Herança da tolerância à toxicidade de alumínio em trigo duro

Abstract

ResumoO trigo duro (Triticum durum Desf.), também conhecido como "trigo para macarrão", caracteriza-se pela farinha amarelada (sêmola) adequada para o preparo de massas. No Brasil ainda não ocorre seu cultivo extensivo em decorrência, principalmente, de problemas com sua adaptação aos solos ácidos, com níveis tóxicos de alumínio. Visando estimar a herança da tolerân-cia à toxicidade de alumínio efetuaram-se cruzamentos entre o genótipo de trigo duro tolerante, P33 e o sensível, IAC-1003 para a obtenção do híbrido em geração F 1 e a seguir das gerações F 2 , F 3 , RC 1 F 1 , RC 2 F 1 , RC 1 F 2 e RC 2 F 2 . Todos os genótipos foram testados em soluções nutritivas e a tolerância à toxicidade de alumínio foi medida pela capacidade de crescimento da raiz primária central em solução nutritiva completa, após tratamento de 48 horas em solução contendo 2 mg L -1 de Al 3+ . O genótipo P33 diferiu do IAC-1003 por um par de alelos dominantes para a tolerância à presença dessa concentração de alumínio nas soluções nutritivas e pode ser usado como fonte de tolerância ao alumínio em programas de melhoramento de trigo duro.Palavras-chave: Triticum durum Desf., genes dominantes, solos ácidos, melhoramento genético. Inheritance of aluminum toxicity in durum wheatAbstract Durum wheat (Triticum durum Desf.), also known as "pasta wheat", is characterized to produce yellow flour (semolina) adequate for pasta elaboration. In Brazil, its extensive cultivation is limited by the low crop adaptability to acid soils, with toxic aluminum levels. Aiming to estimate the inheritance of the aluminum toxicity tolerance, crosses were made between tolerant durum wheat genotype P33 and the sensitive IAC-1003 to obtain the hybrid in F 1 generation and subsequent generations F 2 , F 3 , BC 1 F 1 , BC 2 F 1 , BC 1 F 2 and BC 2 F 2 . All genotypes were tested in nutrient solutions and the aluminum toxicity tolerance was measured by the growth capacity of the primary central root after 48 hours of treatment with 2 mg L -1 of aluminum in nutrient solution. The genotype P33 has differed from IAC-1003 by one pair of dominant alleles for the tolerance at the presence of this aluminum concentration in the nutrient solution and it could be used as source of aluminum tolerance in durum wheat breeding programs.

Aluminum accumulation in the wheat production chain: a review

“…This same behavior was observed when comparing two wheat cultivars, resulting in a stimulus for root hair growth in the most tolerant cultivar, which reinforces the presence of physiological mechanisms in response to aluminum toxicity (Garcia-Oliveira et al, 2016). Plant's tolerance to Al 3+ in acidic soil is related to genetic factors (Del Guercio & Camargo, 2011;Han et al, 2016). Different tolerances may be found between cultivars of the same species, which is observed, e.g., in some studies on wheat (Camargo et al, 2006;Del Guercio & Camargo, 2011;Delhaize et al, 2012;Garcia-Oliveira et al, 2016;Liu et al, 2018;Silva et al, 2010;Zhou et al, 2007) and oats (Crestani et al, 2011;Silveira et al, 2013).…”

“…Each aluminum species has a characteristic potential for toxicity to the plant, and the Al 3+ ion has been identified as toxic to most plants (Salet, 1998). This effect was observed in specific studies on wheat (Del Guercio & Camargo, 2011;Delhaize et al, 2012;Iqbal, 2014;Li et al, 2022;Silva et al, 2010), and also in sorghoum growth (Miller et al, 2009).…”

“…The effect of aluminum toxicity on plants interferes with root growth and may occur from multiple mechanisms (Del Guercio & Camargo, 2011;Li et al, 2022;Liu et al, 2018;Silva et al, 2010;Szabó et al, 2015;Zhou et al, 2007).…”

“…In roots, the effect of aluminum toxicity is identified when their growth is inhibited (Del Guercio & Camargo, 2011;Liu et al, 2018;Silva et al, 2010;Szabó et al, 2015;Zhou et al, 2007), also followed by an increase in the content of aluminum and phosphorus, which may be a response of the plant's defense mechanism (Szabó et al, 2015). However, Al 3+ detoxification by phosphorus occurs mainly in the soil and not in the plant tissue (Iqbal, 2014).…”

Cytomolecular characterization of cultivars and landraces of wheat tolerant and sensitive to aluminum toxicity

“…Acidic soils are common in different regions of Brazil, mainly in the North and Midwest, followed by the Southeast and South regions (Fageria and Stone 1999). Wheat cultivation is prevalent in the South, Southeast and Midwest Brazil, and several studies have been carried out in the last decades in order to enable large-scale cultivation of durum wheat in Southeast Brazil, particularly in the State of São Paulo (Camargo et al 1992;Camargo et al 1999;Camargo et al 2006;Del Guercio and Camargo 2011). However, besides the lack of tolerance to aluminum toxicity, durum wheat in Brazil also has no grain dormancy, exhibits low productivity and is largely susceptible to diseases such as wheat leaf rust (Puccinia triticina = P. recondite f. sp.…”