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Cultivar Differences in Nitrogen Remobilization during Grain Fill in Soft Red Winter Wheat 1
Author(s) -
Van Sanford D. A.,
MacKown C. T.
Publication year - 1987
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1987.0011183x002700020035x
Subject(s) - cultivar , peduncle (anatomy) , biology , anthesis , loam , agronomy , poaceae , field experiment , fructification , winter wheat , horticulture , soil water , ecology
Remobilization of vegetative N during grain fill in wheat ( Triticum aestivum L.) contributes significantly to final grain N content. To assess cnltivar variation for this trait in soft red winter (SRW) wheat, nine cultivars were evaluated in the field for 2 yr at one location on a Maury silt loam soil (fine, mixed, mesic, Typic Paleudalf). Plants were harvested at anthesis and maturity, and divided into spike, peduncle, flag leaf blade; and lower culm plus leaves. Significant cultivar differences in N remobilization from the tlag leaf blade, peduncle, and lower culm were detected. The proportion of N accumulated by the spike derived from vegetative N remobilization ranged among cuitivars from 51 to 91%. Approximately 83% of the total aboveground N at maturity was present in the plant at anthesis, in agreement with other studies. An analysis of cultivar differences indicated that all of the cultivar variation in final spike N could be associated with variation in total N uptake. Cuitivar differences in partitioning of vegetative N measured at anthesis did not contribute significantly to cultivar differences in final spike N. Postanthesis N uptake was associated with lower N utilization efficiency (spike weight/total plant N), higher grain N concentration, and lower grain yields. A controlled study with nutrient solutions subjected six wheat cuitivars to N deprivation at anthesis. The impact of N deprivation on grain N concentration varied among cultivars. The ratio of spike N to total N in all cultivars was increased by N deprivation from 0.69 in the presence of N to 0.82 in the absence of N. For the three cultivars common to both studies, field performance did not agree well with performance under controlled conditions.