<b>Inheritance of resistance to <i>Meloidogyne incognita</i> race 3 in cotton accession TX 25

Abstract

Cotton producers worldwide suffer with the losses caused by the presence of phytonematodes. The aim of the present study was to investigate the inheritance of resistance to Meloidogyne incognita race 3 in Gossypium hirsutum variety punctatum accession TX 25. Accessions of Gossypium sp. were obtained from the germplasm bank of Embrapa Cotton. Two experiments were performed in two consecutive years. In the first experiment, a susceptible parental line, FiberMax 966, a resistant parental line, TX 25, and their F 1 , F 2 and backcross generations were tested. In the second experiment, parental lines FiberMax 966 and TX 25, their F 2 generation, and genotypes M315 (resistant), LA887 and DeltaOpal (moderately resistant) were tested. In both experiments, plants were inoculated with 2000 eggs and J2 of M. incognita race 3. The gall index, egg mass index and reproduction factor were evaluated 120 days following inoculation. In the first experiment, plants from the F 1 and backcross generations were susceptible. Plants from the F 2 generation presented a 3:1 resistant-to-susceptible ratio in the two experiments, indicating oligogenic resistance.Herança da resistência do acesso TX 25 de algodoeiro a Meloidogyne incognita raça 3 RESUMO. Os cotonicultores do mundo inteiro sofrem com as perdas causadas pela presença de fitonematoides nas lavouras. Assim o objetivo deste trabalho foi estudar a herança da resistência do acesso TX 25 de Gossypium hirsutum raça punctatum a Meloidogyne incognita raça 3. Foram utilizados acessos de Gossypium sp. pertencentes ao Banco de Germoplasma da Embrapa Algodão. Foram realizados dois experimentos em dois anos consecutivos. No primeiro ano foram testados FiberMax 966 e TX 25 como parentais suscetível e resistente, respectivamente, e as gerações F 1 , F 2 e retrocruzamento. No segundo experimento foram testados os parentais FiberMax 966 e TX 25, a geração F 2 além dos genótipos M315 (resistente) LA887 e DeltaOpal (moderadamente resistentes). Em ambos experimentos as plantas foram inoculadas com 2000 ovos e J2 de M. incognita raça 3. As avaliações ocorreram aos 120 dias após a inoculação, e avaliou-se índice de galhas, índice de massa de ovos e fator de reprodução. No primeiro experimento as plantas da geração F 1 e do retrocruzamento se mostraram suscetíveis, As plantas da geração F 2 nos dois experimentos apresentaram uma proporção de três plantas resistentes para uma suscetível indicando resistência de caráter oligogênico.Palavras-chave: Gossypium hirsutum, nematoide de galhas, segregação gênica.

Identifying cotton genotypes resistant to Meloidogyne incognita race 3 using Blup

“…However, genotype meanbased selection would be efficient. Alves et al (2017) reported that the genetic control of cotton resistance to Meloidogyne incognita race 3 is explained as an oligogenic inheritance. The resistance may suffer a greater influence from the environment, if compared to monogenic inheritance.…”

“…In Brazil, no cotton cultivars showing both resistance to RKN and good agronomic characteristics are available. Therefore, identifying and characterizing sources of resistance that can be incorporated into improved materials are the key to a future sustainable cotton production (Alves et al 2017).…”

Resistance of Several Hibiscus cannabinus genotypes Against Meloidogyne incognita

“…Penggunaan nematisida kimia dapat menyebabkan kerusakan lingkungan dan kesehatan manusia karena toksisitasnya yang tinggi sehingga penggunaannya dibatasi. Penggunaan tanaman tahan terhadap nematoda merupakan cara pengendalian yang efektif untuk menekan kepadatan populasi nematoda dan membatasi ambang kerusakan, sehingga dapat menekan kehilangan hasil tanaman (de Deus Barbosa et al 2009;Davis dan Stetina 2016;Costa et al 2017).…”