Yield–Density Relation of Glyphosate‐Resistant Soya beans and their Responses to Light Enrichment in North‐eastern USA

Abstract

Optimum plant population densities are a key means of achieving higher seed yield in soya bean [Glycine max (L.) Merr.]. Limited information is available on yield-density relation of glyphosate-resistant soya beans in north-eastern USA. The objective of this research was to determine the appropriate populations for glyphosate-resistant soya beans, and if the yield potential of glyphosate-resistant soya bean produced in light-enriched conditions was affected by populations. Eight glyphosate-resistant soya bean cultivars with three populations (300 000, 500 000 and 800 000 plants ha )1 ) were grown under both ambient and light-enriched conditions in 2002 and 2003. Yield of all cultivars responded to density linearly. As density increased, grain yield was increased by up to 92 % among cultivars. Light enrichment increased yield for all cultivars across the 2 years, although some cultivars were more sensitive. Harvest index either remained unchanged or declined slightly at higher density in 2002, and there was no difference among treatments in 2003. Both pod number and seed number per plant were significantly decreased with the increase of density across the 2 years, while seeds per pod declined slightly or remained unchanged. Greater seed size was obtained in higher density with varied degree depending on cultivars across the 2 years except for those cultivars with relatively larger seed. The increase in seed size by light enrichment was cultivar and density dependent, and varied between years. 800 000 plants ha )1 could be a suitable practice in producing higher yield in north-east USA for glyphosate-resistant soya bean. Maintaining the mass of an individual seed is an important strategy in achieving high yield at high population. Establishing mechanisms responsible for the greatest yields via high population under lightenriched conditions, may provide insights for management and phenotypic improvement.

Characterization of 56 Soybean Accessions on Yield Components and Maturity-related Traits

“…The environments, therefore, affect the pod productivity and then affect the seed yield per plant for the soybean accessions tested. Further more, the yield variation is not only influenced by external factors which mostly determined by different environmental conditions but also it also is influenced by internal factors especially the genetic make-up of the soybean accessions (Liu et al, 2006) as clearly demonstrated by this study. …”

Soybean yield and yield component distribution across the main axis in response to light enrichment and shading under different densities

“…That is either to increase pod number per plant or seed number per pod. Liu et al (2006b) suggested that some internal factors rather than external input regulate the seed number per pod in some cultivars. The variation in seed number per pod observed at the extreme node positions was much greater than that at the middle mainstem nodes of soybean plants.…”

“…High populations provide a way to optimize grain yields in shortseason production systems (Liu et al 2006b). The breeding and selection of semi-dwarf cultivars and adoption of narrow row spacing made high densities possible, and thus increased soybean yield (Svecnjak et al 2006).…”

Determinants of soybean [Glycine max (L.) Merrill] production system in Benin

“…Liu et al (2006) and Liu et al, 2008) reported that application of appropriate plant density help reducing the time required for canopy closure, improving crop growth and consequently biomass and grain yield of soybean production systems. Although most of the soils used to cultivate soybean in Benin are degraded, producers in their majority do not use fertilizers to improve soil fertility level and they still claim that soybean does not need fertilizers for growth.…”