不同玉米品种子粒硬度差异及与含水率的关系

在北京和河南新乡两个生态区，通过设置不同品种和播期试验，利用手持便携式推拉力计测定玉米子粒不同含水率条件下胚、胚乳和顶部的硬度，明确玉米子粒脱水过程中硬度的变化规律，分析玉米子粒含水率与硬度之间的关系。结果表明，手持便携式推拉力计可以测定不同玉米品种及含水条件下子粒顶部、胚和胚乳的穿刺强度，用来表征子粒的硬度。子粒胚乳的硬度最高，其次是顶部，胚的硬度最低。子粒硬度随着含水率的降低逐渐升高，胚的硬度对含水率的变化最为敏感，顶部硬度对含水率的变化最不敏感。不同品种之间，子粒胚乳硬度对含水率的响应不同。生产中可通过测定胚乳硬度进行适宜粒收品种的筛选和适宜收获期的确定。

Kernel Hardness of Different Maize Cultivars and the Relationship between Kernel Hardness and Moisture Content

This study located in two ecological planting areas, and set different cultivars and sowing dates experiments. The hardness of embryo, endosperm and top of the kernel were measured using the hand portable push-pull meter under different moisture content condition. To determine the change of hardness during the dehydration process of maize kernel, and to analyze the relationship between kernel moisture content and hardness.The results show that hand portable push-pull meter can measure puncture strength of kernel embryo, endosperm and top of different maize cultivar under moisture content variation. The penetration strength can be used to characterize the hardness of the kernel. The endosperm of kernel had the highest hardness, followed by the top, and the hardness of embryo is the lowest. Kernel hardness increased as the decreasing of moisture content. The hardness of embryo was the most sensitive to moisture content changing, however, the hardness of top was the least sensitive to moisture content changing. The response of endosperm hardness to moisture content is different among different cultivar. The selection of suitable cultivars and the determination of optimal harvesting period can be carried out by the hardness of the endosperm in maize production.