1. State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, Center of Bioinformatics, College of Life Sciences, Northwest A&F University , Yangling, Shaanxi 712100 , China
2. Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University , Yangling, Shaanxi 712100 , China
3. Institute for Genomic Diversity, Cornell University , Ithaca, NY 14853 , USA
4. School of Computer Software, College of Intelligence and Computing, Tianjin University , Tianjin 300072 , China