PREFACE
ABSTRACT
CHAPTER 1 Introduction
1.1 Background
1.2 Literature review
1.3 Methodology
1.4 Organization
CHAPTER 2 The contribution of seed variety to rice yield increases
2.1 Rice yield changes in China
2.2 Evolution in rice seed varieties in China
2.3 Specification for rice yield model
2.4 Model estimation
2.5 Empirical results
2.6 Summary
CHAPTER 3 The contribution of seed variety to wheat yield increases
3.1 Wheat yield changes in China
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