【作者】 于澄宇；

【导师】 郭蔼光； 胡胜武；

【作者基本信息】 西北农林科技大学 ， 生物化学与分子生物学， 2003， 硕士

【摘要】 油菜产量和其它农艺性状的杂种优势很明显。本研究用形态学方法、同工酶法、RAPD三种不同水平遗传标记方法分析获得遗传距离，研究甘蓝型油菜杂种优势与亲本遗传距离的关系，探索是否可以构建一套用于筛选亲本的遗传标记体系。 供试材料为适应黄淮流域气候条件的优良甘蓝型油菜亲本，6个甘蓝型油菜（Brassica napus L.）同质异核雄性不育系（以Shaan 2A为母本，用相应的保持系为父本杂交并连续回交得到）及相应6个保持系，5个恢复系。按NCⅡ的p×q设计配制6个不育系×5个恢复系的30个杂交组合。2001-2003年在陕西杨凌进行杂交种及亲本3重复随机区组设计比较试验。主要结果有： 1．子叶期油菜显示：酸性磷酸酶同工酶（ACP）近阴极区有9条带，保守条带1条，其余8条在11个亲本间有多态性；过氧化氢酶同工酶（CAT）共显示至少6条带，其中2条保守，4条具有多态性；过氧化物酶同工酶（POD）共显示6条带，2条保守，4条具有多态性；酯酶同工酶（EST）共显示17条带，保守条带3条，14条有多态性。油菜幼芽的α-AMY表现3条带，其中1条保守；谷草转氨酶同工酶（GOT）出现3条带，2条具多态性。油菜亲本种子可溶性蛋白SDS-PAGE电泳可见条带18条以上，但不易分辨，只有7条为多态性条带。总的多态性比率66.13％。用以上所得同工酶和蛋白质数掘进行遗传相似度分析。父本与母本之间遗传距离GD_Lso，范围为0.143～0.535，平均GD为0.297。可见供试材料基于同工酶和蛋白质标记的遗传相似度较高。 2．用100条随机引物对亲本DNA扩增，其中34个引物对11个亲本共扩增出251条带，具有明显多态性条带136条，占52.18％，平均每条引物扩赠4条多态性带。基于RAPD扩增结果计算遗传距离GD_Rapd，6个父本与5个母本间的平均遗传距离是0.434，遗传距离范围是0.309～0.553。基于RAPD遗传相似度比基于同工酶和蛋白质标记的低。 3．将亲本的20个形态学特征分为55个指标，分析亲本多态性。父本与母本间遗传距离GD_Mor，范围为0.333～0.812，平均为0.641，相似系数范围0.187～0.667。两组亲本的形态学相似性较小。 4．三种GD之间相关性不显著，三者信息重叠较少。以遗传距离GD=O.390为阀值，可将参试材料聚为3组。第1组包括6个保持系（B1、B2、B3、B4、B5和B6）和3个生化和分子标记与甘蓝型油菜杂种优势的关系恢复系（Cl、C3和CS）;第2组和第3组分别仅有l个恢复系C2和C4。该结果不能清楚表明参试的自交系间遗传距离与地理起源关系。 5.同一亲本的所有组合双亲间遗传距离的平均值，与一般配合力GCA的相关系数均未达显著水平。而特殊配合力与产量、产量杂种优势的相关系数分别是0.670和0.560，达到极显著水平。特殊配合力与遗传距离的相关性只在2003年存在，SC际。与G氏，、‘和阳性标记距离G氏:.1，显著负相关，与GD而pd.极显著正相关，而与GD.、.，负相关不显著。 6.GD、、‘与杂种分枝数、千粒重及初花期分别极显著负相关、极显著负相关和正相关。G氏lI，。与株高、分枝数、角果数和角粒数分别显著相关、显著负相关、极显著负相关和显著相关。G氏.r与各性状不相关。总遗传距离GD卜，t:与株高、角果数和角粒数分别极显著相关、极显著负相关和显著相关，而与产量相关不显著。 7.GD.、.与杂种千粒重和初花期中亲优势分别显著负相关（一0.475）和显著正相关（0.524）。G氏、、.与全株角果数MPH显著负相关（一0.365）。遗传距离与产量杂种优势相关关系未达到显著水平（一0.334）。表明不能直接根据基于所有标记的遗传距离的大小来预测杂种产量优势。 8.从55个形态学标一记中筛选出25个对产量因子有显著影响的阳性标记，阳性率45.5%;从41个同工酶标一记中筛选出22个阳性标记，阳性率53.7%;从136个RAPD标记中筛选出72个阳性标记，阳性率52.9%。基于阳性标记的遗传距离GDt二‘，与农艺性状相关性明显增加，但与各农艺性状中亲优势相关性仍不显著，与产量M四相关系数为一0.25，未达到显著水平。再次表明不能根据亲本遗传距离的大小预测杂种产量及特殊配合力。 9.从108个阳性标记中共筛选出29个RAPO标记，7个同工酶标记和7个形态标记，其杂合互补对产量因子有增效作用，所占比例为39.8ty0。在此基础上计算遗传距离GD.，lL、，其与农艺性状的相关性进一步增强。GD.，.L、与产量相关极显著，决定系数为0.336。虽然GO二L，、GD..:.，，和GDf’lL、与产量相关性一步步增大，但决定系数小，并不能预测杂种产量。7个农艺性状中，GD.，.刀、只与株高的中亲优势达到显著水平，其它相关不显著。 通过基于三种不同水平遗传标记的一般杂合度、特殊杂合度和增效标记杂合度这三层统计量与油菜农艺性状及其杂种优势的相关分析，综合性说明了遗传杂合度与甘蓝型杂种的一些农艺性状显著相关，而与其杂种优势相关不显著。植物杂种优势机理非常复杂，受遗传因素控制外，还受环境条件的影响，用分子遗传距离预测杂种优势离实际应用还有一段距离。更多还原

