The Frustration with Utilization: Why Have Improvements in Internal Phosphorus Utilization Efficiency in Crops Remained so Elusive?

Abstract

Despite the attention internal phosphorus utilization efficiency (PUE) of crops has received in the literature, little progress in breeding crop cultivars with high PUE has been made. Surprisingly few studies have specifically investigated PUE; instead, genotypic variation for PUE has been investigated in studies that concurrently assess phosphorus acquisition efficiency (PAE). We hypothesized that genotypic differences in PAE confound PUE rankings because genotypes with higher PAE suffer a lower degree of P stress, resulting in lower PUE. The hypothesis was tested by comparing soil-based screening to a modified technique whereby rice genotypes were grown in individual containers with a single dose of solution P, to eliminate differences in P uptake among genotypes. Genotypic differences in PUE were apparent in root and shoot tissue using the modified nutrient solution technique, but PUE rankings showed no correlation with those from traditional soil-based screening. We conclude that PUE in soil-based screening systems is unavoidably linked with genotypic PAE, resulting in PUE rankings confounded by differences in P uptake. Only screening techniques assuring equal P uptake are suitable for the exploitation of genotypic variation for PUE.

Identifying markers associated with yield traits in Nagina22 rice mutants grown in low phosphorus field or in alternate wet/dry conditions

“…On the other hand, abundant use of P fertilizers derived from livestock manures, a common practice in intensive agriculture, affects environment in the form of eutrophication of freshwater habitats (Tiessen, 2008;Ashley et al, 2011). One approach suggested to tackle this problem of low or excess use of P in farming is the identification and development of genotypes with high phosphorous use efficiency (PUE) in low P soils without compromising yield (Aluwihare et al, 2016;Rose et al, 2010Rose et al, , 2011Rose et al, , 2012Rose et al, , 2015. More than PUE, it is the ability to tolerate P deficiency to different extent and yet give high yield which is more important.…”

Genetic approaches to enhancing phosphorus-use efficiency (PUE) in crops: challenges and directions

“…Further, studies have shown that P acquisition and utilisation are negatively correlated (Wissuwa et al 1998;Su et al 2009), with those authors suggesting that improvement of a genotype for both P acquisition and utilisation will be difficult to achieve. Rose et al (2011) provide further evidence for this phenomenon in rice, concluding that P acquisition and P utilisation are unavoidably linked in traditional soil-and field-based screening. Using a hydroponic-based method, Rose et al (2011) reported that the linkage between P acquisition efficiency and P utilisation can be broken.…”

“…Rose et al (2011) provide further evidence for this phenomenon in rice, concluding that P acquisition and P utilisation are unavoidably linked in traditional soil-and field-based screening. Using a hydroponic-based method, Rose et al (2011) reported that the linkage between P acquisition efficiency and P utilisation can be broken. It remains to be seen if this new approach will be of practical use given the reported poor relationship between hydroponic P experiments and pot-and field-based assays (Hayes et al 2004).…”

Prospects for Genetic Improvement in Internal Nitrogen Use Efficiency in Rice

“…We suggest attempts to improve NUE agron in rice by exploiting genetic variation should focus on identifying variation for biomass production per unit of plant N uptake during vegetative growth stages (NUE veg ) because this ultimately contributes to NUE agron (grain yield per unit of N uptake) and is independent of the HI. We previously developed methods to screen for phosphorus use efficiency at the vegetative stage [25,26], and these methods enabled the successful mapping of loci associated with enhanced phosphorus use efficiency at the vegetative stage [27]. We propose that similar screening techniques could be developed to enable mapping of loci associated with enhanced NUE veg in rice.…”