Centrosema breeding for acid tropical soils, with emphasis on efficient Ca absorption

Abstract

Glasshouse culture in a typical acid Oxisol showed that deep rooting and vigour in Centrosema macrocarpum (DC.) Benth and its hybrids with C. pubescens Benth depended on efficient root absorption of Ca, despite high A1 saturation. The most vigorous hybrids had 0.76% or more Ca in tip-leaf dry matter, and shoot/root ratios of 0.9 to 1.6. Sand cultures containing 4.5 ppm Al markedly increased P content of roots, a possible reaction for neutralizing Al effects. The glasshouse culture of large F2 populations allowed the selection of vigorous, acid-soil-tolerant hybrids which were later successful in field plantings.