Root system architecture phenotyping under field conditions in a maize diallel mating design

GALIZIA, L.A.; D'ANDREA, K.E.; MUNARO, E.M.; CIRILO, A.G.; OTEGUI, M.E.

Santa Fe

Congreso; XXXIII Reunión Argentina de Fisiología Vegetal; 2021

IAL-UNL

Root system architecture has been highlighted as a promising trait for achieving a Second Green Revolution. However, little is known about its genetic control and variability, specially under field conditions. The objectives of this work were (i) to characterize root length in two contrasting genotypic groups (GG; inbreds and hybrids) at the beginning and end of the critical period for maize grain yield determination and (ii) to quantify its heterosis level.Genetic material: a diallel mating design, comprising six inbred lines with contrasting characteristics and the fifteen derived F1 hybrids (excluding reciprocals), was evaluated. A field experiment was carried out during de 2013/14 season, under irrigated and fertilized (200 kg N ha-1) conditions, in a randomized complete block design layout with three replicates.. A soil core of 5 cm diameter to 2 m depth was obtained for each plot at each sampling date (V14 and R2). The samples were divided into 20 cm layers, washed and scanned to determine root length. When comparing total root length of the GG significant differences were found only at the R2 sampling, mainly due to the greater deepening of the hybrids. At R2, the mean % heterosis was 42% for the whole root system and of 79% for the 120-200 cm layer. Root length at R2 at the 120-200 cm layer was positively correlated with grain yield (r=0,43, p