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- back cross mating 回交, 逆代杂交
- Gene effects and effective gene number on litter size in pig are estimated from the mean and the mean variances of 6 generations including Taihu Pig(P1),Landrace (P2),first cross(F1),second cross(F2),third cross(F3)and back cross(B2). 利用太湖猪（P1）、长白猪（P2）、杂交一代（F1）、杂交二代（F2）、杂交三代（F3）； 和回交一代（B2）等6个世代产仔数的材料，分析了猪产仔性状的基因效应和基因数。
- In order to analysis the genetic characteristic of male sterility, test cross, sister cross, back cross, reciprocal cross and self-pollination were conducted with these male sterule plants. 通过正交和反交对不育株的所属类型进行分析，结合自交、回交分析其遗传特点。
- Back Cross in Fallaway position leading to Wing 并退步位置的后退交叉进入翼步
- Rose bushes shoot again after being cut back. 玫瑰丛修剪後还能再长出新枝。
- A near isogenic line strain(NILs)was selected by repeated back crossing.Two NILs of dimehypo-resistance(Rd)and cartap-resistance(Rp)were selected by 12 generations back crossing. 通过12代回交，建立了抗杀虫双和抗杀螟丹近等基因系，并对其多功能氧化酶环氧化活性和生物学特性进行了比较研究。
- Back cross breeding techniques by Taigu genic male sterile wheat 利用太谷核不育小麦进行小麦回交育种技术简介
- He trudge three hour in the snow to get back home. 他在雪中跋涉三个钟点才回到家。
- The crowd fell back to let the players through. 人群后退让运动员们通过。
- Do exercise every day and you'll be back in condition. 每天锻炼锻炼，你很快会恢复健康的。
- The ship beat back against a monsoon. 船逆着季风艰难地行驶。
- I flap the flies away but soon they fly back. 我把苍蝇赶走，但一会儿又飞回来了。
- I never lend books; you never get them back. 我的书决不外借，因为总是有去无回。
- She leaned her head back and whispered the news. 她向后仰着头，小声说出了这个消息。
- The talks have been put back to Friday morning. 谈判推迟到星期五早上进行。
- He hated to tuck his tail and back down now. 他讨厌此时夹着尾巴退回来。
- After a long coma the sick man slowly came back. 昏睡了好久以后，那个病人慢慢地恢复了活力。
- Back in Nigeria we used to play a lot of tennis. 我们以前在尼日利亚经常打网球。
- The crowd fell back to let the ambulance through. 人群往后退，让救护车通过。
- The teacher get a raspberry as she turn her back. 该教师转过身去时有人用舌与唇发出嘲笑她的声音。
