Abstract
Nitrogen (N) availability is a major factor limiting crop growth and development. Identification of quantitative trait loci (QTL) for N uptake (NUP) and N use efficiency (NUE) can provide useful information regarding the genetic basis of these traits and their associated effects on yield production. In this study, a set of high throughput genotyped chromosome segment substitution lines (CSSLs) derived from a cross between recipient 9311 and donor Nipponbare were used to identify QTL for rice NUP and NUE. Using high throughput sequencing, each CSSL were genotyped and an ultra-high-quality physical map was constructed. A total of 13 QTL, seven for NUP and six for NUE, were identified in plants under hydroponic culture with all nutrients supplied in sufficient quantities. The proportion of phenotypic variation explained by these QTL for NUP and NUE ranged from 3.16–13.99% and 3.76–12.34%, respectively. We also identified several QTL for biomass yield (BY) and grain yield (GY), which were responsible for 3.21–45.54% and 6.28–7.31%, respectively, of observed phenotypic variation. GY were significantly positively correlated with NUP and NUE, with NUP more closely correlated than NUE. Our results contribute information to NUP and NUE improvement in rice.
Highlights
The world’s population will reach 9 billion by 2050 (Gregory and George, 2011)
Our study was designed to precisely characterize more quantitative trait loci (QTL) for rice N uptake (NUP) and N use efficiency (NUE) under hydroponic conditions using a population of chromosome segment substitution lines (CSSLs). These results provide useful information for further dissection of the genetic basis of NUE and NUP, and should facilitate development of rice varieties with better nitrogen uptake and nitrogen use efficiency
The NUP of 9311 was 1.60-fold higher than that of Nipponbare, whereas the NUE was similar (28.60 ± 1.00 g g−1 vs. 27.74 ± 0.95 g g−1). 9311 is a high-yield indica variety developed in the 1990s, and Nipponbare is a low-yield japonica variety developed in the 1950s
Summary
The world’s population will reach 9 billion by 2050 (Gregory and George, 2011). Food shortages are becoming a serious global problem. To guarantee global food security for future generations in view of this population explosion, the estimated annual increase in agricultural productivity needs to be raised to 3% from the current 2% (von Braun, 2010). Nitrogen (N), an essential element for crop growth, is considered to be the main factor limiting crop productivity, second only to water deficiency. Crop production is highly dependent on supply of exogenous N fertilizer (Kraiser et al, 2011). To satisfy the food requirements of an increasing population, the amount of synthetic N applied to crops has risen dramatically, from 12 to 104
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