成员判定是疏散星团研究中最关键的一步,成员判定的好坏直接影响对星团基本参数的估计.首次利用数据挖掘技术中的DBSCAN(Density-Based Spatial Clustering of Applications with Noise)聚类算法对疏散星团NGC 6791和M67(NGC 2682)分别...成员判定是疏散星团研究中最关键的一步,成员判定的好坏直接影响对星团基本参数的估计.首次利用数据挖掘技术中的DBSCAN(Density-Based Spatial Clustering of Applications with Noise)聚类算法对疏散星团NGC 6791和M67(NGC 2682)分别进行了成员判定,结果表明DBSCAN聚类算法能很有效地剔除场星污染.得到的NGC6791成员星的颜色-星等图上主序清晰并呈现明显的双重主序结构,这表明NGC 6791可能有更复杂的恒星形成与演化历史.对M67的分析表明出现了质量分层现象,并且星团的核心和外围两部分有明显的相对运动.对NGC 6791和M67的分析均表明DBSCAN聚类算法是一种有效的成员判定方法,有传统成员判定方法不具备的一些优点.展开更多
The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of...The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of genotypes into relative maturity groups (RMG). The aim of this study was to define stable genotypes for traits, such as days to flowering, days to maturity, and length of the reproductive period, and to classify them into RMG. For this purpose, 20 commercial soybean cultivars were evaluated in 12 environments distributed in the major producing regions of Brazil. Assessments according to the Eberhart and Russell method and the additive main effects and multiplicative interaction (AMMI) method were effective in the identification of stable genotypes and their classification into RMG. These methods can also be used collectively for this purpose. Our results showed that the AMMI method led to a better interpretation of genotype-environment interactions. Thus, RMG obtained on the basis of stable genotypes represented a good estimate of the relative maturity of soybean crops throughout Brazil. *Corresponding author.展开更多
文摘The stability of soybean genotypes is very important in breeding programs for not only the evaluation, selection, and production of cultivars but also the establishment of parameters required for the classification of genotypes into relative maturity groups (RMG). The aim of this study was to define stable genotypes for traits, such as days to flowering, days to maturity, and length of the reproductive period, and to classify them into RMG. For this purpose, 20 commercial soybean cultivars were evaluated in 12 environments distributed in the major producing regions of Brazil. Assessments according to the Eberhart and Russell method and the additive main effects and multiplicative interaction (AMMI) method were effective in the identification of stable genotypes and their classification into RMG. These methods can also be used collectively for this purpose. Our results showed that the AMMI method led to a better interpretation of genotype-environment interactions. Thus, RMG obtained on the basis of stable genotypes represented a good estimate of the relative maturity of soybean crops throughout Brazil. *Corresponding author.
