Early vigorous growth is a major factor influencing nitrogen uptake in wheat

Abstract

A field trial, a lysimeter system study and a nutrient solution experiment were conducted to determine the genotypic differences in nitrogen (N) uptake among wheat (Triticum aestivum L.) genotypes differing in vigour of early growth. Plant growth and N uptake of Vigour 18, a breeding line with early vigour, and the commercial cultivars Westonia, Tincurrin, Camm and Janz were compared. Shoot biomass of Vigour 18 was higher than that of the other genotypes, except for Westonia at booting when 50 kg N ha -1 was applied 3 d after wheat emergence. Vigour 18 had significantly higher efficiency of fertiliser-N uptake than the other four cultivars at tillering when 50 kg N ha -1 was applied. Fertiliser-N uptake efficiency at booting was similar in Vigour 18 and Westonia, but significantly higher than in three other commercial cultivars. Vigour 18 had higher root dry matter, root-length density and root surface area than Janz when examined in columns of soil. The greater root growth of Vigour 18 occurred across all soil layers to a depth of 0.6 m. Differences in total N uptake between Vigour 18 and Janz were apparent from tillering (Z14,22) to booting (Z19,24,49). Vigour 18 also had significantly higher shoot biomass and N uptake than Janz when grown in nutrient culture. Nitrate reductase activity (NRA) expressed on a whole-plant basis was higher for Vigour 18 than for Janz, and was related to total N uptake. However, NRA expressed on a perunit-fresh-weight basis was not significantly different across the cultivars tested. It is concluded that vigorous early root and shoot growth in Vigour 18 was the main driving force for higher N uptake.

Genotypic variation in soil water use and root distribution and their implications for drought tolerance in chickpea

“…Recent studies on the importance of size of roots to grain yields and the timing of soil water utilisation for maximising grain yields under terminal DS had drawn variable conclusions such as positive (Sponchiado et al 1989;White and Castillo 1992;Eghball and Maranville 1993;Kramer and Boyer 1995;Lynch 1995Lynch , 2013Pandey et al 2000aPandey et al , 2000bLiao et al 2004;Nord and Lynch 2009;Puangbut et al 2009;Lopes and Reynolds 2010;Manschadi et al 2010;Zhu et al 2010;Franco et al 2011;Kell 2011;Trachsel et al 2011;Suji et al 2012;Wasson et al 2012Wasson et al , 2014Comas et al 2013;Jaramillo et al 2013;Uga et al 2013; Root traits contribution to drought tolerance Functional Plant Biology Fenta et al 2014;Chimungu et al 2014aChimungu et al , 2014bLynch et al 2014;Bishopp and Lynch 2015) and negative or null (Ritchie 1981;Dardanelli et al 2004;CIAT 2007CIAT , 2008Beebe et al 2009;Itoh et al 2009;Ma et al 2010;Manavalan et al 2011;Ratnakumar et al 2009;Zaman-Allah et al 2011;Kumar et al 2012;…”

Evaluation of Australian wheat genotypes for response to variable nitrogen application

“…In the region used for this study, crops are sown after autumn rainfall when good soil moisture is available for crop establishment and early vegetative growth. Varieties able to take up N during early growth but which restrict tillering and vegetative growth are less susceptible to the late season drought but need to efficiently remobilise the N during grain filling (Liao et al 2004). The main aim of this study was to assess the genetic variation for N response and stability in spring wheat germplasm to determine the scope for improvement of NUE under water-limited, low yielding conditions.…”

Genetic Opportunities to Improve Cereal Root Systems for Dryland Agriculture

“…The tiller inhibitor gene mentioned earlier increases root branching (Duggan et al, 2005;Richards et al, 2007). Some breeding lines originating from crosses between high and low vigour wheat genotypes also show very substantial increases in root branching compared with commercial wheat varieties (Liao et al, 2004, Table 1). …”

“…There is some evidence that aboveground vigour may be related to root system vigour (Table 1). A breeding line, Vig 18, developed by combining traits contributing to early aboveground vigour (Richards and Lukacs, 2002) has been shown to have greater root vigour in direct drilled soils (Watt et al, 2003) and in root boxes (Liao et al, 2004) when compared with the widely grown commercial wheat Janz. Table 1 show a substantial increase in total biomass of Vig 18 over Janz when grown in an outdoor lysimeter system.…”