Variability for root and shoot traits in a maize population grown in hydroponics and in the field and their relationships with vertical root pulling resistance

Strength of maize (Zea mays L.) root system can be estimated by vertical root pulling resistance. However, this measurement is both laborious and destructive. Hence, it would be desirable to identify related traits whose measurements are easier and non-destructive. Objectives of this research were to study the variability of a population for root and shoot traits in hydroponic culture and in the field and to evaluate their relationships with vertical root pulling resistance. F 3 families derived from the single cross Lo964 x Lo1016 were evaluated together with the two parental inbreds in hydroponic culture (171 families) and in three field environments (118 families) In hydroponic culture, differences among F 3 families were highly significant for all traits and transgressive segregation was always found. Heritability ranged from 50 to 85%. A statistically significant association was observed only between seminal root weight and shoot weight (r = 0.72 ** ). In the field, differences among F 3 families across environments were highly significant for all traits and transgressive segregation was always found except for plant height and pollen shedding date. Heritability for vertical root pulling resistance was 72%, while for other traits heritability ranged from 56 to 91%. Associations of vertical root pulling resistance vs. both hydroponic and other field traits were biologically negligible even when statistically significant. It can be concluded that, despite the large variability available in the population, indirect selection for hydroponic traits would not be of benefit in improving vertical root pulling resistance under the field conditions studied.