Ruisi Paolo, Frangipane Benedetto, Amato Gaetano, Frenda Alfonso S, Plaia Antonella, Giambalvo Dario, Saia Sergio
Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo Palermo, Italy.
Centro di Sperimentazione e Certificazione delle Sementi Battipaglia, Italy.
Front Plant Sci. 2015 Mar 25;6:185. doi: 10.3389/fpls.2015.00185. eCollection 2015.
Choosing genotypes with a high capacity for taking up nitrogen (N) from the soil and the ability to efficiently compete with weeds for this nutrient is essential to increasing the sustainability of cropping systems that are less dependent on auxiliary inputs. This research aimed to verify whether differences exist in N uptake and N fertilizer recovery capacity among wheat genotypes and, if so, whether these differences are related to a different competitive ability against weeds of wheat genotypes. To this end, 12 genotypes, varying widely in morphological traits and year of release, were grown in the presence or absence of interspecific competition (using Avena sativa L. as a surrogate weed). Isotopic tracer (15)N was used to measure the fertilizer N uptake efficiencies of the wheat genotypes and weed. A field experiment, a split-plot design with four replications, was conducted during two consecutive growing seasons in a typical Mediterranean environment. In the absence of interspecific competition, few differences in either total N uptake (range: 98-112 kg N ha(-1)) or the (15)N fertilizer recovery fraction (range: 30.0-36.7%) were observed among the wheat genotypes. The presence of competition, compared to competitor-free conditions, resulted in reductions in grain yield (49%), total N uptake (29%), and an (15)N fertilizer recovery fraction (32%) that were on average markedly higher in modern varieties than in old ones. Both biomass and grain reductions were strongly related to the biomass of the competitor (correlation coefficients > 0.95), which ranged from 135 to 573 g m(-2). Variations in both grain and biomass yield due to interspecific competition were significantly correlated with percentage of soil cover and leaf area at tillering, plant height at heading, and total N uptake, thus highlighting that the ability to take up N from the soil played a certain role in determining the different competitive abilities against weed of the genotypes.
选择具有从土壤中高效吸收氮（N）能力以及与杂草有效竞争这种养分能力的基因型，对于提高减少对辅助投入依赖的种植系统的可持续性至关重要。本研究旨在验证小麦基因型之间在氮吸收和氮肥回收能力上是否存在差异，如果存在差异，这些差异是否与小麦基因型对杂草的不同竞争能力有关。为此，在有或没有种间竞争（使用燕麦作为替代杂草）的情况下种植了12个在形态特征和发布年份上差异很大的基因型。使用同位素示踪剂（15）N来测量小麦基因型和杂草对肥料氮的吸收效率。在典型的地中海环境中，连续两个生长季节进行了一项田间试验，采用四重复的裂区设计。在没有种间竞争的情况下，在小麦基因型中未观察到总氮吸收量（范围：98 - 112 kg N ha(-1)）或（15）N肥料回收比例（范围：30.0 - 36.7%）有太大差异。与无竞争条件相比，竞争的存在导致现代品种的籽粒产量（49%）、总氮吸收量（29%）和（15）N肥料回收比例（32%）的降低平均明显高于老品种。生物量和籽粒的减少都与竞争者的生物量密切相关（相关系数>0.95），竞争者生物量范围为135至573 g m(-2)。种间竞争导致的籽粒和生物量产量变化与分蘖期的土壤覆盖百分比、叶面积、抽穗期株高和总氮吸收量显著相关，从而突出表明从土壤中吸收氮的能力在决定基因型对杂草的不同竞争能力方面起到了一定作用。
