【作者】 兰红玲；

【导师】 樊治成；

【作者基本信息】 山东农业大学 ， 蔬菜学， 2003， 硕士

【摘要】 本试验选取遗传差异显著的7个自交系以及配制的7个杂交组合为试材，研究了西葫芦杂种一代产量优势形成的农艺学、生理学和遗传学基础，以期为杂种优势利用、亲本选择选配和优势预测提供理论依据。主要研究结果如下：1.农艺学性状相关分析及杂种一代优势表现分析表明，单株结果数、单果重、果实发育速度、雌花数、座果率、果长、果粗、早期单株产量、早期单株结果数、早期单果重等性状与单株产量呈显著或极显著正相关，且杂种一代均表现为正向优势，以单株产量、果实发育速度两个性状优势尤为明显，平均超亲优势指数均为1.61。始花期、始收期与单株产量呈显著负相关，杂种一代表现为负向优势，平均超中优势指数分别为0.96和0.97。杂种一代与单株产量密切相关的农艺学性状较其亲本均有不同程度的优势表现，构成产量优势形成的农艺学基础。2.苗期、结果中期、结果末期光合速率与单株产量呈显著或极显著正相关，且杂种一代均表现为正向优势，以苗期和结果末期优势尤为明显。不同生长发育期叶面积与单株产量相关性均达显著或极显著水平，且杂种一代叶面积较其亲本均表现出明显的正向优势。结果中期叶绿素b含量、结果末期叶绿素a/b与单株产量的相关性达显著水平，而且杂种一代较其亲本表现为正向优势。杂种一代较其亲本拥有更大的光合面积，对光照尤其是弱光利用率高，整个生长发育期植株均能维持较高的光合速率，可能是杂种优势形成的重要生理基础之一。整个生长发育期，杂种一代植株中干物质含量较其亲本均表现出不同程度的正向优势，以结果期优势更为明显,优势指数均在1.40以上。生长前期杂种一代干物质在营养器官中积累分配和结果中期、结果末期在果实中积累分配较亲本均表现出明显优势，可能是产量优势形成的又一重要原因。从氮、磷、钾养分积累分配分析可以看出，苗期杂种一代与其亲本无明显差异，结果期，杂种一代均表现出较其亲本更快的营养元素积累能力，<WP=7>生长前期营养器官和后期果实中养分积累分配强优势表现表明，杂种一代较其亲本能够更为合理的分配氮、磷、钾营养成分，养分利用率高，有助于产量优势形成。3.遗传距离与单株产量的优势指数呈不显著程度的负相关，表明遗传距离并非越大越好。亲子相关分析表明，杂种一代农艺学性状均不同程度的受到亲本影响，可以通过亲本性状表现对杂种一代与亲本密切相关的性状进行初步预测，育种时应注意以适当的品种作亲本。更多还原

【Abstract】 In this experiment, seven inbreds which had different genetic backgroud together with seven hybrids breded with them were studied to find the agronomical, physiological and genetic mechanism of heterosis performance. The aim was to provide theoretical basis for heterosis utility, parent selection and heterosis prodiction. The result were as follows:1. Correlation analysis between agronomical characters and heterosis performance in the hybrids indicated that the fruit number per plant, fruit weight, fruit growth rate, female flower number, percentage of fruit setting, early yield per plant, early fruit number per plant, early fruit weight length of fruit and diameter of fruit all had positive correlation with the yield per plant at significant or very significant level. The hybrids showed positive mid-parent heterosis and even super-parent heterosis in these characters. Among them, the heterosis of the yield per plant and the fruit growth rate were much higher, whose mid-parent heterosis index reached 1.61, and super-parent heterosis index reached 1.53 and 1.47 respectively. However, the period from planting to flowering and from planting to first harvesting. had negative relationship with the yield per plant and the hybrids showed negative heterosis. Their mid-parent heterosis index were 0.96 and 0.97 respectively. In a word, all of the characters which were closely correlated with the yield per plant had heterosis performance compared with their parents, this may be the agronomical basis of heterosis forming.2.In the stage of seedling, middle fruiting and end fruiting, the correlation coefficient between the photosynthetic rate and the yield per plant reached significant even very significant level. The hybrids all performed positive heterosis and the heterosis were especially prominent in the stage of seedling and end fruiting. In different stages, the leaf area all correlated with the yield character at significant or even very significant level. The hybrids showed positive heterosis in the whole life. The character of chlorophyll b in the middle fruiting stage and the chlorophyll a/b in the end fruiting stage were significantly and positively correlated with the yield character and the hybrids had<WP=9>heterosis performance. In conclusion, the hybrids had larger leaf area, they could utilize light especially weak light more usefully, and in the growth stage long the plant could always maintain higher photosynthesis rate, which may become one of the important physiological basis of heterosis performing.As for the dry matter content in the plant, he hybrids all showed heterosis performance compared with their parents at different level in the whole growth stage. The heterosis performance were especially obvious in the three fruiting stage, whose heterosis index were all above 1.40. In the former growth stage, the dry matter in the vegetation organ of the hybrids showed strong heterosis compared with their parent, so did that in the fruit organ during the middle and end fruiting stage, which may be another important course of yield hetersosis forming.From the analysis of the nitrogen, phosphorus and potassium nutrition accumulation and division, we could see that during the former growth stage, there were not much difference between hybrids and their parents, while in the fruit stage, the hybrids absorbed the nutrition faster and more stably than their parents. In the early growth stage, the nutrition accumulated in the vegetation organ and in the latter stage that in the fruit of hybrids all showed great heterosis. So, the hybrids could utilize the nutrition more rationally and efficently. These may help to form yield heterosis.3. The negative but not significant correlation between the genetic distance and parents showed that it wasn’t the case that the greater the genetic distance were, the better. The relationship between hybrids and their parents indicated that the performance of agronomical characters in the hybrids were all affected by their parents at different level, so the heterosis更多还原