Nitrogen Harvest Index in Oats: Its Repeatability and Association with Adaptation¹

Abstract

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.

Yield and Nitrogen Use Efficiency of Locally Improved Rice Varieties in Rice Based Tidal Flooded Ecosystem of Bangladesh

“…Lalmota was efficient in both locations. Rattunde and Frey (1986) reported that the N harvest index was positively associated with grain yield of oats and response of grain yield. Similarly, Kairudin and Erey (1988) also reported that N harvest index of oats was positively correlated with grain yield and gross protein yield in low and high N. …”

Adubação nitrogenada no perfilhamento da aveia-preta em duas condições de fertilidade do solo

“…Em aveia-preta, as pesquisas com adubação nitrogenada, relacionando doses ou momentos de aplicação e a produção ou qualidade das sementes, são em pequeno número até o momento (Nakagawa et al, 1994(Nakagawa et al, , 1995(Nakagawa et al, , 1996, situação esta contrária à verificada em Avena sativa L. (Frey, 1959;Ohm, 1976;Brinkman & Rho, 1984;Rattunde & Frey, 1986;Marshall et al, 1987;Humphreys et al, 1994). Nakagawa et al (1994Nakagawa et al ( , 1995, estudando em aveiapreta doses e épocas de aplicação de N (na semeadura, no perfilhamento da planta e na emergência da panícula), verificaram a importância do fornecimento do elemento no perfilhamento, para a produção (Nakagawa et al, 1994(Nakagawa et al, , 1995 e a qualidade fisiológi-ca das sementes (Nakagawa et al, 1995), com destaque ao tratamento que recebeu 20 kg/ha na semeadura e 20 kg/ha no perfilhamento.…”

Associations between nitrogen harvest index and yield characteristics of oats

“…One physiological trait related to adaptability of oats (Fawcett & Frey, 1982 ;Rattunde & Frey, 1986) is nitrogen (N) partitioning between grain and straw .…”

“…Fawcett & Frey (1982) suggested that low-NHI oat lines were specifically adapted to low-N environments and high-NHI lines were specifically adapted to high-N environments . Rattunde & Frey (1986) tested this hypothesis with 20 oat lines grown in 12 environments that had different N availabilities and found that high-NHI lines had grain yields that were higher, more responsive, and more stable than did low-NHI genotypes . They concluded that high-NHI lines had general adaptation to diverse N environments .…”

“…The studies by Fawcett & Frey (1982) and Rattunde & Frey (1986) suggest that NHI might be used as a marker trait to indirectly select cereal genotypes adapted to specific N environments ;…”