【作者】 曾斌；

【导师】 唐灿明；

【作者基本信息】 南京农业大学 ， 作物遗传育种， 2008， 硕士

【摘要】 棉花产量杂种优势的机理研究对棉花杂交种选育及应用具有至关重要的作用。但由于作物的杂种优势遗传机理研究因其复杂性至今仍未能取得突破进展,因此,从产量表型及相关生理过程分析出发研究杂交棉产量优势形成的生理机理将是最终揭示杂种优势遗传机理的有效途径。本文以选取南抗3号、鲁棉研15号和湘杂棉3号等三个强优势转基因抗虫杂交棉为材料,对杂交棉及亲本在三个环境下的籽棉产量优势表现以及产量优势组成因子对产量优势的贡献做了较为系统的研究,分别从解剖学、光合生理及高温逆境生理等角度阐述了杂交棉生理优势表现及其与产量优势形成的关系,旨在揭示杂交棉产量优势形成的生理机理,为杂交棉产量杂种优势机理研究提供资料,为杂交种选育提供依据。1.生态条件对籽棉产量的影响较大,但杂交种与亲本之间的籽棉产量杂种优势表现关系受环境影响较小。籽棉产量与单株结铃数(0.745^**)和单铃重（0.706^*）有极显著或显著正相关性。杂交种的籽棉产量超亲优势由杂种的单株结铃数和单铃重两个组成因子共同的超亲优势或同时结合了两个亲本的结铃数和单铃重优势组成。五室铃率表现明显的基因型差异,但也受环境影响很大。五室铃率与单铃重之间存在显著的正相关性（0.610^*）,五室铃的平均单铃重比四室铃显著大17.43%。杂交种及亲本在“三桃”构成上有显著差异,三个杂交组合的杂交种的结铃数优势一致表现为伏前桃>伏桃>秋桃。杂交种的结铃性优势主要来源于伏前桃和伏桃的结铃优势。杂交种的伏前桃结铃数优势可能与结铃率优势有关。2.三个杂交组合共9个供试材料盛花期的主茎功能叶（倒4叶）主叶脉维管束表现有无分支型、二分支型和三分支型等三种类型,三分支型最发达,有利于营养物质的运输。三个组合均表现为:一个亲本的主茎功能叶维管束属于二分支型或无分支型,另一个亲本的主茎功能叶维管束为三分支型,其杂交种均为三分支型,表现出显性遗传的特征。三分支型维管束结构可能是棉花高产品种和杂交种产量优势形成的基础之一。三个杂交种的栅栏组织与海绵组织比例优势表现比较一致,均在1.12-1.15之间,下表皮单位叶面积气孔总面积均表现超亲优势,这可能是光合作用优势形成的基础之一。果枝叶柄与铃柄的导管数目和单个导管面积间显著正相关,说明果枝叶比功能叶与铃的发育更密切。3.湘杂棉3号正、反交杂交种和父本的光合速率日变化均为单峰型,母本为双峰型。杂交种光合速率超亲优势表现有明显的日变化。正、反交杂种的光合速率的最大超亲优势分别为27.34%和43.13%,均出现在午后13:00-17:00之间。光合速率超亲优势与光强的相关系数为0.861,达极显著水平,其次是湿度(-0.71^**)和大气温度(0.667^**)。杂交棉光合速率超亲优势主要不是最大光合速率的超亲优势,而是在高温、高光强等逆境条件下维持相对较强光合作用的能力。高温下的叶片自降温能力有明显优势,光合优势可能与叶片自降温能力关。杂交种在强光、低湿和高温逆境下的光合作用超亲优势可能是杂交棉产量优势形成的重要生理基础。4.南抗3号开花期主茎功能叶和第一果枝叶的色素总含量（SPAD值）的广义遗传力分别为10.71%、30.14%,单铃重、衣分、子指的广义遗传力分别为93.33%、91.63%和87.60%。单铃重的遗传变异系数最大、遗传力高,是可进行早期世代有选择潜力的育种指标。果枝叶的SPAD值与单株籽棉产量（0.163**）、单株皮棉产量（0.139**）、单铃重（0.148**）、结铃数（0.167**）等均有极显著正相关。果枝叶的SPAD值可作为棉花产量光合生理育种的参考指标。三个环境下南抗3号正交一代的光饱和光合速率均表现为中亲优势。杂种的光合特性受到母性遗传的影响,应注重母本光合特性的选择。杂交种的低光补偿点和高饱和点可能是杂种在多环境下光合特性优势表现的基础。叶绿素b和叶绿素a/b比值可能是影响光合作用的内在因子。5.南抗3号父本的花粉萌发临界温度在35℃-40℃之间,正反交杂种和母本的临界温度在40℃-45℃之间。南抗3号正、反交杂种及其亲本的花粉管在花柱中生长的临界温度在30℃-35℃之间。南抗3号正交一代的柱头上的花粉萌发数和花粉管在花柱中的生长速度均有明显的中亲优势。杂交后代的耐高温能力存在明显的母本细胞质遗传效应。40℃对所有材料的花柱生长总长度的促进作用最大,35℃次之,45℃最小。37/27℃高温处理可以影响南抗3号父本开花期16天的幼蕾的雄蕊发育,诱导败育,幼蕾的苞叶面积在在1.3×1.3cm-1.8×2.1cm之间。但37/27℃高温处理对正交杂种和母本的花粉发育无明显影响。更多还原

【Abstract】 The studies on the mechanism of heterosis will greatly influence to the selection and application of breeding in hybrid cotton. However, the genetic mechanism of heterosis in seed cotton yield has not yet been able to achieve breakthroughs in progress because of its complexity, therefore, will embark the studies on the physiological mechanism from the phenotype analysis of yield and corrective physiological process will be the effective way to finally reveal the heterosis heredity mechanism.Emphasized on studying the heterosis in output of seed cotton and the physiological basis of heterosis for yield by using three transgenic Bt pest-resistant cotton hybrids Nankang3, Lumianyan15 and Xiangzamian3 and their parents. The heterosis for yield and the actions which factors of yields played in the yield heterosis under three different environments have been investigated systematically, and the relationship between the heterosis in physiological process and the yield heterosis was introduced also respectively from anatomy, the photosynthesis physiology, and the physiology suffer from high temperature adverse circumstance. The objective of the present study was to evaluated the physiological basis and accumulate data for the