Development and characterization of synthetic allotetraploids between diploid species Gossypium herbaceum and Gossypium nelsonii for cotton genetic improvement

Authors: ARSLANOVA, SEVARA - Uzbekistan Academy Of Sciences; ERNAZAROVA, ZIRAATKHAN - Uzbekistan Academy Of Sciences; ERNAZAROVA, DILRABO - Uzbekistan Academy Of Sciences; TURAEV, OZOD - Uzbekistan Academy Of Sciences; SUGIULINA, ASIYA - Uzbekistan Academy Of Sciences; TOSHPULATOV, ABDULQAHHOR - Uzbekistan Academy Of Sciences; KHOLOVA, MADINA - Uzbekistan Academy Of Sciences; AZIMOVA, LAYLO - Uzbekistan Academy Of Sciences; RAFIEVA, FERUZA - Uzbekistan Academy Of Sciences; GAPPAROV, BUNYOD - Uzbekistan Academy Of Sciences; KHALIKOV, KUVANDIK - Uzbekistan Academy Of Sciences; KHIDIROV, MUKHAMMAD - Uzbekistan Academy Of Sciences; ISKANDAROV, ABDULLOH - Uzbekistan Academy Of Sciences; KODIROV, DAVRON - Uzbekistan Academy Of Sciences; TURAEV, OBIDJON - Uzbekistan Academy Of Sciences; MAULYANOV, SALIKHJAN - Uzbekistan Academy Of Sciences; Udall, Joshua; Yu, John; KUSHANOV, FAKHRIDDIN - Uzbekistan Academy Of Sciences

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2025
Publication Date: 5/26/2025
Citation: Arslanova, S., Ernazarova, Z., Ernazarova, D., Turaev, O., Sugiulina, A., Toshpulatov, A., Kholova, M., Azimova, L., Rafieva, F., Gapparov, B., Khalikov, K., Khidirov, M., Iskandarov, A., Kodirov, D., Turaev, O., Maulyanov, S., Udall, J.A., Yu, J., Kushanov, F. 2025. Development and characterization of synthetic allotetraploids between diploid species Gossypium herbaceum and Gossypium nelsonii for cotton genetic improvement. Plants. 14(11). Article 1620. https://doi.org/10.3390/plants14111620.
DOI: https://doi.org/10.3390/plants14111620

Interpretive Summary: There have been declines in genetic advances for fiber yield and quality as well as biotic and abiotic stress tolerance in Upland cotton production. The cotton genus has many wild species that are potentially valuable sources of genetic variation for crop improvement. Tapping into rich genetic resources of the cotton genus becomes relevant, but introgression of desirable traits from the wild species into cultivated cottons is tedious, hindering the progress of exploiting wild cotton germplasm. In this study, we made several crosses between African diploid (G. herbaceum) subspecies and Australian diploid wild species (G. nelsonii), known for their adaptation to the adverse biotic and abiotic conditions, to produce interspecific diploid F1 hybrids that were genetically unstable. Upon colchicine treatment and analysis of chromosome doubling materials, we successfully produced allotetraploid F1 hybrids that were stable and fertile. Genomic and cytogenetic changes were observed in the segregating synthetic hybrids that seemed to have dominant inheritance from the Australian cotton in both direct and reciprocal crosses. Phenotypic characterization showed increased resistance to cotton aphid (Aphis gossypii Glover) and whitefly (Aleyrodidae) infestation in segregating cotton progeny. The novel synthetic allotetraploid cottons produced in this study would serve as valuable breeding sources in the introgression of important traits, including biotic and abiotic stress tolerance, into the elite Upland cotton varieties.

Technical Abstract: Cotton (Gossypium spp.) improvement relies on broadening the genetic base of cultivated varieties. This study aimed to enrich the Upland cotton G. hirsutum (AD1 genome) by developing and characterizing synthetic allotetraploids derived from the Afro-Asian species G. herbaceum (A1 genome) and the Australian wild species G. nelsonii (G3 genome). Interspecific hybrids were generated between various G. herbaceum subspecies (africanum, pseudoarboreum, pseudoarboreum f. harga, frutescens, and euherbaceum) and G. nelsonii. Chromosome doubling was successfully induced in F1 hybrids using colchicine (0.2%), resulting in fertile F1C allotetraploids (A1A1G3G3) specifically from the crosses of G. herbaceum subsp. euherbaceum × G. nelsonii and G. herbaceum subsp. frutescens × G. nelsonii. Cytogenetic analyses, including chromosome counts and meiotic studies, confirmed the allotetraploid nature of the F1C hybrids and demonstrated restored the fertile F1 compared to the sterile F1 hybrids. Notably, tetrad analysis revealed a significant reduction in meiotic abnormalities in the F1C hybrids. Molecular analysis using 192 SSR markers identified 74 polymorphic markers among the parental lines, and a subset of these markers confirmed the hybridity of the F1 and F1C progeny. Additionally, increased resistance to cotton aphid (Aphis gossypii Glover) 5.2–5.6% infestation in F1C hybrids vs. 22.1% in G. hirsutum Ravnak-1 and whitefly (Aleyrodidae) 5.4–5.8% infestation in F1C hybrids vs. 23.9 % in Ravnak-1 cultivar. Phylogenetic analysis based on SSR data clearly separated the G. herbaceum subspecies from the Australian wild species, highlighting the genetic divergence being bridged through these novel allotetraploids. Interestingly, both direct and reciprocal crosses revealed a dominant inheritance of G. nelsonii-derived traits in the F1C hybrids, regardless of its use as male or female parent, which was also reflected in their phylogenetic placement closer to G. nelsonii. Restored pollen viability in the F1C allotetraploid hybrids underscores their potential for breeding applications. These research results highlight the role of synthetic allotetraploids derived from G. herbaceum and G. nelsonii in broadening the genetic base of G. hirsutum and enhancing its resilience to biotic and abiotic stresses. These novel allotetraploids serve as bridges for introgressing wild-species traits, such as pest resistance and stress tolerance into elite cotton cultivars, addressing the genetic bottleneck in modern breeding programs.