澳洲野生綠豆表現型與環境因子間的關聯

Abstract

綠豆是一種重要的豆類作物。綠豆會與根瘤菌共生進行固氮作用，因此相當適合作為綠肥植物在輪作系統期間種植，恢復土壤肥力。種植綠豆目前所遇到的逆境有鹽害、高溫、乾旱、淹水等，在種植時往往會需要挑選得以應對特定逆境的品系。作物的育種時常會從作物的野生品系著手，尋找那些在野外歷經天擇、已具備抗逆境特性的個體。我們針對澳洲野生綠豆(Vigna radiata var. sublobata) 的族群結構進行分析，並藉由溫室實驗測量這些野生綠豆性狀、探討其性狀與氣候因子之間的關聯。研究結果顯示澳洲野生綠豆在基因上大致可以分為東、西澳兩大族群。這兩群的野生綠豆在性狀上具有顯著差異，其中包含：果莢大小、種子大小、葉片裂緣程度、生長習性、莖寬、節間數量及開花時間，同時這些性狀在與氣候因子的關聯性分析中表現出顯著相關。結果顯示乾旱較長的西澳地區，其綠豆的表現型具有較少裂緣的葉片、偏向直立型的生長習性、較細的主莖、較少節間數量、較早的開花時間、以及較大的果莢跟種子。從我們的結果可以了解澳洲野生綠豆性狀可能受到當地氣候長久下來的天擇，因而具有不同的表現型。

Mungbean is one of the most important legume crops in the world. The mungbean’s symbiotic relationship with rhizobia could perform nitrogen fixation and maintain soil fertility in the crop rotation system. Due to the salinity, high temperature, drought, and waterlogging, the accession of mungbean used must be considered to overcome the stress. The breeding of crops often starts with the wild plants which have been selected by the habitat environments and have the resistance to stress. With wild mungbean accessions from Australia, we examined their population structure, measured several traits, and analyzed the correlation between traits and environmental factors. Our results showed that mungbeans in Australia could be genetically classified into two genetic groups, one in Western Australia and one in Eastern Australia. There were significant differences between the two groups’ traits, which included pod size, seed size, lobed leaflets, growth habits, stem width, internode number, and flowering time. The wild mungbeans from Western Australia were with fewer lobed leaflets, erecting plant growth habits, thinner main stems, less internode number, early flowering, and higher yields. Also, these traits were significantly correlated with environmental factors. The different phenotypes of wild mungbean in Australia may result from the long-term selection in the environments. These findings may provide scientists with inspiration for breeding.