【作者】 陈凤真；

【导师】 何启伟；

【作者基本信息】 山东农业大学 ， 蔬菜学， 2008， 博士

【摘要】 本文选用西葫芦三个性状差异显著的自交系配制2个杂交组合,对其产量、熟性、果实性状和株型等主要农艺性状进行杂种优势、相关性及6个不同世代的遗传分析;利用RAPD技术构建了西葫芦的遗传图谱,并对国内外47份西葫芦种质进行了遗传多样性及亲缘关系分析。1.杂种一代的杂种优势结果表明:西葫芦杂种一代在产量构成性状方面均有不同程度的杂种优势表现,两个熟性性状有负向超亲优势,杂种一代的株型得到了改善。在产量构成性状方面:西葫芦的杂种一代的单株产量、单株结果数均表现超中优势;2个组合的F1单果质量均表现超高亲优势,超高亲优势分别为7.71%和15.75%;在坐果率方面,2个组合F1的均表现超亲优势,组合1的F1超中优势为14.98%,组合2的F1超中优势为17.70%。在产量构成性状方面表现出显著的杂种优势,说明F1具有高产的优势。在熟性性状方面:西葫芦的F1始花期和第一雌花节位均表现出负向超低亲优势,说明F1始花期提前,第一雌花节位降低,使得杂种一代具有早熟的优势。在果实构成性状方面:西葫芦的果实横径与果形指数均表现出杂种优势,西葫芦的果实整齐度均表现超高亲优势;以上说明杂种一代的果实性状得到改善,外观品质得到了提高。在株型构成性状方面:西葫芦的叶片数均减少,且低于低值亲本;在节间距方面,2个组合的F1节间距均表现负向超中优势,优势分别为-32.26%和-37.21%;以上结果说明西葫芦杂种一代的株型得到改善,株型表现得更紧凑。2.相关性结果表明:主要产量性状之间及产量性状与熟性性状、果实性状和株型性状密切相关;熟性性状与果实性状及株型性状密切相关。如单株产量与单果质量、单株结果数、座果率性状呈正相关,单株产量与第一雌花节位、始花期、果实横径及果柄宽度的相关系数密切负相关;座果率与瓜柄长、果实长度及果形指数性状显著相关;第一雌花节位与始花期、瓜柄长度、果实长度、株高、叶片数及节间距的相关性达到显著水平。西葫芦果实性状之间及果实性状与株型性状密切相关;如:果形指数与果柄宽度相关性达到负的极显著水平,与果实长度、果实整齐度、株高、叶片数、节间距等达到正的显著或极显著水平;果实整齐度与株高、叶片数及节间距等性状密切负相关。株型性状之间关系密切,株高与节间距密切相关;叶片数于节间距密切负相关。西葫芦产量主要构成性状、熟性性状、果实性状及株型性状之间关系密切,互相影响。3.西葫芦主要农艺性状进行遗传分析。表明:果实颜色为质量性状,绿色对白色为显性;西葫芦单株产量符合D-2模型,即一对加性主基因+加性-显性多基因的遗传,遗传传效应以加性效应为主,主基因起决定作用;西葫芦的单果质量性状符合B-1模型,即加性-显性-上位性两对主基因模型,起主要作用的是显性效应与显性×显性互作效应,其次是加性效应;单株结果数符合D-2模型,由主基因与多基因共同控制,且组合1以加性效应为主,组合2除了加性效应之外,显性效应也起了重要的作用;西葫芦的座果率以加性效应为主;西葫芦的始花期性状符合加性B-1模型,组合1与组合2的显性效应估计值之和均为负值,使得杂种一代始花期性状呈现出负向超亲优势;西葫芦的始花期性状以加性效应和加性×显性上位性互作效应为主。在第一雌花节位方面的研究结果表明:组合1的第一雌花节位加性效应起主要作用,组合2的第一雌花节位加性效应与显性效应同时起作用; 2个组合的显性效应值均为负值,使得杂种一代第一雌花节位性状呈现负向超亲优势。西葫芦果实性状符合B-1模型或D-2模型,B-1模型由主基因控制,D-2模型由一对主基因和多基因共同控制,但多基因的遗传率较高。西葫芦的株高、叶片数和节间距遗传均为加性-显性-上位性两对主基因(B-1)遗传模型,西葫芦的株高性状均以加性效应为主,其次均为加性×加性上位性互作效应和显性效应;西葫芦的叶片数性状以加性和显性效应为主;组合1的节间距遗传效应以加性为主,兼有加×加上位性效应值,控制组合2节间距的主要是加性效应,兼有显性效应和显×显上位性。西葫芦的节间距基因显性效应值之和均为负值,使得杂种一代节间距缩短,表现负向超亲优势。可见,在西葫芦多数性状中,显性效应为正值,是该性状超亲杂种优势形成的遗传基础;在某些性状遗传中,显性效应值为负值,使F1表现负向超亲优势如第一雌花节位、始花期、叶片数及节间距等,上位性普遍存在西葫芦的农艺性状中。4.利用西葫芦蔓生/白皮自交系q-1和矮生/绿皮自交系23-4G杂交获得的93份F2:3个体,采用RAPD分子标记进行分析,建立了西葫芦的优化反应体系,并构建了包含20个连锁群,由589个标记组成的连锁图谱,覆盖基因组2060.9cM,平均图距3.50cM。5.利用RAPD技术对国内外47份西葫芦种质进行了遗传多样性及亲缘关系分析。从520条随机引物中筛选出30条能产生稳定多态性的引物用于RAPD反应,共扩增出367条带,其中302条表现多态性,占总数的82.29%,遗传多样性高,种质资源丰富。聚类分析将47份西葫芦种质分为2大类。在第Ⅰ类群中,可将32份种质分为4个亚类。第Ⅱ类群分成5个亚类。47份材料的相似系数分布在0.63~0.89之间,西葫芦遗传距离较窄。从生长习性来看,矮生与半蔓生的亲缘关系最近;从皮色来看,白色与绿色亲缘关系最近,其次为黄色与绿色,亲缘关系最远的为白色与花皮。更多还原

【Abstract】 By using six generation of two summer squash crosses, we studied the heterosis performance, the correlation between characters and the genetic mechanism of heterosis of summer squash. By using RAPD, the genetic map of summer squash was constructed. And RAPD analysis was applied to assess the genetic diversity and relationship in 47 summer squash germplasm.1. The result of heterosis analysis indicated that: there were different heterosis in yield characters; There were negative heterosis in two maturation characters and plant characters were improved. In yield composed characters, character of yield per plant and fruit number per plant showed the middle heterosis;Individual fruit mass of summer squash of hybrid F1 was both higher than their high parent; Ratio of fruit setting of summer squash of