Key Laboratory of Crop Physiology and Ecology, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, 100081, China.
The Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Corps, College of Agronomy, Shihezi Univerisy, Shihezi, 832000, China.
Sci Rep. 2020 Sep 21;10(1):15378. doi: 10.1038/s41598-020-72435-3.
Marginal superiority is a common phenomenon in crops, and is caused by the competitiveness of individual plant for resources and crop adaptability to crowded growth conditions. In this study, in order to clarify the response of marginal superiority to maize morphology and plant-density tolerance, field experiments without water and nutrition stress were conducted at Qitai Farm in Xinjiang, China, in 2013-2014 and 2016-2019. The results showed that no more than three border rows of all the cultivars had marginal superiority under high density, about 90% of all the cultivars had no more than two border row that had marginal superiority and a significant negative correlation was observed between marginal superiority and population grain yield (first border row: y = - 2.193x + 213.9, p < 0.05; second border row: y = - 2.076x + 159.2, p < 0.01). Additionally, marginal superiority was found to have a significant positive relationship with plant density (first border row: y = 6.049x + 73.76, p < 0.01; second border row: y = 1.88x + 95.41, p < 0.05) and the average leaf angle above the ear (first border row: y = 2.306x + 103.1, p < 0.01). These results indicated that the smaller the leaf angle above the ear, the weaker the marginal superiority and the higher the grain yield. It suggests that the magnitude of marginal superiority in the border rows can be an indicator for plant-density tolerance under high density. What's more, cultivars with small leaf angle above the ear can be selected to weaken the marginal superiority and improve grain yield under high plant density. Conversely, cultivars with a large leaf angle above the ear can be selected to achieve higher individual yield in intercropping systems with no more than four rows alternated with other crops.
边际优势是作物中常见的现象，是由个体植物对资源的竞争力和作物对拥挤生长条件的适应性引起的。本研究在 2013-2014 年和 2016-2019 年，在中国新疆奇台农场进行了无水分和养分胁迫的田间试验，以阐明边际优势对玉米形态和植物密度耐受性的响应。结果表明，在高密度下，所有品种的边缘行不超过 3 行具有边际优势，约 90%的品种不超过 2 行具有边际优势，且边际优势与群体粒产量呈显著负相关（第一行：y = -2.193x + 213.9，p < 0.05；第二行：y = -2.076x + 159.2，p < 0.01）。此外，发现边际优势与种植密度呈显著正相关（第一行：y = 6.049x + 73.76，p < 0.01；第二行：y = 1.88x + 95.41，p < 0.05）和穗上平均叶角（第一行：y = 2.306x + 103.1，p < 0.01）。这些结果表明，穗上叶角越小，边际优势越弱，粒产量越高。这表明在高密度下，边行的边际优势幅度可以作为植物密度耐受性的指标。此外，选择穗上叶角较小的品种可以减弱边际优势，提高高密度下的粒产量。相反，可以选择穗上叶角较大的品种，以在与其他作物交替种植不超过 4 行的间作系统中实现更高的个体产量。
