| 摘要: |
| 【目的】研究西瓜属6个主要变种的染色体核型特征，为西瓜属作物品种亲缘关系鉴定及新品种培育等提供细胞学参考。【方法】以西瓜属6个主要变种饲用西瓜（PI296341）、普通西瓜（黑崩筋）、黑籽瓜（内蒙黑中片）、红籽瓜（江西信丰）、黏籽西瓜（PI254723）、药西瓜（PI386015）的根尖为试验材料，采用常规制片法制片，对其染色体数目、核型和进化趋势进行分析，并对6个变种的亲缘关系进行聚类分析。【结果】西瓜属6个主要变种的染色体类型均为二倍体（2n=2x=22），含有不同数量的m和M染色体；根据相对长度系数可知各变种包括L、M2、M1和s等4种类型，其中L型染色体在饲用西瓜（PI296341）、普通西瓜（黑蹦筋）、黑籽瓜（内蒙黑中片）、红籽瓜（江西信丰）、药西瓜（PI386015）中均有出现，只有黏籽西瓜（PI254723）中未见；s型染色体在红籽瓜和黏籽西瓜中未出现，在其他4个变种中均有出现。西瓜属6个主要变种染色体的平均臂比值为1.09～1.36，核型类型属1A型和1B型，核型不对称系数为52.20%～57.42%。西瓜属6个主要变种的染色体核型进化程度由高到低依次为黑籽瓜（内蒙黑中片）、黏籽西瓜（PI254723）、饲用西瓜（PI296341）、药西瓜（PI386015）、普通西瓜（黑蹦筋）和红籽瓜（江西信丰）。【结论】西瓜属6个主要变种的核型特征具有一定程度的差异，核型进化趋势总体由对称向不对称发展；在核型特征上，饲用西瓜与药西瓜、药西瓜与普通西瓜亲缘关系较近，而红籽瓜（江西信丰）与其他5个变种亲缘关系较远。 |
| 关键词: 西瓜变种 染色体 核型特征 |
| DOI： |
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| 基金项目:内蒙古自然科学基金项目（2016MS03560)；内蒙古科技计划项目(20090707,2010704,20110711,20120212) |
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| Karyotype analysis of 6 main varieties in Citrullus |
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WANG Ping,YANG Qin,WANG Jiming,et al
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| Abstract: |
| 【Objective】The karyotype characteristics varieties of 6 main varieties in Citrullus Schrad are studied in this paper,it provides cytological reference for identification of genetic relationship and breeding of new varieties of watermelon crops in the future.【Method】The karyotypes of six main varieties including var.Citroides (PI296341),var.Vulgaris (Heibengjin),Black seed watermelon (Neimengheizhongpian),Red seed watermelon (Jiangxixinfeng),ssp.Mucosospermus (PI254723) and C. colocynthis (PI386015) were studied using traditional squash method.Their chromosome number,karyotype characteristics and karyotype evolutionary trend were analyzed and cluster analysis was conducted to identify their genetic relationships.【Result】The ploidy levels of six main varieties were all diploid (2n=2x=22) with different numbers of “m” and “M” chromosomes.According to relative length index of chromosome,all six main varieties contained 4 types of L,M2,M1,and s.The “L” type chromosomes were found in Red seed watermelon (Jiangxixinfeng),Black seed watermelon (Neimengheizhongpian),var.vulgaris (Heibengjin),C. colocynthis (PI386015),and var.Citroides (PI296341) except ssp.Mucosospermus (PI254723).The “s” type chromosomes were found in varieties except Red seed watermelon (Jiangxixinfeng) and ssp.Mucosospermus (PI254723).The average arm ratios ranged from 1.09 to 1.36.Karyotype types were ‘1A’ and ‘1B’.Asymmetrical karyotype coefficients ranged from 52.20% to 57.42%.The karyotype evolution degrees were in the order of Black seed watermelon(Neimengheizhongpian)>ssp.Mucosospermus(PI254723)>var.Citroides(PI296341)>C. colocynthis(PI386015)>var.Vulgaris(Heibengjin)>Red seed watermelon(Jiangxixinfeng).【Conclusion】The karyotype characteristics of six main varieties had certain differences.The karyotype evolutionary trends of Citrulluswere changed from symmetric to asymmetric in general.Based on karyotype characteristics,the similarity between var.Citroides(PI296341) and C.colocynthis (PI386015) was high,while var.Megalospermus(Jiangxixinfeng) had low relationship with others varieties. |
| Key words: Citrullus Schrad. varieties chromosome karyotype characteristics |
