Variation in root system architecture in cultivated wheat and their progenitors under nitrogen stress

Diploid progenitors of cultivated (hexaploid and tetraploid) wheat are of considerable interest in wheat breeding as these have outstanding potential for resistance to both biotic and abiotic stresses. Root system architecture is a prime feature of crop performance to adapt under soil environmental conditions like nutrient and water stress. Diploid progenitors along with their cultivated wheat have never been assayed for their root parameters in response to the different conditions of nitrogen, the most important nutrient. In present study, we compared cultivated wheat genotypes (two durum and two bread) with 6 accessions of their progenitors viz. Aegilops and Triticum genus under optimum and stressed nitrogen conditions for their root system architecture at seedling stage. Significant variation was noticed between and within the species in most of the Root system architecture parameters. Of all accessions studied, Root system architecture of A. speltoides (BB) accessions AN84 and AN3570 were least affected, whereas the cultivated wheat genotypes were most affected under low nitrogen stress. Hexaploid wheat genotypes HD-2967 and GW-322 showed much pronounced total root size with reduced lateral root size under low nitrogen stress condition. Lateral root size and lateral root density got decreased in all genome species under low nitrogen stress. Usually, all genotypes showed more number of second order lateral roots at both conditions compared to first order lateral roots. Our study discloses the RSA diversity among diploid progenitors and cultivated wheat in response to low nitrogen stress. This study also suggests that there is significant hidden potential exists for the use of wheat progenitors to improve the root traits for better nitrogen use efficiency.