Morphological description of a novel synthetic allotetraploid(A1A1G3G3) of Gossypium herbaceum L.and G.nelsonii Fryx. suitable for disease-resistant breeding applications.

Rulin Zhan,Paulo Eduardo Teodoro,Yu Ge,Xiaomin Yin,Di Chen,Yingdui He,Lixia Wang,Shun Song

doi:10.1371/journal.pone.0242620

Rulin Zhan, Paulo Eduardo Teodoro + Show 6 more

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https://doi.org/10.1371/journal.pone.0242620

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Abstract

Wild species of Gossypium ssp. are an important source of traits for improving commercial cotton cultivars. Previous reports show that Gossypium herbaceum L. and Gossypium nelsonii Fryx. have better disease resistance characteristics than commercial cotton varieties. However, chromosome ploidy and biological isolation make it difficult to hybridize diploid species with the tetraploid Gossypium hirsutum L. We developed a new allotetraploid cotton genotype (A1A1G3G3) using a process of distant hybridization within wild cotton species to create new germplasms. First of all, G. herbaceum and G. nelsonii were used for interspecific hybridization to obtain F1 generation. Afterwards, apical meristems of the F1 diploid cotton plants were treated with colchicine to induce chromosome doubling. The new interspecific F1 hybrid and S1 cotton plants originated from chromosome duplication, were tested via morphological and molecular markers and confirmed their tetraploidy through flowrometric and cytological identification. The S1 tetraploid cotton plants was crossed with a TM-1 line and fertile hybrid offspring were obtained. These S2 offsprings were tested for resistance to Verticillium wilt and demonstrated adequate tolerance to this fungi. The results shows that the new S1 cotton line could be used as parental material for hybridization with G. hirsutum to produce pathogen-resistant cotton hybrids. This new S1 allotetraploid genotype will contributes to the enrichment of Gossypium germplasm resources and is expected to be valuable in polyploidy evolutionary studies.

Highlights

The Gossypium genus includes 54 species, of which 50 are wild cotton species and four are cultivated cotton species made up of two diploids and two tetraploids [1, 2]
The diploid G. herbaceum cotton species that has been cultivated in China is known as Hongxingcaomian (2n = 2x = 26, A1A1), and is a line that has not been subjected to Morphological description of a novel synthetic allotetraploid (A1A1G3G3) suitable for breeding applications inbreeding
The lines mentioned above were obtained from the China National Wild Cotton Nursery in Sanya, China

Summary

Introduction

The Gossypium genus includes 54 species, of which 50 are wild cotton species and four are cultivated cotton species made up of two diploids and two tetraploids [1, 2]. 90% of commercially produced cotton is cultivated from G. hirsutum L. As the high-yielding quality of cultivated species continuously increases, abiotic and biotic resistance usually does not increase and can even be weakened [3, 4]. To increase the resistance in G. hirsutum. Morphological description of a novel synthetic allotetraploid (A1A1G3G3) suitable for breeding applications

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