Changes in the stratification and spatial distribution of the banana (MusaAAA cv. Grand Naine) root system of poor, regular, and good developed plants

In an attempt to explain the difference in banana (Musa AAA cv. Grand Naine ) plants with poor, regular, and good development, their root stratificatio n and spatial distribution was determined in Costa Rican field conditions. Samples were taken from soil blocks at 0 to 30, 30 to 60, and 60 to 90cm di stances from the pseudostem, and at every 15 cm depth, from 0 to 120 cm in non-flowering plants that were 180-190cm high. The plant development sites did affect the proportion of fresh thick roots (> 5mm-d) as follows: 49, 63 , and 56% in plants with poor, regular, and good development, respectively. The lateral distribution of thick and fine (1 to 5 mm-d) roots and root ha irs was affected by the horizontal distance from the pseudostem. The total percentage of roots decreased as horizontal distance increased in any plant development. Soil depth affected the distribution of every fresh root type throughout the soil profile. The total fresh root weight in the excavated area (0-90cm from the pseudostem and 0 120cm depth) was 0.95, 0.9, and 0.76 kg, for poor, regular, and good developed plants, respectively. Therefore, the explanation for regular and good plants more likely was the depth of th e root system, which reached up to 120cm deep, while in the poor plants the roots reached only 75cm deep. Additional studies that relate the root stra tification with crop yield are encouraged.