Comparison of Two Optimization Algorithms for Estimating Regional Winter Wheat Yield by Integrating MODIS Leaf Area Index and World Food Studies Model Liyan Tian1, Zhongxia Li2, Jianxi Huang1 ∗, Limin Wang3, Wei Su1, Chao Zhang1, and Junming Liu1 1College of Information and Electrical Engineering, China Agricultural University, Beijing, 100083, China 2Department of Geography, Texas A&M University, College Station, TX 77843-3147, USA 3Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China