Functioning of peanut (Arachis hypogaea L.) under nutrient deficiency and drought stress in relation to symbiotic associations

Abstract

Four peanut cultivars from Mozambique, Natal Common (NC) originating from South Africa, Mozambican landraces Bebiano Branco (BB) and Local (L) and Falcon originating from Zimbabwe (F), were grown in plastic pots for 13weeks. All cultivars have short cycle, NC and F being high-yield crops and bred for high-input agriculture, while BB and L, are used for low-input agriculture. The pots were filled with washed sand/vermiculite mixture, supplied with a slow release fertilizer osmocote 13:13:13 NPK. The relative growth rate (RGR) and various other growth parameters were studied in detail. The small-seeded cultivars NC and F showed a higher RGR compared to large seeded cultivars BB an L. The natural logarithm of the initial seedling weight (ISW) showed a negative correlation with the RGR and the final mean number of pods/plant and a positive correlation with the root weight ratio (RWR), whereas the RGR showed a positive correlation with the mean number of pods /plant and a negative correlation with RWR. The significant and negative correlation between in ISW and RGR resulted mainly from a negative correlation with leaf area ratio (LAR), via the morphogenetic effects of the specific leaf area (SLA) and leaf weight ratio (LWR). The cultivar Falcon allocated more dry matter to the pegs and pods, while the cultivar Local allocated more dry matter to the leaves and roots. A large root system in the cultivar Local may provide an advantage under limited soil moisture and nutrient resources.