Journal of Food, Agriculture and Environment

Dry matter distribution as affected by N rates and intra- and interspecific competition in wheat (Triticum aestivum L.)

Author(s):

Amir Aynehband ^*, Sara Asadi, Afrasiab Rahnama

Recieved Date: 2011-07-16, Accepted Date: 2011-10-17

Abstract:

Wheat (Triticum aestivum L.) is being increasingly grown in Middle East region, but there is a lack of information about some ecological processes limiting accumulation and partitioning of stem dry matter. The influence of intra- and interspecific competition, accumulation and remobilization of dry matter in stem segments was investigated in the bread wheat on the experimental farm of Faculty of Shahid Chamran University of Ahvaz, Iran, during 2010-2011 growing seasons at four nitrogen rates: 0, 50, 100 and 150 kg ha^-1. Experimental design was split-factorial, N rates as main plots and both intraspecific competition (wheat densities) and interspecific competition (present or absent of weed) as sub-plots. Different stem and internode weight and length, their effects and relationships among stem segments and dry matter accumulation and mobilization were measured at 10-d intervals in wheat grown under different N rates. Our results showed that the main effect of nitrogen, intra- and interspecific competition and their interactions were significant. Internode length and weight increased with N application. Mobilized dry matter content was higher in high N application than in no N application for peduncle (136 vs. 102 mg), penultimate (175 vs. 157 mg) and the lower internodes (405 vs. 344 mg). High N application increased mobilization efficiency, expressed as percentage of maximum dry matter mobilized, just in the peduncle by 12.8%, but not significantly changed in penultimate and the lower internodes. Therefore, peduncle, penultimate and the lower internodes had not similar dry matter mobilization efficiency and the mobilization efficiency was lower in peduncle than in other stem internodes. Also, between different N rates, D₂W₁ (highest intra- and interspecific competition) had the greatest mobilization efficiency for peduncle and penultimate, respectively. In general, D₁W₀ (i.e. intraspecific competition) showed relatively the greatest rate and extent of dry matter accumulation and subsequent mobilization in main stem. Moreover, D₂W₀, D₁W₀ and D₂W₁ showed greatest rate and extent of dry matter accumulation in main stem, respectively. In fact, treatments (type of competition) with greater rates of dry matter accumulation and mobilization are exposed less to depressing effect of nitrogen deficiency than those with lower rates. Dry matter mobilized from all three segments of main stem in both intra- and interspecific competition examined in this trial decreased in response to no application of N.

Keywords:

Wheat, dry matter, nitrogen, intraspecific competition, interspecific competition

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Journal: Journal of Food, Agriculture and Environment
Year: 2011
Volume: 9
Issue: 3&4
Category: Agriculture
Pages: 354-363

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