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前言在提高玉米单位面积产量的措施中,我国及外国的生产实践都证明,大力提倡杂交种,尤其是自交系间的杂交种——双杂交种,乃是重要的增产关键。现阶段我国玉米杂交种,正在从品种间杂交种迅速地过渡到改用双杂交种的过程中。配制综合品种,是利用优良的单杂交或双杂交种种子,或利用优良自交系的种子,来保持杂交优势到一定年限。它并不妨碍进一步推广双杂交种,
Preface In the measures to increase the yield per unit area of corn, production practices both in China and in foreign countries prove that it is an important key to increase production vigorously to promote hybrids, especially the hybrid between two inbreds, two-hybrids. At this stage, China’s maize hybrids are rapidly transitioning from the cross-species hybrids to the switch to two-hybrids. The preparation of comprehensive varieties, is the use of good single hybrid or two-hybrid seeds, or the use of fine seeds of inbreds to maintain the hybrid advantage to a certain age. It does not prevent further promotion of two-hybrids,