Assessment of aluminium tolerance in maize using a rapid screening procedure

Abstract

Routine testing for Al tolerance requires that screening procedures be both rapid and simple. Growth-chamber techniques, developed in the USA, show considerable promise in this regard and were used in this study to compare the Al tolerance of 10 maize cultivars and to test the reliability of several plant performance indices proposed in the literature. Seedlings were grown under controlled environmental conditions in complete nutrient solutions, with and without Al. Visual assessment of roots grown in the presence of Al facilitated separation of the cultivars into three groups. RS5205, SR52, CG4801 and PNR394 were classed as ‘good’; SSM2039, SNK2147, and SABI308 as ‘intermediate’; and A475W, RO422 and TX390 as ‘poor’. Visual assessments, total root length measurements and indices obtained using the primary seminal root provided measures of Al tolerance in good agreement with field performance. Topgrowth and root mass were poorly related to plant performance and relative indices obtained using root measurements in the presence and absence of Al were markedly inferior to indices obtained from Al solutions alone. The suggestion is made that screening could possibly be successfully performed using visual root ratings. Inclusion of standard genotypes would eliminate much of the subjectivity associated with such procedures.