TABLE 2.

The trait category and number of QTL compiled per category in the QTL meta-analysis for the nitrogen use efficiency and related traits in rice.

Trait category	Number of QTL
Agricultural nitrogen-absorption efficiency	65
Nitrogen content	118
Nitrogen use efficiency	73
Nitrogen-related enzymes and amino acids (proline, peroxidases, nitrate reductase, free amino acid, soluble proteins, catalase, NADH-glutamate synthetase)	53
Photosynthetic rate and chlorophyll content	60
Plant height	105
Shoot dry weight	57
Total dry biomass	89
Leaf number and area	20
Root traits (root length, root number, root thickness, root dry weight)	53
Grain yield and related traits (harvest index, biomass yield, number of grains per panicle, panicle length, panicle number per plant, grain weight, days to 50% flowering, number of productive tillers, spikelet fertility, partial factor productivity)	637
Total	1,330