Abstract China, origin of mulberry, has rich genetic resources usually. High expense, limited space and wavering environment of usually conservation in vivo poses dangerous situation for mulberry. The concept of core collection could takes priority for conservation of mulberry. In this study, 560 accessions were used with 40 morphological descriptors and stratified sampling strategies for a core collection. The core collection consisted of 28 accessions, accounting for 5% of the whole collection. The core collection included seven accessions belonging to Morus alba, one accession belonging to M. alba var. macrophylla, four accessions belonging to M. atropurprea, one accession belonging to M. nigra, three accessions belonging to M. australis, seven accessions belonging to M. multicaulis, two accessions belonging to M. wittorum and three accessions belonging to M. bombycis. The quality of core collection exceeded the evaluation criteria and could be a prioritized collection for high efficient and long-term conservation for mulberry.

The fluid state on a sieve tray will change when the towers tilt under wind loads. A computational fluid dynamics (CFD) model was used to predict the flow patters and hydraulics on the tray under different inclinations. The gas and liquid phases are modelled with the volume-of-fluid (VOF) framework as two inmiscible phases. Several three-dimensional transient simulations were carried out for a 0.38m diameter tray with varying liquid weir loads and inclined angles. The clear liquid height determined from these simulations is in reasonable agreement with experimental measurements carried out for air-water in a round tray of the same dimensions. The simulation results show that, compared with the horizontal tray, the circulation area is bigger when the liquid flow and inclination direction of the tray are the same, but when they are opposite the circulation area is smaller. The percentage of circulation area to the tray area can obviously be decreased, along with increasing liquid weir loads. It is concluded that CFD can be used for the prediction of liquid flow on sieve trays under different inclinations