薄壳山核桃种质资源多样性及果实品质评价研究

Pecan is one of the world's most important and valuable fruit tree with very high economy value, especially of high oil content in fruit, with good nutrition value similar with olive. It is very suitable for large scale cultivation as oil trees. However as a result of introduction and species conservation confusion, the present domestic pecan germplasm resources mixed a lot. This situation together with lack of systematic and suitable germplasm resources evaluation was very adverse to the breeding programs and other researches. This study plan to use biological characteristics observation and molecular marker study to classify the diversity of Chinese-grown pecan germplasm, and at the same time evaluate fruit quality on the basis of previous research. Theoretically, proved the phenological period, fruit and other important biological characters of Chinese-grown pecan germplasm, elucidate the genetic relationship between breeds and with other hickory, analysis and evaluation fruit quality between different varieties, to provide experimental basis for development and utilization of Chinese-grown pecan germplasm resources. In practice, through systematic evaluation and comparison analysis, selected a group of suitable pecan germplasm for domestic cultivation and breeding programs, and 1～2 new pecan varieties with good fruit quality and strong adaptability.

薄壳山核桃是世界上最重要、最有价值的干果树种之一，具有很高的经济价值，尤其是果实含油量高，营养价值可与橄榄油媲美，非常适合做为油用林木大面积栽培。然而由于引种及品种保存混乱，目前国内种质资源鱼目混杂，缺乏系统的种质资源评价，对育种及其他研究工作的开展极为不利，相关的系统的果实品质评价缺乏。本研究拟在已有研究基础上，通过生物学特性观察和分子标记研究我国薄壳山核桃种质资源的多样性，同时对果实品质进行全面的评价。从理论上，探明我国薄壳山核桃种质资源的物候期、座果率等重要生物学性状，阐明品种间遗传关系及其与该属其他种的亲缘关系，分析和评价不同品种的果实品质情况，为我国薄壳山核桃种质资源的开发利用提供实验依据；从实践上，通过系统评价和比较分析，筛选出一批适合国内栽培的薄壳山核桃种源和育种材料，选育出1～2个果实品质好且具有较强适应性的国产薄壳山核桃新品种。

对现有的薄壳山核桃种质资源及果实品质进行研究和评价，可以更加准确的反映目前种质资源的利用潜力，有利于筛选出适宜中国栽培的优良薄壳山核桃品种。本项目通过生物学特性观察调查了21个薄壳山核桃品种的发芽特性、18个薄壳山核桃品种的开花特性、9个薄壳山核桃的发育特性；Pawnee品种的果实动态发育特性观察结果表明花后145d～155d之间大部分性状，尤其是决定果实品质、卖相的关键性状均达到最优值。通过ISSR和SSR分子标记研究了77份薄壳山核桃的遗传多样性，筛选出10个ISSR引物和8个SSR引物适合于薄壳山核桃遗传多态性分析及品种鉴定；聚类分析表明了薄壳山核桃和其他山核桃具有明确的遗传差异，Carya cathayensis 与薄壳山核桃属于同种属，两者具有很近的亲缘关系，而Juglans nigra (Juglans species)与其他的品种亲缘关系较远。通过果实品质评价研究了18份薄壳山核桃成熟果实品质，结果显示不同品种间果实品质差异较大，且引入中国后果实品质发生了较大的变化；对Pawnee品种的果实品质动态研究结果显示果实发育早期至中后期（95d-145d）是薄壳山核桃果实品质积累的关键时期。