【作者】 张勇；

【导师】 仲崇禄；

【作者基本信息】 中国林业科学研究院 ， 林木遗传育种， 2013， 博士

【摘要】 针对我国华南沿海地区木麻黄人工林生产面临适宜的遗传资源少，林分生产力下降、防护林功能减弱、优良无性系和新品种缺乏等现实问题，需要对我国主栽的木麻黄树种开展系统遗传改良研究和制定多世代育种计划，不断提供获得遗传增益的优良无性系或新品种，用于木麻黄生态防护林和商品林建设。本论文以我国主栽的短枝木麻黄、细枝木麻黄和粗枝木麻黄为试验材料，进行了木麻黄优良育种材料的选择、系统研究了木麻黄繁育系统、同时开展了木麻黄种内和种间杂交育种技术及子代测定研究、以及制定了木麻黄多世代长期育种计划等。论文主要结论如下：（1）以我国目前种植最广泛的3种木麻黄树种为材料，系统分析了其种源、家系和无性系的遗传变异特点，掌握了必要的遗传参数并对其开展了综合选育，获得了一批优良育种材料，为进一步杂交育种和多世代长期育种奠定了坚实基础。短枝木麻黄的种源/家系试验表明，4个地区种源的总体表现为亚洲引种区＞亚洲分布区＞非洲引种区＞大洋洲分布区，15个国家种源的总体表现为马来西亚＞中国＞印度＞关岛＞巴布亚新几内亚＞泰国＞越南＞贝宁＞斯里兰卡＞埃及＞汤加＞肯尼亚＞澳大利亚＞菲律宾＞瓦努阿图，通过指数选择和按10%的入选率，共选择出9个综合性状优良的家系；在树高、胸径、单株材积、主干分叉习性、主干通直度和保存率等6个性状获得的平均遗传增益分别是9.0%、3.9%、14.8%、1.2%、1.1%、18.2%；细枝木麻黄种源试验中，按20%的入选率，共有3个种源C11、C08和C20被选择为优良种源，其树高、胸径、单株材积、主干分叉习性、主干通直度和保存率等6个性状的平均遗传增益分别是21.7%、25.9%、76.6%、2.8%、10.7%和10.0%；粗枝木麻黄种源试验中，按20%的入选率，共有5个种源G03、G02、G19、G07和G25被选择为优良种源，其树高、胸径、单株材积、主干分叉习性、主干通直度和保存率等6个性状的平均遗传增益分别是2.1%、1.4%、2.2%、0.2%、0.2%和6.2%；在2个试验点，17个参试短枝木麻黄无性系的测定中，按20％的入选率，选育出编号17、21和20的3个优良无性系，其树高、胸径、单株材积、主干分叉习性、主干通直度和保存率等6个性状的平均遗传增益分别是6.5%、4.8%、10.9%、3.7%、1.5%和8.1%。（2）掌握了我国主栽木麻黄的繁育系统特征，包括短枝木麻黄的开花生物学、授粉生物学、交配系统等特性，获得了木麻黄繁育系统的一些关键基础数据和规律。在木麻黄繁育系统研究中发现，3种木麻黄都是雄性的比例大于雌性比例；3种木麻黄的花期具有明显的重叠，表明3种木麻黄的天然杂交在时间上是可能的；短枝木麻黄花药花粉数量771～1145粒、未授粉的雌花寿命长达28天，雌雄花部特征与风媒传粉相适应，最大限度保障了木麻黄的繁殖成功；短枝木麻黄在自由授粉状态下存在较严重的传粉限制，传粉限制值为0.39，传粉限制导致座果率和结实率降低，补充人工授粉能缓解传粉限制；3种木麻黄的种内和种间杂交的亲和性差异不显著，说明木麻黄种间没有明显的生殖隔离，有利于开展木麻黄种间的远缘杂交育种；短枝木麻黄雌雄同株的自交亲和系数为0.94，雌雄同株木麻黄花粉/胚珠比值约为572.5，自由授粉子代的异交率约为58.3%，自交完全亲和，在繁育系统上属于兼性异交类型；短枝木麻黄雌雄同株的自交子代表现出严重的近交衰退现象，说明在木麻黄杂交育种过程中需要严格控制共祖率，避免近交衰退。（3）研究木麻黄种间种内嫁接的亲和力，并利用嫁接技术对木麻黄亲本进行矮化、促花和盆栽，在此基础上发展了一种更高效、安全、便捷、可操作性强的木麻黄控制授粉杂交技术，并利用该技术开展了木麻黄种内种间杂交育种和进行了杂交子代的苗期和田间测定。木麻黄通过嫁接可矮化优树，促进开花，开花期缩短3－4年，可显著地缩短了育种周期。同种嫁接的成活率为87.0～91.4%，而种间嫁接成活率为36.0～45.0%，说明种内嫁接比种间嫁接有更高的亲和力，而属间嫁接亲和力为零；木麻黄授粉室控制授粉方法，使得木麻黄控制授粉的成本降低，而效率、安全性和可操作性大大提高。利用新的控制授粉方法，木麻黄的座果率由常规套袋授粉方法的7.0%提高到89.9%，结实率由常规套袋授粉方法的8.1%提高到51.8%；研究结果表明，在新的控制授粉方法中，授粉室内相对室外隔离袋内较低的温室和湿度有利于保持花粉活力，更高的花粉密度有利于减少授粉限制，同时授粉室避免了外界不利因素对授粉前后的影响，这些都是获得更高座果率和结实率的原因。利用获得的木麻黄控制授粉技术，开展了木麻黄种内和种间控制杂交育种，并对杂交子代进行了苗期测定和田间试验。结果表明利用经过选优的亲本进行控制授粉杂交，其杂交子代的生长表现明显优于作为对照的自由授粉子代，说明选择优良的亲本可显著提高杂交子代的遗传增益。（4）以我国种植面积最大的短枝木麻黄为例，制定了长期育种计划。根据前面研究获得的优良育种材料、掌握的木麻黄的生殖生物学特性、木麻黄嫁接矮化促花和授粉室控制授粉等技术，结合我国木麻黄发展需求，提出了木麻黄的多世代长期育种计划。育种计划包括了育种目标的确定、育种群体和核心群体的建立与管理、种内种间杂交的设计、无性系测定的方法、生产群体的建立等关键问题，最终提供优良杂交种子和无性系两种种植材料，用于建立生态防护和木材生产的木麻黄人工林。更多还原

【Abstract】 Degressive protective functions, declining productivity and shortage of superior clonesand new varieties for casuarina plantations in coastal areas of southern China are critical issuesthat need to be addressed. Developing novel crossing techniques and continuously providingnew superior clones and varieties of casuarinas with sustainable genetic gain for ecological andeconomic purposes through multi-generation genetic improvement could help address theseissues.In this dissertation, selection of breeding material, reproductive biology, hybridizationtechniques and hybrid progeny test, and long-term breeding program were studied inCasuarina equisetifolia, C. cunninghamiana and C. glauca. Main results were summarized asfollows:(1) Based on the available genetic materials