Abstract: 【Objective】 The changes in yield and agronomic traits of broomcorn millet cultivars were analyzed in the national cultivars regional adaptation tests made in recent 17 years. The progress of broomcorn millet improvement and the capacity of the breeding institutions in China were investigated, aimed to provide information for further genetic improvement of broomcorn millet in China. 【Method】 The multivariate regression analysis, correlation analysis and cluster analysis were employed. The phenotypical variation of the broomcorn millet cultivars in the national regional adaptation tests were analyzed from the year 1998 to 2014. The differences in traits among the cultivars that bred by different breeding institutions were compared. 【Result】 The traits altered significantly among the years from 1998 to 2014 for broomcorn millet cultivars. Yield and grain weight per plant of non-waxy millet, and the yield, grain weight and panicle length of waxy millet constantly increased over the years. In the past 17 years, the yield of non-waxy and waxy millet increased by 50% and 21%, respectively. The grain weight per plant was increased by 90% and 7%, respectively. Panicle length was increased by 19% and 29%, respectively. There were no significant alteration in growing duration, plant height, node number and grain weight. Seventeen breeding institutions from Heilongjiang, Jilin, Liaoning, Inner Mongolia, Hebei, Shanxi, Shaanxi, Gansu and Ningxia provided 65 cultivars in total for the national cultivar regional adaptation test. Of which, seven institutions provided both non-waxy and waxy cultivars, two institutions provided only the non-waxy cultivars, and eight institutions provided only the waxy cultivars. The breeding institutions from Inner Mongolia, Gansu and Ningxia contributed 55.4% of the cultivars in total. In the latest 6 years, the cultivars from these 3 regions showed excellent performance, thus the breeding institutions in these regions are the backbone of broomcorn millet breeding in China. Multivariate regression analysis on yield and agronomic traits showed that the growing duration, node number and grain weight per plant contributed 82.8% of the yield variation for the non-waxy millet, whereas in the waxy millet, the node number and grain weight per plant together determined 78.6% of the yield variation. The correlation analysis showed that in both the non-waxy and waxy millet, panicle length and grain weight per plant were significantly correlated with yield per plant, however, the correlation among other traits were different between non-waxy millet and waxy millet. The cluster analysis showed that the non-waxy cultivars were grouped into 2 categories, whereas it could be divided into 3 categories for the waxy cultivars. 【Conclusion】 The yield of non-waxy and waxy millet in China were increased steadily from 1998 to 2014, which indicated that the breeding ability of the institutions in China has increased. However, the breeding method is relatively simple and the diversity of the breeding method is low. Broomcorn millet breeders ignored the importance of the yield related traits and quality traits. As for the broomcorn millet breeding direction in the future, the cultivars with high yield, high quality, good palatability, good cooking quality, high resistant starch content, strong resistance to shattering and good adaptability for mechanized cultivation should be developed. Multiple breeding methods including the traditional breeding methods such as hybrid breeding, distant hybridization, mutation breeding, doubled haploid and polyploidy breeding technology, introducing the methodology of genome research and molecular breeding, and combining traditional breeding with modern biotechnology are the most important strategy for improving the breeding technology of broomcorn millet.

Key words: broomcorn millet, regional adaptation test, yield, agronomic traits, cultivar improvement