Poor post-silking kernel development limits summer maize yield in the North China Plain

Abstract

ABSTRACT:Winter wheat (Triticum aestivum)/summer maize (Zea mays) rotation is a major system in the North China Plain. The wheat yield target was achieved recently, whereas the maize yield has been static since the 2000s, even with high density planting and fertilizer input. This study analyses the factors limiting maize growth and yield. Maize yields from eight field trials (2006)(2007)(2008)(2009)(2010)(2011) were classified into five levels: low yield (< 8.25), farmer yield (8.25-9.75), experimental yield (9.75-11.25), record high yield (11.25-12.75), and target yield (> 12.75) t/ha. Shoot dry weight, nitrogen accumulation, and leaf area index at critical stages, yield, and yield components were measured. Grain yield fluctuated from 6.4-13.8 t/ha (10.1 t/ha on average). Insufficient kernel number per ear and low kernel weight limited further yield improvement. Shoot dry weight, leaf area index, and shoot N-accumulation before silking did not vary among the different yield levels, whereas after silking these parameters were significant larger at high yield levels. It can be concluded that low kernel number per ear across yield levels was related to source limitation pre-silking. Additionally, low kernel weight was due to poor post-silking dry matter production. However, the potential of yield increment through increasing source size was limited under the current system. Strategies to enhance post-silking leaf and root function shall therefore be considered to improve post-silking dry matter production and transportation under a high density and high nitrogen input system.

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“…Because maize has a good balance of the source/sink relationship when grown in spring and under no limitation of water supply (Borrás et al 2003;Borras et al 2004;Bonelli et al 2016), probably the stay-green trait would be more adequate for environments or management practices that lead to terminal stress (during kernel filling), which is also more likely to occur under the new scenarios of climate change. This would be the case for summer sowings in rainfed maize, which have become a frequent practice to avoid abiotic stress during flowering in stress-prone areas (Cerrudo et al 2013;Caviglia et al 2014;Tao et al 2015;Giménez et al 2015). However, this management practice positions the grain filling under environments with poor solar radiation and low temperatures, which can make the crop more source-limited (Tao et al 2015;Bonelli et al 2016).…”

“…This would be the case for summer sowings in rainfed maize, which have become a frequent practice to avoid abiotic stress during flowering in stress-prone areas (Cerrudo et al 2013;Caviglia et al 2014;Tao et al 2015;Giménez et al 2015). However, this management practice positions the grain filling under environments with poor solar radiation and low temperatures, which can make the crop more source-limited (Tao et al 2015;Bonelli et al 2016). Thus, a better knowledge of the genetic basis controlling kernel filling, senescence, and C and N remobilization can contribute to improving the potential yield or to lowering its temporal variation (Thomas and Ougham 2014).…”