hybrid F1 showed the middle heterosis, and the heterosis of cross 1and cross 2 was separately 14.98%and 17.70%.The distinct heterosis in yield characters showed that hybrid F1 was higher yield than parents. In maturation characters, early flowering season of summer squash of hybrid F1 was more early than their early parent and node number of 1st female flower of summer squash of hybrid F1 was lower than their low parent; So hybrid F1 showed more early than parents. In the fruit composing characters, fruit length of cross 2 and fruit width of two crosses of hybrid F1 all showed different heterosis; Fruit uniformity of summer squash of hybrid F1 both were higher than that of high parent ;So the fruit shape characters of hybrid F1was better improved. In the plant composing characters, leaf number of summer squash of hybrid F1 decreased and was fewer than parents; Length of summer squash of hybrid F1 showed the middle heterosis, and the heterosis of cross 1and cross 2 was -32.26%and 37.21%; So plant characters of hybrid F1 were improved differently and were more compact.2. Correlation analysis indicated that: yield and yield composing characters had intimate relation with maturation characters, fruit characters and plant characters; maturation characters had intimate relation with fruit characters and plant characters. Yield per plant had positive significant relation with fruit number, individual fruit mass, and fruit setting ratio; While yield per plant had negative significant relation with early flowering season, node number of 1st female flower, fruit width and fruit stalk width; Ratio of fruit setting had significant relation with fruit stalk length, fruit length and fruit shape index; Node number of 1st female flowering had significant level with early flowering season, fruit stalk length, fruit length, plant length, leaf number and internode length; Fruit shape index had negative significant relation with fruit stalk width, but it had positive significant relation with fruit length, fruit uniformity, plant length, leaf number and internode length; So fruit characters had significant relation with each other and plant characters. Plant characters had significant relation with each other; Leaf number had negative significant relation with internode length.Yield composed characters, maturation characters, fruit characters and plant characters had significant relation and interacted with each other.3. Genetic analysis indicated that: fruit color was a qualitative character; green was dominant to white; Yield per plant of summer squash was D-2model, and additive effect played main role, but major gene played decisive role; Individual fruit mass accorded with B-1model, dominant effect and dominant×dominant epastasis mainly played role, and secondly additive effect played role; Fruit number per plant of summer squash fitted D-2 and was together controlled by major gene and polygene, and additive effect mainly played role on cross 1, while additive effect and dominant effect both played role on cross2; Genetic effect of fruit setting