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，淡季粒用高粱的种植面积颇为广阔，其中大部分区域位于塞拉多（Cerrado）——这一巴西生物群落（biome）类似稀树草原，以高酸度和含量达到植物毒性水平的可溶性铝为典型特征。铝元素是制约高产的关键限制因子。本研究旨在针对铝耐受性开展高粱杂交种的表型鉴定。本试验于2014年4月4日至5月30日在巴西农牧业研究公司玉米与高粱研究所（Embrapa Maize and Sorghum）的生长箱中开展，共评估了18个杂交种，所用营养液的三价铝离子（Al³+）浓度分别为0 μM和27 μM。以ATF 13B（铝敏感型）和ATF 14B（耐铝型）品系作为对照品种。基于120小时净根生长量（NRG120）、168小时净根生长量（NRG168）以及168小时相对净根生长量（RNRG168），可有效区分耐铝杂交种与敏感杂交种。高铝饱和度可使根系生长降低70%。杂交种BRS 310与BRS 373在营养液培养条件下对铝胁迫表现出耐受性；杂交种BRS 330被归为中间类群，根系生长降幅约为50%；其余杂交种均表现为铝敏感型，根系生长受到显著抑制。