Genetic analysis of root traits in maize

Abstract

-In many areas around the world, maize (Zea Mays L.) crops are affected by root lodging. Several authors have previously shown that associations of root and shoot traits enabled the prediction of the resistance of genotypes to root lodging. In this preliminary attempt to understand the genetics of these traits, a set of 100 recombinant inbred lines from a cross between élite lines 'F2' (early, susceptible to root lodging) and 'Io' (late, lodging resistant) was considered. This population was characterised for 152 RFLP loci and root system traits in one location and for 2 years. QTLs were mapped using the average over years. Genetic and environmental correlations, together with co-localisation of QTLs for several traits, revealed genetic linkages, and some probable pleiotropic effects, which could be interpreted in terms of within-plant growth competition phenomena. The (Villeneuve-lèz-Avignon)

QTL mapping of root angle in F₂ populations from maize ‘B73’ × teosinte ‘<i>Zea luxurians</i>’

“…The relationship between the remaining QTLs is currently unclear; further study is necessary. For root angle in maize, only a single QTL was identified by Guingo et al (1998) − using a set of recombinant inbred lines derived from a cross between "F2" × "Io", a QTL controlling the angle of root growth direction at internode 7 was found on chromosome 5 (bin 5.05). However, the relationship was not found in our study.…”

Meta-analysis of constitutive and adaptive QTL for drought tolerance in maize

“…Moreover, the secondary traits studied to identify QTL and analyze the response of maize to drought stress in recent decades have included anthesis-silking interval (ASI; Ribaut et al 1996;Welcker et al 2007) and root traits (e.g. seminal root number; nodal root number; root pulling force; primary root diameter, length and weight; and adventitious seminal root weight; Lebreton et al 1995;Guingo et al 1998;Tuberosa et al 2002b). In maize, it is well known that the most critical stage for yield losses due to drought is just before and during flowering; thus ASI can be a reliable and easily-scored indicator of the level of water stress, due to the major effect of water stress on delay of silking (Tuberosa et al 2002a).…”

QTL mapping and phenotypic variation for root architectural traits in maize (Zea mays L.)

“…While examination of the seedling root system is relatively easy, root traits in young plants may be poor predictors of mature root system architecture or plant performance (Zhu et al 2011). A few QTL for architectural traits have been identified in mature maize root systems, including those for adventitious root formation (Mano et al 2005), brace root whorl number (Ku et al 2012), and several crown root traits including number (Lebreton et al 1995;Guingo et al 1998;Liu et al 2008a;Cai et al 2012), diameter (Guingo et al 1998), angle (Guingo et al 1998), and length (Liu et al 2008a;Cai et al 2012). A more detailed analysis of QTL for architectural traits of mature maize plants would enable breeding of crops with improved stress tolerance.…”