Within-and between-population variations in seed and seedling traits of Juglans mandshurica

In order to quantify within-and between-population variation in seed and seedling traits of Juglans mandshurica and reveal the relationship among genetic and environmental variations and select elite families, samples of 50 J. mandshurica families from five natural populations in Liaoning Province, northeast China, were taken to measure seed and seedling traits. The results show that all seed traits varied significantly among families within the population, but only kernel weight and kernel rate showed significant variations among populations. Average values of single seed weight, length, width, lateral diameter, and average size, and kernel weight and rate were 10.1 g, 43.0 mm, 29.2 mm,28.1 mm, 33.4 mm, and 2.2 g and 22.5%, respectively. Significant variations were observed in seedling height and root collar diameter among families and interaction between families and blocks, but the block effects on height and root collar diameter were insignificant. Average values of height and root collar diameter were 94.0 cm and 8.7 mm, respectively. Family heritability of traits ranged from 0.6 gm(kernel weight) to 0.9 mm(seedling height). Correlation analysis showed a strong relationship among seed traits but a weak correlation between seed and seedling traits. Cluster analysis grouped the five natural populations of J. mandshurica into three significant clusters with different characteristics. The general combining ability analysis showed that most traits in one family(WD11) were higher, suggesting parental traits were excellent for selecting elite parent clones. Using the comprehensive evaluation method, five families with better seed traits and five families with better seedling traits were selected as elite materials with 10% selection rate. The genetic gains of these elite materials for seed weight, kernel weight, average seed size, kernel rate, seedling height, and root collar diameter were 13.1%, 10.3%, 4.1%, 2.4%, 29.7%, and 21.1%, respectively.