Parent-progeny relationships between maize inbreds and hybrids:analysis of grain yield and its determinants for contrasting soil nitrogen conditions.

D´ANDREA, K ; OTEGUI, M.E.; CIRILO, A; EYHERABIDE, G.

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2013 vol. 53 p. 2147 - 2161

0011-183X

Most research in maize (Zea mays L.) parent-progeny relationships focused on heterosis for grain yield determination, whereas non-heterotic effects for traits other than grain yield remained less explored. Our objectives were to analyze (i) frequency distribution and phenotypic plasticity for 29 eco-physiological traits in different genotypic groups (6 inbreds and 12 hybrids) and environments, (ii) parent-progeny relationships for these traits, and variations in these relationships caused by contrasting growing conditions, and (iii) direct and indirect effects of traits measured in inbreds on hybrids grain yield determination. Genotypes were cropped in the field at two contrasting N levels during three growing seasons. Range in phenotypic plasticity was (i) similar for inbreds and hybrids, (ii) largest for traits as PGY and nitrogen use efficiency (NUE), and (ii) smallest for traits as thermal times and kernel weight. Inbreds phenotype was usually (26 traits) a good predictor of hybrids phenotype, but analysis of standardized data demonstrated that (i) for nine traits (e.g. PGY, kernel numbers) this relationship was exclusively driven by environmental effects, and (ii) for the other traits there was a true genetic control. A high correlation (r>0.26; P£0.024) was established between hybrids grain yield and twelve traits measured in inbreds, among which we distinguished NUE (r=0.36; P=0.002) and ear growth rate (r=0.50; P<0.001) for their high direct effect and participation in the indirect effect of other traits.