of the three Casuarina species which havebeen planted extensively in China, genetic variation chacteristics of provenances, families andclones were studied, and some important genetic parameters were obtained to carry outmulti-trait index selection. Some superior breeding materials were obtained for implementingfurther cross-breeding program. Provenance and family trials of C. equisetifolia indicated thatthe overall performance of provenances from4broad regions was in the order: Asia IntroducedRegion＞Asia Natural Distribution Region＞Africa Introduced Region＞Australia/PacificNatural Distribution Region. The overall performance of provenances from15countries wereMalaysia＞China＞India＞Guam＞Papua New Guinea＞Thailand＞Vietnam＞Benin＞SriLanka＞Egypt＞Tonga＞Kenya＞Australia＞Philippines＞Vanuatu. Based on10%selectionratio,9superior families were obtained. The mean genetic gains in Height, Diameter at BreastHeight (DBH), Individual Volume (V), Axis Persistence (AP), Stem Straightness (SS) andSurvival Percentage (SP) were9.0%,3.9%,14.8%,1.2%,1.1%and18.2%, respectively. In provenance trial of C. cunninghamiana,3provenances, viz. C11, C08and C20wereconsidered superior provenances based on20%selection ratio, and mean genetic gains in thesix traits were21.7%,25.9%,76.6%,2.8%,10.7%and10.01%, respectively. In provenancetrial of C. glauca,5provenances, viz. G03, G02, G19, G07and G25were selected as superiorprovenances based on20%selection ratio, and mean genetic gains in the six traits were2.1%,1.4%,2.2%,0.2%,0.2%and6.2%, respectively. In clonal trials involving17casuarina clonesconducted at two sites,3clones, viz. No.17,21and20were selected as superior clones basedon20%selection ratio, and mean genetic gains in the six traits were6.5%,4.8%,10.9%,3.7%,1.5%and8.1%, respectively.(2) The reproductive chacteristics of C. equisetifolia, including floral biology, pollinationbiology, mating system, etc. were studied, and some key background knowledges and systemsof reproductive biology of casuarina were obtained.Based on field observations in three sample plots set up in seedling plantations, it wasfound that there was a higher proportion of male than female individuals in all the threeCasuarina species studied. There were obviously overlapping blooming periods among thethree species which suggested potential probability to produce spontaneous hybrids. Someimportant reproductive chacteristics were evolved to ensure reproductive success at the greatestextent, such as large amount of pollens (771-1145) per anther, long longevity of female flowers(28days) when unreceptive, and some floral features adaptive to anemophily pollination. Therewas evidence of pollination limitation (pollination limitation value0.39) when these casuarinaswere subjected to open pollination conditions, which resulted in low fruit set and seed set.According to experiment results, the pollination limitation could be overcome by supplementalartificial pollination. There were no significant differences in cross-compatibility betweenintraspecific and interspecific hybridization, indicating no reproductive