Nitrogen Harvest Index in Oats: Its Repeatability and Association with Adaptation1
- H. F. Rattunde and
- K. J. Frey2
The proportion of total plant N that occurs in the grain of cereals is called the nitrogen harvest index (NHI). Twenty oat (Arena sativa L.) cultivars, 10 with high and 10 with low NHI, were used to study the repeatability of NHI measurements over environments and the association of NHI with certain grain and straw yield characteristics, i.e., mean yield, regression response to environments with differing levels of N availability, and stability of that yield response. The NHI values for the oat cultivars were determined at low N (0 kg ha−1) and high N (224 kg−1 in 1979 and 100 kg ha− in 1981). Adaptation to variable soil N was evaluated in 12 environments with varying N availability for 2 yrs. The NHI values were highly consistent across N levels (r=0.72**, significant at the 0.01 probability level) but less so across years (r=0.57**). The NHI values were less consistent across years at low soil N (r=0.18) than at high (r=0.75**). Selection for NHI in the high N environment gave realized heritabilities of 1.01 for high and 0.85 for low NHI lines. The NHI was positively associated with mean grain yield and response of grain yields to environmental productivity, but was inversely related to mean straw yield.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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