Doctoral Dissertation Research: The Fate of Maize Genetic Resources in Chiapas, Mexico

作物起源和进化中心的遗传变异性丧失或遗传侵蚀已被确定为社会和农业文化变化的负面结果。 改进我们管理农业遗传资源损失的方法的一个关键步骤是评估造成这种侵蚀的程度、条件和趋势。迫切需要开发更大空间尺度的研究工具，以评估影响遗传资源的社会和环境进程的范围，并确定有效保护的机会。墨西哥是世界三大作物之一的野生和栽培玉米资源的主要中心，但玉米遗传资源的生存受到全国各地发生的景观变化的威胁。 正是在这种背景下，并与改善作物遗传资源保护战略的最终目标，该项目将调查气候变化和土地转换对墨西哥南部恰帕斯州玉米多样性的影响。直到最近，农业现代化对遗传变异性的丧失构成了最大的威胁。 再加上目前的土地转换模式，未来的气候变化可能会超过这些影响，在规模和程度上，危及高度适应性的生态位的完整性，大多数传统的玉米地方品种生长。 结合传统的实地数据与当前的空间分析技术，玉米多样性和土地利用模式之间的关系将通过使用空间分析方法，加上玉米多样性和土地利用的时间序列数据库进行检查。 一个特别强调的是放在建模的生物物理和社会经济的限制，可能会产生负面影响的现有多样性的玉米品种，鉴于预期的气候和土地利用/土地覆盖的变化。模型将采用空间视角。该项目将利用这些信息来确定优先保护区，并将产生一个土地利用模式，以促进今后的保护工作。 玉米遗传资源作为育种家具有重要价值的性状库，是当前和未来粮食生产的资源。 保护作物遗传资源已成为国际当务之急，并列入《生物多样性公约》的任务规定。 到目前为止，理解和科普遗传侵蚀的努力受到了阻碍，缺乏模型，这些模型将这些因素整合为景观水平，而是集中在两个相反的空间尺度：作物多样性和农民选择的微观研究，以及作物-气候关系的全球或半球研究。 国家以下一级的研究可有助于整合这些数据，从而了解在各种尺度内发挥作用并相互作用以维持作物多样性的因素。 对作物遗传资源保护领域的研究人员来说，一个特别的挑战是为一个区域的生境制定可持续的管理模式，使这些资源所需的生物物理特性与人力资源需求相适应。 该项目将开发数据库，理论和方法来应对这一挑战。 该项目是在作物进化基础研究方面迈出的重要一步，也是对遗传资源保护理论和设计的重要贡献。 确定不同类型玉米的有效环境和采用的方法可用于确定世界其他地区作物保护的优先区域，也将有助于制定更有效的监测玉米多样性的取样战略。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Loss of genetic variability, or genetic erosion, in centers of crop origin and evolution has been identified as a negative result of social and agricultural cultural change. A key step in improving the way we manage the loss of genetic resources in agriculture is to take stock of the extent, condition and trends that cause this erosion. A critical need is to develop research tools for larger spatial scales to assess the scope of social and environmental processes that affect genetic resources and identify opportunities for effective conservation. Mexico is the primary center of wild and cultivated maize resources, one of the world's most three important crops, but the survival of maize genetic resources is threatened by landscape changes taking place across the country. It is against this background, and with the ultimate goal of improving crop genetic resource conservation strategies, that this project will investigate the effects of climate change and land conversion on maize diversity across the state of Chiapas in southern Mexico. Until recently, agricultural modernization posed the greatest threat to the loss of genetic variability. Coupled with current patterns of land conversion, future climate change may surpass these effects, in both magnitude and extent, by endangering the integrity of the highly adaptive ecological-niches where most traditional maize landraces are grown. Combining traditional field data with current spatial analytic techniques, the relationship between maize diversity and patterns of land conversion will be examined through the use of spatial analytic methods coupled with a time-series database of both maize diversity and land use. A special emphasis is placed on modeling the biophysical and socio-economic constraints that are likely to negatively impact the existing diversity of maize varieties in view of expected climate and land-use/land-cover changes. Modeling will adopt a spatial perspective. The project will apply this information to identify priority zones for conservation efforts, and will generate a model of land use to promote conservation efforts in the future. As a reservoir of traits of great value to breeders, maize genetic resources are a resource for both present and future food production. Conserving crop genetic resources has been adopted as an international imperative and is included in the mandate of the Convention on Biological Diversity. Thus far, efforts to understand and cope with genetic erosion are hampered by the lack of models that integrate these factors as the landscape level, focusing instead on two opposing spatial scales: micro-level studies of crop diversity and farmer choice, and global or hemispheric studies of crop-climate relationships. Research at the sub-national level could help to integrate these data, resulting in an understanding of the factors that operate within, and interact across, the various scales to maintain crop diversity. A particular challenge for researchers in the field of conservation of crop genetic resources is in developing sustainable management models for a region's habitats, in which both biophysical specificity required by these resources and human resource needs are made compatible. This project will develop databases, theory, and methodology to address this challenge. The project represents a major step forward in the study of the basis of crop evolution and an important contribution to the theory and design of genetic resource conservation. The identification of effective environments of different types of maize and the methodology employed could be used to identify priority zones in crop conservation in other regions of the world and would also be helpful in the development of more efficient sampling strategies for monitoring maize diversity. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.