Evaluation of grain sorghum hybrids for aluminum tolerance in nutrient solution

ABSTRACT. Sorghum (Sorghum bicolor L. Moench) is one of the most important cereal crops in the world. In Brazil, the acreage of grain sorghum during off-season is quite expansive. Most of this area is the Cerrado, a Brazilian biome that is similar to a Savannah and is characterized by high acidity and soluble aluminum at toxic levels for plants. The aluminum acts as a limiting factor in achieving high yields. The purpose of this work was to phenotype sorghum hybrids for aluminum tolerance. Eighteen hybrids were evaluated in a nutrient solution containing {0} or {27} µM Al3+. The work was carried out in a growth chamber at the Embrapa Maize and Sorghum, from April 4 to May 30, 2014. The lines ATF 13B (susceptible) and ATF 14B (tolerant) were used as check cultivars. Based on the Net Root Growth after 120 hours (NRG120), Net Root Growth (NRG168) after 168 hours and Relative Net Root Growth after 168 hours (RNRG168), it was possible to distinguish tolerant hybrids from susceptible ones. The high aluminum saturation reduced root growth by 70%. The hybrids BRS 310 and BRS 373 were tolerant to aluminum stress under nutrient solution. The hybrid BRS 330 was clustered in an intermediate group, with an approximately 50% root growth reduction. The other hybrids were susceptible with significant root reduction.

摘要：高粱（Sorghum bicolor L. Moench）是全球最重要的谷类作物之一。在巴西，季休期粒用高粱的种植面积规模可观，其中多数区域位于塞拉多（Cerrado）——这一巴西特有生物群落类似稀树草原，其特征为土壤高酸度与达到植物毒性水平的可溶性铝，而铝正是制约高产的关键限制因子。本研究旨在对高粱杂交种开展铝耐受性表型鉴定。试验以含0或27 μM Al³+的营养液为培养介质，对18个高粱杂交种进行评估，于2014年4月4日至5月30日在巴西农业研究公司玉米与高粱研究所（Embrapa Maize and Sorghum）的生长室内完成。试验以敏感株系ATF 13B与耐受株系ATF 14B作为对照品种。基于120小时净根生长量（Net Root Growth after 120 hours, NRG120）、168小时净根生长量（Net Root Growth after 168 hours, NRG168）及168小时相对净根生长量（Relative Net Root Growth after 168 hours, RNRG168），可有效区分耐铝杂交种与敏感杂交种。高铝胁迫可使根系生长降低70%。其中，杂交种BRS 310与BRS 373在营养液培养条件下对铝胁迫具有耐受性；杂交种BRS 330被归为中间类群，根系生长降幅约为50%；其余杂交种均为敏感型，根系长度出现显著降低。