Response of Indian mustard (Brassica juncea) germplasm grown under low nitrogen conditions

Brassicas are highly responsive to N application and require relatively high rates of mineral N fertilizers for optimum seed yields. Present study was carried out at the Experimental Farm of ICAR-National Bureau of Plant Genetic Resources, Pusa Campus, New Delhi, India during 2015-16 and 2016-17. Forty five accessions of Indian mustard were tested under three different nitrogen fertilizer rates i.e. Control (0 kg/ha), moderate (40 kg/ha) and optimal (80 kg/ha) to determine the performance of Indian mustard (Brassica juncea (L.) Czern.). The results showed that with increase in nitrogen fertilizer rate seed test weight, oil content, stover yield, seed nitrogen uptake, total nitrogen uptake, seed uptake efficiency, nitrogen use efficiency and seed yield also increased. However, some accessions performed better under low nitrogen condition. For example, IC267538, IC311819 showed more plant height under zero N-fertilizer application as compared to high N dose. Out of 45 accessions, 36 showed more no. of branches at zero N dose. Accession IC571402 was the best performer under zero N dose as it showed superiority for 8 different traits, viz. no. of branches/plant, test weight, oil content, N% in plants, N% in seed, total N%, grain uptake efficiency and Nitrogen Harvest Index. Similarly, accessions IC424415 and IC571654 performed well for 7 different traits. A set of Brassica juncea germplasm which performed better under low N fertilizer conditions were identified. These nitrogen use efficient accessions would be useful for breeders/researchers to develop varieties of mustard for low nitrogen usages.