Genotypic variation and relationships between seedling and adult plant traits in maize (Zea mays L.) inbred lines grown under contrasting nitrogen levels

Abstract

Genotypes with better root development have good nutrient acquisition capacity and may yield better under limited nitrogen (N) conditions and consequently can help reduce the N fertilization rate and hence mitigate some economic and ecological problems. This study focused on the genotypic variation among diverse maize inbred lines for seedling and adult plant traits under contrasting N levels. Seventy four lines were screened under high and low N levels in a climate chamber and in the field. High phenotypic diversity was observed for seedling and adult plant traits together with moderate to high broad-sense heritability estimates. Seedling total root length and root dry weight were significantly correlated with other root traits in maize. Of the adult plant traits evaluated in the field, the anthesis-silking interval and the leaf chlorophyll contents were significantly correlated with grain yield under both low and high N levels. In one location, the seminal root length was correlated with grain yield both under low and high N levels and the root dry weight was correlated with grain yield under high N. Selection indices based on secondary root traits along with grain yield could lead to an increase in selection efficiency for grain yield under N stress condition. By identifying lines with better root development, particularly lines with longer SRL, it may be possible to select inbred lines with higher grain yield particularly under low N condition.

Genome-wide association studies of doubled haploid exotic introgression lines for root system architecture traits in maize (Zea mays L.)

“…Most of the lines in the GEM-DH panel were BC 1 -derived, with an average percentage of recurrent parent (PHB47 or PHZ51) of 77.78%; this might explain the less extreme variation among GEM-DH lines compared to the Ames panel. The results in this study, however, were consistent with the findings of Abdel-Ghani et al [2]. Most of the other traits showed around 2-to 3-fold differences between the minimum and maximum values.…”

“…Nonetheless, Abdel-Ghani et al [2] found significant and positive correlations between seedling root and adult plant traits, indicating that more vigorous seedling growth might contribute to a higher grain yield. Root system architecture traits are highly variable among maize genotypes.…”

“…Selection for better root development may identify maize inbred lines with higher grain yield under low nitrogen (N) fertilization conditions [1,2]. Root growth, especially initiation and development of shoot-borne roots, as well as the amount of N taken up were found to be correlated with shoot growth and demand for nutrients [3].…”

Genotypic Variation in Seedling Tolerance to Aluminum Toxicity in Historical Maize Inbred Lines of Zambia

“…However, the high coefficient of variation resulting from spatial variation in the soils poses a challenge to field evaluation [17] and eventually affects the reliability of the results. Therefore, laboratory hydroponic studies of root traits offer another option if the laboratory results are correlated to field performance under the same stress conditions [17][18][19]. In maize, laboratory studies on seedling traits have been reported to be highly correlated to field performance for low nitrogen conditions [20], nutrient and water use efficiency [21], and weak correlation for aluminum toxicity [19].…”

“…Therefore, laboratory hydroponic studies of root traits offer another option if the laboratory results are correlated to field performance under the same stress conditions [17][18][19]. In maize, laboratory studies on seedling traits have been reported to be highly correlated to field performance for low nitrogen conditions [20], nutrient and water use efficiency [21], and weak correlation for aluminum toxicity [19]. Ouma et al (2013), using relative net root growth (RNRG) of maize seedling under aluminum toxicity, were able to predict 24% and 35% of field performance.…”