覆砂厚度对玉米半粒种子发芽特性的影响*

 为了加快玉米品质育种进程，在作物育种中往往将种子横切为两半，用带胚的半粒种子进行繁殖，不带胚的半粒种子用于品质分析，便于优质品种选育。研究以3个玉米品种为材料，将部分种子横切，以整粒玉米种子及半粒玉米种子不覆砂分别为对照1（CK ₁）和对照2（CK₂），对半粒种子分别覆砂1cm，2cm，3cm，4cm，进行发芽试验，测定发芽势、发芽率、发芽指数、活力指数、发芽速率、峰值、平均发芽率、发芽值等发芽特性，研究覆砂厚度对半粒玉米种子发芽特性的影响。结果表明半粒玉米种子不覆砂的发芽势、发芽率、发芽指数、峰值、平均发芽率、发芽值最高；半粒玉米种子覆砂1cm的各项发芽特性与对照差异不显著。覆砂3cm以上，发芽特性明显降低。说明采用玉米半粒种子进行繁殖是可行的，但为了保证出苗率，覆砂不宜过厚。

Effect of Sand Layer Thickness on Seed Germination of Maize Half seed

In crop quality breeding，the seed is often cut into two halves.One part with embryo is used to reproduce new seeds，while the other part without embryo is used to analyze quality parameters.Three different maize varieties were used to test seed germination characteristics.A part of seeds of each variety were cut into halves along sidle.In the study，the whole seeds was taken as CK ₁，the half seeds without sand cover as CK₂ and the other half seeds vere covered with the 1cm，2cm，3cm and 4cm thick layers of sand，respectively.The seeds germination characteristics such as germination energy，germination rate，germination index，vigor index，germination speed，maximum value，and average germination rate and germination value were tested.Then the effect of different sand layer thickness was studied on seed germination of maize half seed.The result indicated that the germination energy，germination rate，germination index，maximum value，average germination rate and germination value of maize half seeds without sand covering were the highest.There was no obvious difference of germination characteristics between the materials covered with 1cm thick sand and CK.When the half seeds were covered with above 3cm thick layers of sand，the germination characteristics decreased clearly.So it is feasible to use the half seeds to reproduce new seeds，but the sand shouldnt be covered too deep to ensure the rate of emergence.