Physiological and Phenological Responses of Historical Soybean Cultivar Releases to Earlier Planting

Abstract

The trend toward earlier soybean [Glycine max (L.) Merr.] planting in the midwestern United States has interacted synergistically with genetic yield gain to provide improvement in on‐farm yields. However, the impacts of earlier planting dates and their interaction with genetic gain in physiological and phenological traits remain unclear. The objectives of this study were to determine if a 30‐d difference in planting date affected measured rates of genetic improvement in (i) total dry matter (TDM) production, (ii) harvest index (HI), and (iii) growth‐stage duration in the north‐central United States. Research was conducted at Arlington, WI, Urbana, IL, and Lafayette, IN during 2010 and 2011 using 59 Maturity Group (MG) II cultivars (released 1928–2008) at Wisconsin, and 57 MG III cultivars (released 1923–2007) at Illinois and Indiana, with targeted planting dates of 1 May and 1 June. A mixed‐effect regression analysis was used to model genetic change in TDM, HI, and growth stage duration as impacted by planting date. Breeding efforts have increased TDM(R7), HI, seed‐fill duration (SFD), and reproductive growth duration over time, as vegetative growth duration has been reduced. Early planting provided increased TDM(R7) and longer reproductive growth duration, but had no effect on HI or SFD. A synergistic planting date × year of release interaction existed for TDM(R7) in both maturity groups, but not for HI or SFD, suggesting that the higher yields in newer, early‐planted cultivars resulted from greater TDM production, not improved HI or SFD.

Effect of early sowing on growth and yield of determinate and indeterminate soybean (<I>Glycine max</I> (L.) Merr.) cultivars in a cool region of northern Japan

“…However, the increase of the 100-seed weight was not consistent throughout the experiments. Several researchers reported no effect of sowing date on the 100-seed weight Bastidas et al, 2008;De Bruin and Pedersen, 2008;Rowntree et al, 2014 , which agrees well with the present results.…”

“…These differences of parameters between sowing dates were probably owing to those in root development as discussed later. Thus, early sowing did not increase mean C f , CumIR, CGR and thereby aboveground biomass and seed yield in 2015 Tables 2, 4 . It was reported that the longer growth duration was involved with yield increase Rowntree et al, 2014;Matsuo et al, 2016 . The present study revealed that early sowing extended the periods from VE to R1 and R1 to R7 regardless of the cultivars in the three years Table 2 , but the longer growth duration by early sowing did not always resulted in yield increase.…”

“…Several researchers recently suggested that genetic improvement has contributed to the rapid soybean yield gain in the United States Koester et al, 2014;Rincker et al, 2014;Rowntree et al, 2014;Specht et al, 2014. More recently, Kawasaki et al 2016 reported that American cultivars had better seed yield than Japanese cultivars in a warm region of Japan.…”

Modelling soybean yield responses to seeding date under projected climate change scenarios

“…Ruiz-Vera et al (2013) concluded that under future climate conditions, the combined effects of elevated CO 2 concentration and higher temperature would likely reduce growth due to overriding environmental factors, but this conclusion was based on current crop cultivars. From (Morrison et al 1999;Rowntree et al 2014), and breeding efforts to keep high harvest index will likely continue. Selecting cultivars from the right MG for the warmer future climate should be an essential adaptation measure for soybean production in regions where it is currently cool.…”

Phosphorus and Potassium Uptake, Partitioning, and Removal across a Wide Range of Soybean Seed Yield Levels

“…The work by Hanway and Weber (1971a) in the 1960s has been the base understanding of soybean P and K utilization and requirements for decades. However, superior genetic yield potential (Rincker et al, 2014), extended reproductive growth period (Zeiher et al, 1982), and greater dry matter (DM) harvest index (Koester et al, 2014) of current varieties, in conjunction with better management practices (Rowntree et al, 2014), have increased the frequency of growers achieving yields >5000 kg ha −1 . These factors have likely altered soybean P and K requirements and contributed to declining P and K soil-test levels of some US soybean production regions (Fixen et al, 2010) and possibly limited yield.…”