Manganese Response in Conventional and Glyphosate Resistant Soybean

Abstract

Fertilizer Management 606A gronomy J our n al • Volu me 102 , I s sue 2 • 2 010 ABSTRACT Glyphosate-resistant (GR) soybean [Glycine max (L.) Merr.] is widely produced and provides many benefi ts to production agriculture, however, recent reports suggest that GR soybean genetics may result in reduced Mn uptake and increased response to Mn fertilization. Th e objective of this research was to determine response of GR and conventional (CV) soybean near-isolines to Mn fertilization. Th e soybean near-isoline pair KS4202 and K4202RR was planted at three locations and near-isoline pair KS4602N and KS4602NRR was planted at two locations in a split-block fi eld study. Manganese treatments consisted of soil-applied MnSO 4 at 0, 2.8, 5.6, and 8.4 kg Mn ha -1 and foliar applied Mn-glucoheptonate at 0.22 and 0.45 kg Mn ha -1 . Leaf tissue was analyzed for Mn at R1, R3, and R6 growth stages and seed was analyzed for Mn at harvest. Manganese concentrations in leaf tissue were above the critical value and were not aff ected by GR genetics at any location or growth stage. However, there were yield responses to Mn applications at three of the fi ve locations. KS4202RR soybean yield increased by 800 and 275 kg ha -1 with increasing Mn application rate at two locations when the near-isoline KS4202 yield did not increase. In contrast, at the third responsive location KS4602NRR did not respond to Mn application when the near-isoline KS4602N yield increased by 450 kg ha -1 . Th ese results indicate that although soybean response to Mn is infl uenced by genetics, neither the Mn uptake nor the Mn responsiveness were conclusively aff ected by glyphosate-resistance in soybean.

Efeitos de doses e épocas de aplicação de manganês via foliar no cultivo de soja convencional e em derivada transgênica RR

“…Corroborando assim com Lavres Júnior et al (2008) De modo geral, com aplicação realizada em R 1 ou em R 3 , quando as cultivares foram distintas, os materiais convencionais foram mais produtivos em relação aos seus derivados transgênicos RR, tanto na ausência quanto na aplicação do Mn foliar (Tabela 4). Corroborando com os resultados obtidos por Loecker et al (2010), que constataram que a transgenia RR não proporcionou conclusivamente em maior resposta à aplicação de Mn.…”

“…Existem algumas explicações teóricas que podem sustentar estas alegações, que geralmente estão na direção de dois mecanismos gerais: (i) interação direta ou indireta entre glifosato e Mn, ou, (ii) diminuição na absorção e translocação de Mn resultante da alteração genética (LOECKER et al, 2010).…”

A Meta-Analysis for the Impact of Transgenic Crop Adoption on Corn and Soybean Yield

“…In the early adoption stage of TCs, transgenic crops with IR traits usually yielded similar to near-isolines (Baute et al, 2002;Cox and Cherney, 2001;Dillehay et al, 2004;Traore et al, 2000), suggesting that the insertion of an IR gene in the early IR crops did not provide higher yield. However, some of the first transgenic crops with GR traits provide the same or even lower yield on average than conventional varieties due to the introduction of the GR gene into varieties with lower yield potential (Elmore et al, 2001;Heatherly et al, 2002 andLoecker et al, 2010;Shaw et al, 2001). However, transgenic traits were later introduced into improved potential yield varieties and generally showed that transgenic hybrids produced similar or higher yields than conventional varieties.…”

Biotechnology: Herbicide-Resistant Crops

“…Most of these studies were conducted in greenhouse and have been used as support for claims of decreased yields and other adverse effects of glyphosate on GR crops (e.g., Huber, 2007;Johal and Huber, 2009). Other research groups have found no effects of glyphosate on mineral nutrition in GR crops (e.g., Bailey et al, 2002;de Andrade and Rosolem, 2011;Duke et al, 2012a;Henry et al, 2011;Loecker et al, 2010;Rosolem et al, 2010;Serra et al, 2011). A thorough analysis of this topic was made by Duke et al (2012b).…”