有较大差异，籽粒水分为70%—40%，随着水分降低，种子发芽率增加、浸出液电导率减少，水分每减少1%，先玉335、郑单958和吉祥1号发芽率依次提高3.37%、2.76%、1.67%。随着灌浆时间推后，籽粒发芽率增加、电导率降低，但杂交种之间有一定差异，授粉后32 d 3个杂交种标准发芽率为30.0%—59.0%，6℃冷浸3 d发芽率为2.5%—36.9%，授粉47 d以后先玉335冷浸芽率与标准发芽率接近，而郑单958、吉祥1号冷浸发芽率始终明显低于标准发芽率，即种子抗低温能力大小为先玉335＞郑单958＞吉祥1号。种子发育过程中籽粒水分与乳线发育明显相?

英文摘要：

[Objective]The objective of this study was to clarify relationships between seed maturity and vigor, and to determine optimum harvest of maize seed with high vigor so as to provide references for seed enterprises to avoid early autumn frost, in Hexi in China.[Method]Samples for maize seeds were obtained at 3 to 5 days intervals after pollination to test seed moisture, standard germination-SG （7 days at 25℃）, and vigor, using cold test-CT （3 days at 6℃） and electrical conductivity-EC （three 50-seed samples, 24 hours inhibition at 25℃）, and milk line development was classified by a five-stage system, using three genotypes （hybrid XY335, ZD958 and JX1） during the crop seasons of 2013.[Result]Seed moisture and seed moisture-loss rate and germination and vigor were highly influenced by genotypes and days after pollination （DAP）. XY335 seed dehydrated early and quick, and seed moisture content was 10-15 percentage points lower in XY335 than that in ZD958 and JX1 at 32 DAP. During grain filling period from 32 to 72 DAP, seed moisture in ear decreased with time, average moisture-loss rate for XY335 was 0.70% per day that was higher than 0.62% per day in ZD958 and 0.49% per day in JX1, and 100-seed weight increased 0.73 g in XY335 and 0.50 g in ZD958 and 0.29 g in JX1 when seed moisture reduced one percentage point. Seed maturity and vigor at different days after pollination had a great difference, and seed quality values in terms of standard germination increased and electrical conductivity values decreased with seed moisture decreases from 70% to 40%, and the SG values increased by 3.37 percentage points in XY335 and 2.76 percentage points in ZD958 and 1.67 percentage points in JX1 as one percentage point reduction in seed moisture. With grain filling moving forward, the SG tended to increase and the EC to decrease but these changes were different across genotypes and DAP, and the SG ranged from 30% to 59% and the vigor at cold test from 2.5% to 36.9% at 32 DAP, and the seed germination values