Mr. Vilsteren,breeding crops for higher P use efficiency is very important  for efficient utilization of fertilizer P.The two crops selected are very important food crops but probably inefficient utilizers of applied P.If I remember well,  their root systems are shallow and they are not so efficient in P uptake .As these crops need higher inputs of P for higher yield,they may also  leave high  amount of residual P in soil after their harvest.So their root systems need modification/improvement for higher P uptake by breeding techniques.

Hi Sjoerd,

I hope the folowing artcles will be useful for you.

Best regards,

Noemi

Annangi Subba Rao, Thanks for the info. 

 Noemí Colombo, thank you, I will certainly look in to them. 

Dr Jonathan Lynch is doing lot of such kind work...visit his ROOT LAB page http://plantscience.psu.edu/research/labs/roots/publications

You can focus your research on absorb of ions  antagonistic and synergistic properties in soil and also PH of soil. it is better than of root transformation because P is an immobile ion and it stays on topsoil. 

This is the area , perhaps so important , but equally neglected , since breeding work for better NUE comes at the last in the itinerary of breeders, while agronomists and Soil Scientists usually confine their work with regard to agronomic NUE predominantly, leave alone the crops like onion and potato...so to say....

For breeding programs, it would be extremely helpful to identify easily assessable traits that are related to N efficiency. One example of this is that in potato high N efficiency can be highly correlated with late maturity (see Ospina et al., Swain et al., Tiemens-Hulscher et al.). However, many traits contribute to nutrient efficiency but are not easy to identify as they are very much influenced by the interaction with the environmental factors. Chan-Navarrete et al. tried to avoid that environmental influence by testing a set of cultivars on a hydroponics system under controlled greenhouse conditions. For a better understanding of N efficiency ecophysiological models can be very helpful (e.g. Dresbøll and Thorup-Kristensen, Kerbiriou et al.). In the future molecular methods will largely increase the prospects for a directed improvement of N efficiency.

It is possible to identify QTL (Quantitative Trait Loci) for yield and yield components under different N nutrition regimes, for example in oilseed rape (Bouchet et al.) or barley (Kindu et al.). Plant roots play a central role in the acquisition of both nutrients and water from the soil. The plant root system can by characterized by a number of traits with complex interactions like root length, rooting depth, root growth rate, root hair density, root hair length and others. Therefore differences in root characteristics are not always directly related to N efficiency or yield as shown for perennial ryegrass (see Deru et al.). Moreover it is very difficult to measure root traits under realistic conditions. One interesting approach is to use soil columns of two meter length positioned outdoors to simulate root growth in the natural environment as presented by Ytting et al. Source : Euphytica (2014) 199:1–2 .DOI 10.1007/s10681-014-1206-1

PDFs enclosed for further reading ...