中国竹节草种质资源遗传多样性研究与特异种质选育

Chrysopogon aciculatus (Retz.) Trin. is one of the most important warmseason turfgrass and one of distribution center in China, widely distributed in tropical regions of South China. As a high quality turfgrass, C. aciculatus has many fine characteristics and rich genetic variation. But the studies on genetic diversity and resistance identification were very little, which limits its wide utilization and adequate protection. In order to meet the urgent need for both landscape of South China and the quick resistance identification of C. aciculatus, the following work will be conducted with C. aciculatus based on the early stage work: (1) The methods of resistance identification of C. aciculatus have been improved; (2) In theory, the biological characteristics and genetic diversity of C. aciculatus would be studied based on turf quality, reproductive performance, phenology, resistance, and provided the basis for developing protection strategy of wild germplasm, sustainable use, and improvement of C. aciculatus; (3) In practice, the specific accessions with different excellent characteristics would be screened by compared with released cultivars, and selected 5-7 domestic C. aciculatus accessions with excellent turf quality, high organs reproductive ability, strong resistance, and good adaptability. The selection of specific C. aciculatus accessions with many superior characteristics will provide the cheap and high quality plant materials for the development of landscape of international tourism Island of Hainan and then extending to South China.

竹节草是一种重要的暖季型草坪草，我国作为竹节草分布中心之一，广泛分布于华南热带地区，具有许多优良特性和丰富的遗传变异。但其遗传多样性和抗性鉴定方面研究甚少，尚未得到充分的保护和利用。本项目针对南方园林绿化过程中迫切需要优质抗逆的草坪草以及快速有效的抗性鉴定方法这一现状，在广泛收集竹节草种质资源及已有研究基础上，改进竹节草种质资源抗性鉴定方法，通过对竹节草种质资源的生物学特性和遗传多样性研究，对竹节草种质资源进行全面评价，从理论上，探明竹节草重要坪用性状、器官繁殖性能、物候期、抗（寒、旱、盐、酸、荫）性的变异及其特点，为竹节草野生种质资源保护策略制定和遗传改良利用提供科学依据；实践上，通过与对照草种比较分析，筛选出一批特异的种质资源，选育出5-7 个坪用价值优、器官繁殖性能高、抗性强且适应性好的国产竹节草特异种质，以服务于海南国际旅游岛的绿化建设，继而推广到华南地区进行国土绿化和景观建设。

本试验以89份竹节草[Chrysopogon aciculatus (Retz.) Trin.]种质资源作为试验材料，其中包括国内5个省市的材料，研究结果表明：.1、形态多样性研究.本研究选取16个外部形态指标，对87份竹节草种质进行研究。结果表明：竹节草种内形态变异范围为9.09%-90.95%；草层越高，生殖枝越高；花序密度越高；87份种质可被分为三个类型。.2、DNA分子多样性研究.应用ISSR和SRAP标记对86份种质进行检测，结果表明：25对SSR引物、25条ISSR引物和30对SRAP引物中分别共扩增出90条、283条和627条谱带，平均每个引物扩增出3.3条、10.9和20.9条带，PPL达92%、94%和92%，86份种源聚类分别聚为二、三和四大类，GSC范围为0.51-0.96、0.52-0.93和0.56-0.91。.3、种质抗性评价.在对84份种质抗寒性鉴定方面，抗寒性强的品系有CA12、CA22、CA65、CA67、CA69和CA84。在对69份种质抗旱性鉴定方面，水分利用效率变异范围为0.28%-0.95%；抗旱强的品系CA28、CA59和CA66。在对83份耐酸性鉴定方面，在1.9 mmol·L-1的铝处理后，变异系数范围是16.2%-42.3%，耐铝品系有CA67和CA74；在耐盐性鉴定方面，64份种质经245 mmol·L-1的盐处理后，不同指标间的变异系数范围为20.6%-43.4%，耐盐品系有CA20和CA29。在对83份种质耐荫性鉴定方面，耐荫性强的有CA01、CA26和CA50。.4、繁殖器官响应差异研究.在营养生长特性方面，88份种质变异系数平均为23.3%，匍匐茎快速繁殖型种源为CA61。在生殖生长特性方面，平均变异系数达29.3%；种子产量高的为CA45。.5、指纹图谱的构建.利用ISSR827标记建立了6个优良品系的DNA 指纹图谱，从分子的角度将它们区分开来。