Various approaches have been used to improve the performance of adapted indigenous stock, including cross-breeding and upgrading through back-crossing with improved breeds, and within-line selection.
已有多种方法被用于提高地方良种的性能，包括杂交育种，以及通过与良种的回交和品系内选育进行的品种改良。
Among those discussed are problems of crossing selected lines to obtain extra responses, and discrepancy of some theoretic results on selection limits.
本文还讨论了不同选择系杂交以获致进一步进展的问题，讨论了长期选择理论研究结果与实际模拟的偏差。
To improve traffic safety level and increase the efficiency of crossing facilities, the paper presents a methodology in studying selection preference of pedestrian crossing behavior.
为提高行人的交通安全水平和过街设施的使用效率，研究行人对过街设施的选择行为。
应用推荐