heterosis heredity mechanism studies and to provide guidelines for hybrid selective breeding. Results are summarized as follows:1. The yield was significantly influenced by the ecological condition.However, the tendency of F₁ heterosis performance had small environmental effect. The seed cotton output was signicantantly positively related to number of bolls per plant（0.745**） at 1% level of probability and boll weight（0.706*） at 5% level probability. The source of heterosis of yield in three hybrids rooted in over better-parent heterosis for the number of boll per plant and also in boll weight or based on the combination of mid-parent heterosis in number of boll per plant and boll weight. There was obvious difference in rate of five-cabins boll between different genotypes, but also was influenced by the environmental effect. The rate of five-cabins boll had signifcantant positively related to boll weight（0.610*） at 5% level of probability. The average boll weight of the five-canbins boll was higher than four -cabins boll for 17.43%. The hybrids and the parents had the remarkable difference in the constitution of the befor hot-boll、hot-boll and autum-boll. The heterosis in number of boll per plant exhibited before hot-boll > hot-boll > autum-boll with consistent in three hybrids. The heterosis in number of boll per plant of befor hot-boll and hot-boll constituted the main source of heterosis in number of boll per plant, specially for proportion of before hot-boll, but the little heterosis in autum-boll number of boll per plant. The heterosis of number of boll per plant maybe associate with the heterosis in boll retention of before hot-boll.2. There were significant differences between hybrid and its parents of Nankang3、Lumianyan15 and Xiangzamian3 in distribution of vascular bundles in the leaf nervures of the functional leaf（the fourth from top）in main stem during flowering stage. Three types of vascular bundles, three-offshoot, two-offshoot and no-offshoot were observed in leaf nervures of all tested materials. These were three-offshoot type in three hybrids and one of their parents, implying that the three-offshoot type was inherited dominantly., suggesting that there existed transgressive or mid-parent heterosis in all hybrids. The toal area of stomata per unit leaf area was a useful index for characteristic of stoma. The heterosis for the ratio of palisade tissue to spongy tissue which was 1.12～1.15 and the transgressive heterosis in toal area of stomata per unit leaf area on down leaf surface maybe the basis of heterosis for photosynthesis. There was significant positive correlation between leaf stalk of fruit branch and boll stalk in the number of vessel and area of a vessel, demonstrated that the leaves on fruit branch have more contribution to the boll development than functional leaves in stem（R²₁=0.4791*, R²₂=0.4702*）.3 Two photosynthesis diurnal patterns were observed among Xiangzamian3 hybrids and their parents during flowering stage, of which Xiangzamian3 hybrids and male belonged to one-peak pattern and female showed a bimodal diurnal pattern. Hybrids showed significant over better-parents heterosis on photosynthesis. The biggest heterosis for photosynthetic