关键词: 红壤, 柱花草, 磷效率, 基因型差异

Abstract: Stylosanthes guianensis is one of the most important leguminous pasture crops in the tropicand subtropic areas of South China,but its growth potential in low-P acidic red soil has not been fully explored.Soil pot experiments with thirteen different Stylosanthes guianensis genotypes were conducted to investigate the genetic variability of this crop in P efficiency.It was found that great genetic variability existed within the tested genotypes when they were grown on a low-P acidic red soil.According to the differentgrowth responses,the tested Stylosanthes guianensis varieties were distinguished into wild type, culturaltype and P-efficient type.No significant difference in P content was observed among the tested genotypes atthe same P level.This implies that the adaptability of different genotypes to low-P stress was not reflectedby P concentration in plant.Comparing P uptake and P utilization efficiency by calculating P uptake ratioand P efficiency ratio,we found the former was more important to P-efficient genotypes.

Key words: Red soil, Stylosanthes guianensis, P efficiency, Genotypic variation