Genetic variability for root traits and its role in adaptation under conservation agriculture in spring wheat

Abstract

Breeding wheat for improved root traits and suitability under conservation agriculture (CA) practices has the potential to boost and sustain grain yield in different parts of the world. Difficulties in scoring for root phenes under field conditions, considered a major hurdle to breed for root traits, can be surmounted by scoring under hydroponic conditions. Significant variability was found for rooting depth (RD), shoot dry weight (SDW) and root dry weight (RDW) when 175 genotypes were screened for root traits under hydroponic conditions. Further evaluation of a subset of 19 genotypes under field conditions showed that four root traits - total root length (TRL), root volume (RV), root surface area (RSA) and root tip numbers (RN) are integrated with RDW because of their positive correlation with this trait. Both RDW and SDW could be combined favorably to obtain the most appropriate (higher) biomass and greater yield under a set of crop growth durations. Significant correlation and strong direct effect of RDW on crop yield under CA appeared to justify its selection in the breeding programme. A derivative of the cross EGPSN-36/ PBW343 showed maximum value for all root traits including RDW and therefore can be used in future breeding programmes.