高粱种子对萌发温度的响应分析与耐低温萌发能力鉴定

萌发期的低温是限制种子萌发的一个重要非生物胁迫因子,高粱种子耐低温萌发能力是保证高粱出苗整齐、建立良好群体的基础,因此研究高粱品种对不同萌发温度的响应特征具有重要的理论和应用价值。本试验用来源于不同地区的30份高粱品种,在25℃、20℃、16℃和12℃人工气候箱中进行萌发试验,测定不同温度下高粱品种的发芽势、发芽率、芽长、根长、芽重、根重等萌发指标,分析不同高粱品种的萌发差异;通过主成分分析和聚类分析,对不同高粱品种萌发期耐低温特性鉴定和分类,结果表明,随着萌发温度的降低,高粱芽和根的生长均受到抑制,但根与芽的重量和长度比均增加,说明萌发过程中芽比根对低温更加敏感。30个高粱品种的6个萌发指标相对值之间存在一定相关性。主成分分析表明,相对芽长、相对根长和相对发芽率分别在3个主成分中载荷较大,可作为高粱萌发期耐低温的主要鉴定指标。30个高粱品种按萌发期耐低温能力可分为四大类,辽粘3号极不耐低温,济粱1号等18个品种对低温敏感,冀酿1号等5个品种对低温不敏感,赤杂101等6个品种对萌发期低温具有较强的耐性。

Responses of sorghum hybrids to germination temperatures and identification of low temperature resistance

Low temperature during germination is an important abiotic stress factor limiting seed germination. Sorghum seeds with high germination capacity at low temperature are conducive to the emergence and establishment of a good population. Therefore, studying the response characteristics of sorghum hybrids to different germination temperatures is of great theoretical and practical value. Thirty sorghum hybrids from different regions of China were germinated in the artificial climate chamber, at 25°C, 20°C, 16°C, or 12°C to measure germination potential, germination percent, bud length, root length, bud weight and root weight. Sorghum hybrids were identified and classified according to low temperature resistance during the germination based on principal component analysis (PCA) and clustering analysis. With a decrease in germination temperature, the growth of both buds and roots were inhibited, but the ratio of roots to buds in both weight and length increased, indicating that buds were more sensitive to low temperature during germination than roots. The relative values of six germination indicators of the thirty sorghum hybrids were correlated between each other. The PCA results showed that relative bud length, relative root length and relative germination percent could be used to evaluate the sorghum germination capacity under low temperatures because these indicators had the largest loads in the three principal components, respectively. According to the low temperature tolerance ability of the 30 sorghum hybrids were divided into four categories: Liaonian 3 was extremely sensitive to low temperature; eighteen hybrids, such as Jiliang 1, were sensitive to low temperature; five hybrids, such as Jiniang 1, were insensitive to low temperature, and six hybrids, such as Chiza 101 had a strong low temperature tolerance during the germination.