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Nitrogen efficiency indexes association with nitrogen recovery, utilization, and use efficiency in spring barley at various nitrogen application rates
Author(s) -
Ali Mohamed Abdelaal,
Ghazy Abdelhalim I.,
Alotaibi Khaled D.,
Ibrahim Omar Maghawry,
AlDoss Abdullah A.
Publication year - 2022
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.1002/agj2.21128
Subject(s) - nitrogen , agronomy , hordeum vulgare , field experiment , chlorophyll , biology , fertilizer , yield (engineering) , grain yield , poaceae , zoology , chemistry , horticulture , materials science , organic chemistry , metallurgy
The nitrogen use efficiency (NUE) is the ratio of the N uptake by the plant to the total amount of applied N fertilizer. The optimization of NUE is essential for sustainable agriculture, especially in the breeding programs to improve the yield of barley ( Hordeum vulgare L.). We investigated the NUE variation in 32 barley genotypes and to examine the response relationship between phenotypic traits and N level to determine the traits essential for the selection of breeding programs to optimize the NUE. The NUE was investigated in 32 barley genotypes for 2 yr under field conditions using three N levels (60, 120, and 180 kg N ha −1 ). Growth, physiological and agronomic traits, and N efficiency‐related parameters were determined. The parameters investigated were significantly affected by N application and its interactions with traits. Plant height, biological yield, spike length, and grain number (GN) were increased at higher N levels, but the 1,000‐grain weight decreased. The lowest grain yield was 2,000.7 kg ha −1 at 60 kg N ha −1 , and the highest was 8,607.9 kg ha −1 at 120 kg N ha −1 . An increase in the N rate from 60 to 120 kg N ha −1 was associated with a higher total chlorophyll content (CHL SPAD ) (from 19.04 to 23.13), but no significant change in CHL was seen at 180 kg N ha −1 . The agronomic nitrogen use efficiency (ANUE), fertilizer N recovery efficiency and the nitrogen utilization efficiency were both reduced with an increase of the N application rate. A path analysis revealed that GN was the most essential trait for NUE breeding program selection due to its high direct effect (0.72) on ANUE. A linear discriminant analysis showed that CHL at 60 d after sowing was the best trait for distinguishing low from high N levels.