【Abstract】 In rapeseed(Brassica.napus L)strong heterosis has been reported for seed and agronomic traits. The level of genetic diversity between parents as estimated using isozymic and molecular markers is considered a tool for predicting the hybrid performance and heterosis of crosses. To explore this possibility, GD(genetic distance) on three different level, including morphological, isozymic and RAPD markers, were used to predict the performance of hybrids. Eleven elite rapeseed lines, including 6 maintainer lines to Shaan2A Cytoplasmic Male Sterility and 5 restorer lines espectively, were selected on the basis of different geographic origin, and the corresponding male sterile lines were crossed with restorer lines in a 6x5 NC II model to produce 30 Fl hybrids which were evaluated for seven agronomically important traits in a replicated field trials in Yangling. General combining ability (GCA) and specific combining ability (SCA) for seed yield and mid-parent heterosis (MPH) estimates were calculated on the basis of hybrid performance during the two year. Genetic distances (GD) for pairs of the 11 genotypes were calculated with diversity information based on morphological, isozymic and RAPD, and correlated with MPH estimates.The objectives of this paper were to (i) estimate heterosis for agronomic traits in rapeseed (Brassica napus L.) adapted to the region near Huanghe river and Huaihe river of China, and (ii) predict heterosis by means of morphological character, isozyme and RAPD as genetic distance measures.The results were described as follow:1. In cotyledonal stage of rapeseed, isozymes of ACP, CAT, POD, and EST showed nine, six, six, seventeen bands in PAGE respectively. In sprouted rapeseed both GOT and a -AMY showed three bands. Eighteen soluble protein bands of seed were detected in SDS-PAGE. The biochemical polymorphic ratio was 66.13%2. The eleven parents were assayed for random amplified polymorphic DNA (RAPD) with thirty-four primers, which generated 136 polymorphic bands and the polymorphic.ratio was 52.18%.3. The parental lines were assayed for polymorphisms using three classes of markers. GD(genetic distance) estimates were computed using Nei’s similarity coefficient based on these data considering each molecular marker set separately (GDIso, GDRapd, GDMor). Range of GDMor was 0.333-0.812, average GDMor was 0.641. Range of GDIso was 0.143-0.535, the average value of GD was 0.297. GDRapd between parents ranged from 0.309-0.553, the average value of GDRapd was 0.434. Genetic similarity among the eleven parents based on isozymes and soluble proteins was higher. The three measurements were not significantly correlated.4. Diversity in morphology, isozyme loci and RAPD were evaluated using UPGMA cluster. The eleven parents can be clustered into three groups by a threshold value equal to 0.390: group I including six maintainer lines and 3 restorer lines; group II and group III including one restorer line C2 and C4 respectively. The result cannot showthe relationship of the materials origination.5. Significant heterotic effects were detected for seed yield and other traits.. Highly significant GCA and SCA effects were observed for yield. Correlation between parents’ average GD and GCA was not significant.Meanwhile, the correlation between SCA and yield, and yield MPH were significant coefficent was 0.670 and 0.560). In 2002 and average of two year data , SCA did not correlate with GD though it did in 2003.6. It was significant negative, negative and positive that the correlation were tested between GDIso and number of branch, 1000-seed-weight and flowering respectively(P=0.01, P=0.01,P=0.05). Significant positive, positive, negative and negative correlation were checked out between GDaapd and plant height, number of branch, number of silique, mumber seed per silique respectively(P=0.05, P=0.05, P=0.01, P=0.05). Significant positive, positive, and negative correlation were checked out between GDTotal and plant height, mumber of s更多还原