isolation among thethree species. In monoecious individuals of C. equisetifolia, results showed that the index ofself-compatibility was0.94, pollen/ovule ratio was about572.5, outcrossing rate was58.3%,and selfing was completely compatible, therefore monoecious individuals of C. equisetifolia should be included in facultative xenogamy category. Selfing seedlings raised in nurseryshowed serious inbreeding depression, implying the necessity to avoid inbreeding throughcontrolling coancestry in the process of cross breeding of casuarinas.(3) Grafting affinities between and within species of Casuarina genus were studied, andgrafting technique was used for dwarfing, flowering promotion, and pot culture of parent trees.A new controlled pollination approach with high efficiency, high safety rate and ease ofoperation was developed. This approach was used to carry out intra-and inter-specifichybridization of casuarina, and hybrid progenies were measured in nursery and in the field.Grafting experiments showed that plus trees could be dwarfed and early floweringpromoted through grafting. The breeding cycle could be shortened by3-4years. It was foundthat the survival of homograft was87.0～91.4%, and heterograft36.0～45.0%, implyinghigher compatibility of homograft than heterograft. Based on the reproductive biologicalcharacteristics of the three Casuarina species, a new controlled pollination technique wasdeveloped. Using the new technique, fruit set and seed set of C. equisetifolia were increasedfrom7.0%to89.9%, and8.1%to51.8%respectively. According to the new technique,lower temperature and humidity environments would be advantageous in maintaining pollenviability. Pollination chamber could overcome pollination limitation by increasing pollendensity and minimizing disadvantageous impacts of external environments on pollination. Allthese factors were favourable for higher fruit set and seed set. Intra-and inter-specificcontrolled hybridization were conducted using controlled pollination technique developedabove, and hybrid progenies were measured in nursery and in the field. Results showed thathybrid progenies originated from selected parents presented better growth performance thancontrol of open-pollated progenies, implying that selected superior parents can improve geneticgains of hybrid progenies.（4）Proposed long-term breeding program of C. equisetifoliaBased on the reproductive biological characteristics, collected breeding materials and thenewly-developed controlled pollination technique coupled with the practical requirement on casuarina improvement, a long-term breeding program for casuarinas was proposed with aparticular focus on C. equisetifolia. In this program, clearly defined breeding objectives,establishment and management of breeding population and nucleus population, mating designsof intra-and inter-specific hybridization and clonal test were included. Finally two types ofplanting materials, improved hybrid seeds and clones, will be obtained for plantationestablishment for ecological protection and timber production purposes.更多还原