NUTRIENT EFFICIENCY OF DIFFERENT CROP SPECIES AND POTATO VARIETIES - IN RETROSPECT AND PROSPECT

Different plant species and potato cultivars differed in nutrient use efficiency. Earlier studies indicated that potato cv. Kufri Pukhraj was the most N, P and K efficient cultivar among released cultivars tested in the absence as well as presence of green manure. The efficient cultivars gave higher tuber yield under N, P and K stress (i.e. with less dose of N, P and K fertilizer) and had higher agronomic use efficiency (AUE) than less efficient cultivars. The main cause of higher nitrogen efficiency in the presence of green manure was the capacity of a genotype to use/ absorb more N per unit green manured soil. The variation in phosphorus and potassium efficiency of different potato cultivars was due to both their capability to use absorbed P and K to produce potato tubers (PUE) and to their capacity to take up more P and K per unit soil (NUE). Further comparison of nutrient (N, P & K) efficiency of promising potato hybrid JX 576, now released as Kufri Gaurav, with Kufri Pukhraj revealed that hybrid JX 576 is more N, P and K stress tolerant than Kufri Pukhraj. Its higher efficiency was mainly because of its better utilization of absorbed nutrients (N, P and K) for potato production than other cultivars. The higher expression of ammonium transporter, cytochrome oxidase and asparagine synthetase in leaves can be used as parameters to screen potato genotypes for high metabolism, utilization, transport and storage of N. This review brings out the need to establish linkage of nutrient efficiency with root and shoot parameters/DNA markers/genes.