rate in reciprocal hybrids was respectively 27.34% and 43.13% which were observed during 13:00-17:00. The over better-parent heterosis in photosynthesis was positively related to light intensity（0.861**）, and secondly to humidity（-0.717**） and thirdly air temperature（0.667*） at 1% or 5% level of probability. The source of heterosis for photosynthesis was not from the heterosis for the max photosynthesis but for ability of keeping the max photosynthesis under high temperature and light conditions. It was probable that there was affinity between heterosis on photosynthesis and heterosis in ability of leaf temperature depressing. It was concluded that the over better-parent heterosis for photosynthesis under high temperatures and light.was physiological basis of yield. 4 The general heritability in the broad sense of the total pigment content （the SPAD value） was respectively 10.71% and 30.14%, of which the functional leaf（the fourth from top）in main stem and the first fruit branch leaveses during flowering stage. The general heritability in the broad sense of boll weight、lint percentage and seed index respectively was 93.33%、91.63% and 87.60%. The boll weight was usefull traits as a potential selective for breeding in early stage because of its biggest genetic variance coefficient and highest general heritability in the broad sense. The SPAD value of fruit branch leaves had significant relativity with seed cotton output（0.163*）、lint cotton yield（0.139**）、boll weight（0.148**） and the number of bolls per plant（0.167*）, which was considered as a referenced target for photosynthetic physiology breeding. Mid-parent heterosis of Nankang3 obverse F₁ in photosynthetic rate under saturated light was observed in three different environments. The photosynthesis characteristic of hybrid maybe belong to cytoplasmic inheritance, and should pay great attention to the selection of female parent with high photosynthesis characteristic. Owing the low light compensation point（LCP） and high light saturation point（LSP） possibly was the basis of heterosis in photosynthesis characteristic under different environment. The relationship of the chlorophyll b content and the chlorophyll a/b ratio were possibly affinity with the photosynthesis.5 The upper critical temperature of pollen germination on the stigma of Nankang3 male was distributed during 35℃～40℃, and of which Nankang3 reciprocal hybrids and their parents were during 40℃～45℃. The upper critical temperature of pollen tube grow in pistil for Nankang3 reciprocal hybrids and their parents were during 30℃～35℃. The mid-parent heterosis in pollen germination on the stigma of Nankang3 and mid-parent heterosis of obverse F1 and inverse F1 in speed of pollen tube grow in pistil was obversed. The heat tolerance of hybrids in reproduction had cytoplasmic effect of female. The 40℃temperature played most promoted action on the pistil growth, and secondly for 35℃and thirdly for 45℃. High-temperature treatment of 37/27℃which was treated 16 days before flowering affected development of stamen of little buts of which brachs area size were during 1.3×1.3～1.8*2.1cm in Nankang3 male and induced its male sterility, but not for hybrid and female parent.更多还原