Nutrient efficient genotypes in cassava: scope to substitute for chemical fertilizers and in C sequestration

Abstract

Though cassava is a climate resilient crop having innate physiologic ability to sustain under rising atmospheric temperature, escalating fertilizer prices and its marginal availability has resulted in imbalanced plant nutrition affecting tuber yield, soil health as well as farmers' income. Hence, an attempt was made to see the response of some selected nutrient efficient cultivars under different nutrient management practices in substituting for chemical fertilizers as well as on growth and yield attributes. The study over 5 years revealed a better scope for these genotypes in sustaining the productivity in low innate fertile soils like Ultisols. Screening 100 elite genotypes for their agronomic and physiological efficiency resulted in the selection of six K efficient lines, 3 each for edible and industrial uses. Evaluation of these genotypes at 4 levels (0, 50, 100, and 150 kg ha-1) of K for 3 consecutive years and computation of NUE parameters and physiologic parameters other than tuber yield, tuber quality, drought and mosaic tolerance and plant architecture resulted in identifying Aniyoor (edible) and 7 III E3-5 (industrial) as K efficient. These genotypes could perform better at K50 and K0 at which the root biomass and LAI supported their efficacy to scavenge the fixed native soil K and its better utilization. Screening 300 land races resulted in the identification of fifteen NUE lines. Experiments with three NPK efficient lines viz., Acc. No. 906, Acc. No. 766 and Acc. No. 905 indicated higher potential of Ac. No. 906 in low input management (soil test based) and in higher C sequestration.