close breeding的用法和样例：
例句
- Research progress on cross breeding of Chinese fir was summarized in this paper and the primary insufficiency was analyzed.
摘要概述了我国杉木杂交育种研究进展，分析了杉木杂交育种存在的主要问题及其对策。 - The index of drought resistance lies in yield increase and drought resistance.The hybrid breeding is the main measure for mungbean breeding.
抗旱指数是抗旱性和丰产性的有机结合，杂交育种是提高丰产性的关键。
