遺傳歧異度對小米地方品系滲透逆境耐受性的影響

The Impacts of Genetic Variation on the Osmotic Stress Tolerance of Foxtail Millet Landraces

陳昶霖(Chang-Lin Chen) ； 張庭禎(Ting-Chen Chang) ； 張祐菱(Yu-Ling Chang) ； 林維怡(Wei-Yi Lin)

《作物、環境與生物資訊》 16卷4期 (2019/12) Pp. 208-219

https://doi.org/10.30061/CEB.201912_16(4).0003

摘要

水份逆境對作物產量影響甚鉅，提高耐受性已是重要育種目標。小米（Setaria italica L.）為小型穀類作物，屬於水份利用效率較高的C4植物，但遺傳歧異度對小米逆境耐受性的影響目前了解有限。本研究以158個來自臺灣及印度種原庫的小米地方品系為材料，以25% PEG6000的水耕系統模擬滲透逆境，檢測這些品系逆境耐受性的差異。結果顯示，所有品系在逆境處理7天後，株高和鮮重都顯著低於控制組，從中挑選耐受性較高、中等和較低的品系各10個，測試逆境回復能力，以及表型的關聯性，發現地上部和地下部的生長勢與逆境耐受性呈負相關，進一步檢測耐受性較高和較低的品系的氧化逆境指數，與其他測試品系相比，品系110的抗氧化酵素活性並未隨著逆境時間延長，甚至降低，葉表面溫度也沒有明顯升高，顯示該品系的耐受性較高。本研究揭露了遺傳歧異度對小米滲透逆境耐受性的影響，也鑑定出耐受性較高的品系，可作為未來育種和遺傳背景相關研究之參考。

關鍵字

小米 ； 滲透逆境 ； 遺傳歧異度 ； 逆境耐受性 ； 抗氧化酵素

並列摘要

The crop production was threatened by various kinds of stress, including water stress. Enhancing the stress tolerance is one of main breeding objectives. Foxtail millet (Setaria italica L.), a C4 crop species, has relatively high water use efficiency. But little is known about the impacts of genetic variation on millet stress tolerance. In this study, the hydroponic culture system containing 25 % polyethylene glycol (PEG 6000) was used to mimic the osmotic stress conditions. We used 158 millet landraces derived from Taiwan and the seed stock center in India as materials to study the variation of stress tolerance under osmotic stress conditions. The results showed that after 7-day treatment the plant height and fresh weight were significantly lower than those under normal conditions. Thirty landraces with high, medium or low stress tolerance were selected to test their ability of stress recovery. The correlation analysis suggested that the fresh weight and root length is negatively correlated with stress tolerance. Furthermore, we analyzed the activity of antioxidative enzymes in the landraces with high or low stress tolerance and found that the enzyme activity in landrace 110 was maintained at similar level or even decrease during the treatment. Its leaf surface temperature was also comparable to plants grown under normal conditions. It suggests that this line has higher stress tolerance. Our study revealed the effects of genetic variation on the osmotic stress tolerance of millets. We also identified the landraces with high tolerance. It provides useful information for breeding and further studies about the association of genetic background with millet stress tolerance.

並列關鍵字

Foxtail millet ； Osmotic stress ； Genetic variation ； Stress tolerance ； Antioxidative enzyme