Study on Present Status of Plant Germplasm Resources Conservation and Countermeasures

Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well as one of the countries with most abundant plant resources and the highest biodiversity. Strengthening research in the conservation and utilization of plant germplasm resources is of significant value and importance. In this study, the present status of conservation, utilization, and existing problems of plant germplasm resources in China and around the world were reviewed; further, through analyzing measures taken by global countries for plant germplasm resources protection, countermeasures for plant germplasm resources conservation in China were also presented from three aspects, namely, collection and conservation, information network construction and national legislation and policies.

Characteristics and Warning Indexes of Rice Seeds Viability Loss During Storage at 45℃ Constant Temperature

Seed aging characteristics of rice was investigated in this study. Seeds of 34 japonica rice (O-ryza sativa subsp. japonica) varieties were held at 451 constant temperature. Changes in seed viability and seed vigor during aging process were measured to study seed viability-losing characteristic and to determine warning index for seed viability loss. As a result, seed viability survival curves were obtained across different rice accessions at 45℃ constant temperature. The curves appeared to be contra-sigmoid survival curves. The loss of seed viability in the aging process consisted of two phases. The first phase took a long duration, in which the viability of vigorous seeds declined slowly. In the second phase, seed viability declined rapidly. It was obvious that seed viability declined inconsistently during storage. It also showed that seed germination was prolonged and the seedling was significantly weakened before the coming of the rapid declining phase of seed viability. These two parameters could be used to indicate seed quality during storage. The rate of compatibility of tests (RCT), coefficient of variation (CV), vigor of seedling, the day the seeds start to germinate could be used as warning indexes to indicate overall quality of a mass of accessions. These warning indexes could also be used in monitoring the viability of seeds stored in the seed genebank.

Advances in Origin,Evolution and Classification of Pyrus L.

China is not only one of the origin centers of Pyrus L.,but also the earliest birthplace of Pyrus L.in the world.This paper reviews the evolution of Pyrus L.from the aspects of leaf edge morphology,inflorescence and fruit type,and summarizes the research progress of classification and species distribution of Pyrus L.,which is of great significance for the protection,evaluation and utilization of germplasm resources.

Research and Conservation of Forest Genetic Resources in China

The present situation of forest tree genetic germplasm resources research and conservation in China is introduced which including the background, decision-making of conservation strategies and principles, the plan of area division and tree species classification, the sample strategy of germplasm conservation, the advances in conservation pattern and related technologies research, the achievements of germplasm conservation and utilization in China, and the problems to be solved. The recent achievements a...