Cloning and Expression Analysis of Heat Shock Protein Gene ZmHSP90-1 in Maize Relationship between Distribution of 14C-assimilates and Kernel Abortion in Maize Programmed Cell Death during Abortion of Microspore in S-type Cytoplasmically Male-sterile Maize Differences between Maize and Wheat for Non-photochemical Quenching (qN) during Photosynthetic Induction Detection of Quantitative Trait Loci for Plant Height in Different Photoperiod Environments Using an Immortalized F2 Population in Maize