ratio of summer squash was mainly additive effect; Early flowering season of summer squash accorded with B-1model;dominant effect estimated value of summer squash was negative, so hybrid F1showed negative heterosis, and genetic effect of early flowering season of summer squash was mainly additive effect and additive×dominant epastasis; The result in node number of 1st female flowering showed that additive effect play main role on cross1 and additive effect and dominant effect together play main role on cross 2; Dominant effect estimated value of was negative, so hybrid F1showed negative heterosis; Fruit characters of summer squash accorded with B-1model or D-2 model, and fruit characters according with B-1model was controlled by major gene , but fruit characters that according with D-2 model was controlled by major gene and polygene, but polygene effect occupied higher percentage than major gene; Leaf number and internode length of summer squash both accorded with B-1model; Genetic effect of leaf number of summer squash was additive and dominant effect; Genetic effect of internode length of cross 1 was mainly additive effect and concurrently additive×additive epastasis,while genetic effect of internode length on cross 2 was mainly additive effect and concurrently dominant and dominant×dominant epastasis;Dominant effect estimated value of summer squash was negative, this made internode length shorten, so hybrid F1showed negative heterosis; Additive effect mainly played role on plant length of summer squash, and secondly additive×additive epastasis and dominant effect played role.So in the heredity of most character, dominant effect was positive, and dominant effect was the genetic basis of heterosis; In some other characters, dominant effect was negative and lower than of additive effect, this made hybrid F1 show negative heterosis like node number of 1st female flowering, early flowering season and internode length etc; epastasis widely existed in the heredity of summer squash characters.4.A 589 point map of summer squash was constructed from 93 F2:3 individuals each cross between summer squash q-1(vine/white) and23-4G(bush/green). The map delineated 20 linkage groups spanned 2060.9cM with an average distance of 3.50cM between the markers.5.RAPD analysis was to applied to assess the genetic diversity and relationship in 47 summer squash germplasm. Genomic DNA of 47 summer squash germplasms was amplified by RAPD. 30 polymorphic primers, screened out of 520 random Primers, were used and produced 367 reproducible bands. Of them, 302 bands (82.29%)were polymorphic. The cluster analysis divided the germplasm used in this study into 2 groups, which was not completely in agreement with the traditional taxonomy on summer squash. The first group was divided into four sub-groups. The second group was divided into five sub-groups. The similarity coefficient of 47 germplasms was between 0.63~0.89, so the genetic distance of summer squash was narrow; For growth habit, genetic relationship between cluster and half-sprawl was nearest.更多还原