Tetraploid plants, including those induced from diploid barrel medic (Medicago truncatula Gaertn.) and the snail medic [Medicago scutellata (L.) Mill.], have the potential to increase vigor and leaf size to improve adaptation to environments with low and variable rainfall in Mediterranean climates. The growth of tetraploid lines induced from barrel medic cultivar Sultan‐SU was evaluated against the diploid parent line and a natural tetraploid snail medic cultivar Sava in field conditions in Adelaide, South Australia. In field conditions, tetraploid lines had up to 106% greater autumn biomass than Sultan‐SU, 58% larger seed weight, and a 127% increase in leaf area. In a controlled environment experiment, snail medic Sava was the only entry to show improved early season (assessed at 6 wk) shoot biomass and canopy cover under short days and low temperatures that were designed to simulate a late start to the growing season. An examination of fresh flower buds showed that the fertility and stability of induced tetraploid lines varied between lines and generations. Hardseed breakdown patterns differed among tetraploid mutant lines, with two lines having much harder seed than Sultan‐SU. Some tetraploid Medicago spp. produced greater early biomass and larger leaves than diploids. Increasing ploidy level provides plant breeders with a promising tool in the development of new cultivars better suited to future climate scenarios.

中文翻译：

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倍数对一年生紫花苜蓿物种活力，生产力和对气候变化的潜在适应的影响

四倍体植物，包括由二倍体桶状军医（Medicago truncatula Gaertn。）和蜗牛军医[ Medicago scutellata（L.）Mill。]，具有增加活力和叶片大小的潜力，以改善对地中海气候下降雨量少且变化多的环境的适应性。在南澳大利亚州阿德莱德的田间条件下，针对桶状军医品种Sultan-SU诱导的四倍体株系与二倍体亲本株系和天然四倍体蜗牛病菌Sava的生长进行了评估。在田间条件下，四倍体品系的秋季生物量比Sultan-SU高106％，种子重量高58％，叶面积增加127％。在受控环境实验中，蜗牛军医萨瓦（Sava）是唯一显示出改善的早季（以6周评估）的枝条生物量和冠层覆盖率的条目，其旨在模拟生长季节的较晚开始，并在短日低温下进行。对新鲜花蕾的检查表明，诱导的四倍体品系的育性和稳定性在品系和世代之间有所不同。在四倍体突变株系中，硬种子分解模式有所不同，其中两个品系的种子比苏丹-SU硬得多。一些四倍体苜蓿属。与二倍体相比，产生的早期生物量更大，叶片更大。倍性水平的提高为植物育种者提供了一种有前途的工具，使其可以开发出更适合未来气候情景的新品种。