Brittle-snap susceptibility in a RILs population of maize (Zea Mays L.): phenotypic and genotypic analysis.

MANDOLINO, C.; D'ANDREA, K.E.; OLMOS, S.; CERRI, A.M.; CIRILO, A.G.; OTEGUI, M.E.

Mar del Plata

Workshop; II Workshop Internacional de Ecofisiología de Cultivos.; 2013

FAUBA-FCAUNMP-INTA

Winds stronger than 45 m s-´ are known to cause severe brittle-snap of maize (Zea mays L.), with stalks breaking near the uppermost ear node, particularly in crops undergoing active stem elongation immediately before anthesis. Breeding against this constraint is limited by the lack of accurate methods for simulating predisposing conditions. The aim of this work was to (i) study the genotypic variation in maize susceptibility to brittle-snap, and (ii) evaluate its relationship with several morphometric and physiological traits. These traits were plant height to the uppermost ear and to the uppermost collar, estimated stem volume at ear and uppermost collar heights, stalk diameter at ground level, and growth rates between V11 and R2 (plant and ear). We phenotyped mentioned traits for a collection of 180 recombinant inbred lines (RILs) derived from two contrasting parental inbreds (B100: American semident; LP2: Caribbean-Argentine flint). Inbreds were sown in the field at three different sowing dates for avoiding the confounded effect of their variation in time to anthesis (surveyed during 2009-2010). The experimental layout was a completely randomized block design with two replicates. Stand density was 7 plants m-2, and plots had 10.5 m2. A severe wind storm took place on 23-Jan-2012, immediately before anthesis of the experiment. Stalk breakage ranged between 0 (28% of inbreds) and >50% damage (1.1% of inbreds, with a maximum of 55.6%), it was not normally distributed (P