Improving water use and accelerating breeding pipelines in Mexican avocado

墨西哥是世界上最大的鳄梨生产国，哈利斯科州是第二大鳄梨生产国。这种水果的全球贸易使牛油果成为墨西哥最有价值的农产品，这对成千上万从事其种植和供应链的农民和工人的生活质量产生了重大影响。水的可用性对鳄梨的生长和产量有重大影响，鉴于墨西哥面临的日益严重的水危机，这是一个主要问题。对水的需求如此之大，以至于地下水供应正在枯竭，干旱频繁发生，哈利斯科州的大片地区受到严重干旱的影响。鉴于这种作物对墨西哥的经济重要性，因此，育种计划的重点是提高鳄梨对水分胁迫的适应能力，提高每滴水的产量，这一点至关重要。墨西哥农业食品议程的政策制定者已经认识到这一点，决定培育适应不同农业生态条件的鳄梨品种是一个优先问题。鳄梨拥有丰富的遗传资源，可用于实现这一目标，但利用这些资源存在主要障碍。这是因为牛油果是多年生物种，幼期较长，这意味着通过传统育种，可能需要数年时间才能在具有商业特征的种质中分离出突出的特征。此外，虽然在不同的加入方面有重要的遗传资源，但基因组学资源支持不足。例如，目前还没有基因组序列和有限的基因表达数据。该项目旨在解决这些障碍，并为推进鳄梨育种计划提供一个平台。由于提高对水分胁迫的抵御能力是育种者的关键性状和目标，作为案例研究，我们将重点关注利用与其他植物合作获得的知识提高水分利用效率（WUE）和抗旱性。为了解决这些问题，我们的项目有三个目标。第一个重点是减少牛油果树开花所需的时间。作为概念的证明，我们将利用生物技术来增加开花积极调节因子的表达，未来的目标是开发非转基因方法来实现这一目标。我们的第二个目标是着重于识别和表征牛油果添加与改善用水。在这里，我们将产生一些基因组资源，以使这一领域的分子研究，目前受到限制，由于缺乏序列信息。最后，我们将专注于促进基因编辑技术在鳄梨中的应用，当结合我们更快开花的目标时，应该会大大加快鳄梨的育种管道。这项研究及其开发的资源将向牛油果研究和育种界公开，并将对推进育种步骤有价值。这将有助于有针对性地改善这种墨西哥作物，并通过改善用水，还应减少这种作物的用水需求，从而减轻墨西哥淡水供应的压力。

Mexico is the world's leading avocado producer and Jalisco is the second largest avocado producing state. The global trade in this fruit makes avocado Mexico's most valuable agricultural product and this has a major impact on the the quality of life of thousands of farmers and workers employed in its cultivation and supply chain. Water availability has a major impact on avocado growth and yield, which is of major concern given the growing water crisis facing Mexico. Water demand is so great that ground water supplies are being depleted and droughts are frequent, with large areas of Jalisco being affected by severe drought. Given the economic importance of this crop to Mexico, it is therefore vital that breeding programs focus on improving the resilience of avocado to water stress and improve the amount of crop per drop. This has been recognized by policy makers in the Mexican Agri-Food Agenda, determining that the generation of varieties of avocado adaptable to different agro-ecological conditions is a priority issue. Avocado has a wealth of genetic resources that could be used to achieve this aim yet major barriers exists to utilising these resources. This is because avocado is a perennial species with a prolonged juvenile stage, meaning that it can take years to segregate outstanding characteristics in germplasm with commercial characteristics by traditional breeding. Further, whilst there are significant genetic resources in terms of different accessions, this is poorly supported by genomics resources. For example, as yet there is no genome sequence and limited gene expression data. This project aims to address these barriers and provide a platform for advancing avocado breeding programs. As improved resilience against water stress is a key trait and aim for breeders, as a case-study, we will focus on improving water use efficiency (WUE) and drought tolerance using knowledge gained from work with other plants. To address these issues, our project has three objectives. The first is focused on reducing the time that is required for avocado trees to flower. As a proof of concept, we will utilise biotechnology to increase the expression of a positive regulator of flowering with the future aim of developing non-transgenic approaches to achieve this. Our second objective is focused on identifying and then characterising avocado accessions with improved water use. Here, we will generate a number of genomic resources, in order to enable molecular research in this area, which is currently limited due to a lack of sequence information. Finally, we will focus on facilitating the use of gene editing technologies in avocado, which when coupled to our goal of faster flowering, should significantly accelerate the breeding pipelines of avocado. This research and the resources it develops will be made publicly available to the avocado research and breeding community and will be valuable for advancing breeding steps. This will enable targeted improvement of this Mexican crop and through improved water use, should also reduce the water requirements of this crop, and so reduce pressure on Mexico's freshwater supplies.