Development of branchless watermelon near isogenic lines by marker assisted selection

Pruning is time-consuming and laborious in watermelon cultivation,which can not meet the needs for simplified cultivation in the future.The development of branchless lines will provide important germplasms for breeding watermelon varieties and is an important method for genetic improvement.In this study,the watermelon accession,Wu Cha Zao(WCZ)is a branchless inbred line that carries the branchless gene Clbl,which was used as the donor parent to develop branchless near isogenic lines(NILs).To construct the NILs of Clbl,WCZ crossed with the normal branching watermelon inbred line WT20 which was used as the recurrent parent.The co-segregating markers dCAPS10 and Indel1 with Clbl were used for foreground selection,and a total of 108 SSR markers was selected with good polymorphism between two parental lines for background selection which had relatively uniform distribution across 11 chromosomes.Using these markers to select individuals from the BC_(1)F_(1),BC_(2)F_(1),and BC_(2)F_(2) generations,three NILs with a proportion of recurrent parent genome(PRPG)>99%were finally obtained.The lateral branch and plant height phenotypes did not significantly differ between the NILs and WCZ,indicating that the NILs of Clbl under the genetic background of WT20 has been successfully developed.These results provide ideal materials for further in-depth analysis of the genetic mechanisms of lateral branch development and ideal plant architecture breeding in watermelon.

少侧蔓突变西瓜的株形与遗传基因bl的研究

一、目的与材料方法 西瓜〔Citrullus lanatus(Thunb)Matsum et Nakai)的少侧蔓突变是1969年前后,由新疆石河子142团技术员徐利元在‘苏联2号’西瓜的生产田中偶然发现的。由于该突变主蔓分枝少,减轻了大面积西瓜田间管理中的打杈作业强度,因此受到欢迎和重视。本试验利用黎盛显后来育成的‘无杈早’为材料,研究了西瓜少侧蔓突变的形态特征和遗传特性,从而为西瓜少侧蔓基因的确定和命名提出建议。

西瓜少侧蔓突变型的株形及遗传基因bl的研究

西瓜少侧蔓型又称无杈西瓜,植株紧凑,主蔓上分枝明显少于正常植株,其来源为新疆石河子垦区西瓜生产田中的自然突变。据遗传测定:少侧蔓性状是由一个隐性单基因控制的,建议将之命名为 bl(branch less)基因。