Diversity across Ploidy Levels in Mulberry (Morus spp.): A Review of Genetic Resources and Their Utilization

Authors: Y Surjalata Devi; Anowar Hossain
Diversity across Ploidy Levels in Mulberry (Morus spp.): A Review of Genetic Resources and Their Utilization
DOI
10.25125/ijoear-mar-2026-38
DIN
IJOEAR-MAR-2026-38
Abstract

Mulberry (Morus spp.) is an economically important perennial crop that serves as the primary food source for the domesticated silkworm (Bombyx mori) and also has potential for fruit production and the utilization of bioactive compounds. This genus exhibits considerable diversity in species characteristics, geographical distribution, chromosome number, and ploidy levels, providing valuable genetic resources for crop improvement. This review surveys mulberry species diversity, chromosome number and genome size variation, and the utilization of genetic resources in the development of improved cultivars. It further summarizes varieties developed through selection, hybridization, mutation breeding, and the use of polyploid germplasm, with emphasis on leaf productivity, environmental adaptation, and suitability for different silkworm-rearing requirements. In addition, reported genes associated with responses to drought, salinity, cold, heat, and powdery mildew are discussed in relation to their potential applications in stress-tolerance improvement. Despite this diversity, mulberry breeding faces challenges associated with variable ploidy levels, high heterozygosity, and long breeding cycles. Integrating conventional breeding with genomics, tissue culture, and emerging genome-editing technologies may help overcome these constraints and facilitate the development of productive, stress-tolerant, and multipurpose cultivars. Overall, this review highlights the importance of conserving and effectively utilizing mulberry genetic resources to support sustainable sericulture and broader agricultural and industrial applications.

Keywords
Morus genetic diversity ploidy mulberry stress tolerance sericulture.
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Introduction

Mulberry (Morus spp.) is an ancient, perennial, deciduous plant belonging to the family Moraceae. The genus is widely distributed across Asia and other regions, with considerable diversity among its wild and cultivated forms. East Asia and the Himalayan region are important areas of mulberry diversity. Several species, including Morus indica, M. alba (white mulberry), M. serrata (Himalayan mulberry), and M. laevigata, occur in different geographical regions of India [17], [24]. Mulberry is cultivated primarily for its leaves, which provide the principal food source for the domesticated silkworm (Bombyx mori). During its larval development, the silkworm feeds on mulberry leaves and subsequently spins a cocoon from which raw silk is extracted. Silk production and quality are influenced by leaf quality and the silkworm strain used, including multivoltine, bivoltine, and their hybrids [8], [9]. Beyond sericulture, mulberry fruits are valued for their nutritional and phytochemical constituents, including anthocyanins, antioxidants, fatty acids, and vitamins [11]. Mulberry leaves are also used in health beverages and animal feed because they contain bioactive compounds such as flavonoids, phenolic compounds, and coumarins, which have been investigated for potential health benefits [6], [22].

The genus Morus exhibits considerable variation in leaf morphology, growth characteristics, reproductive biology, fruit traits, and environmental adaptability [30]. This diversity provides valuable opportunities to identify desirable traits and broaden the genetic base of cultivated mulberry. However, the breeding potential of individual species depends on their agronomic characteristics, environmental adaptation, and reproductive compatibility with existing breeding materials. Systematic characterization and evaluation of mulberry genetic resources are therefore essential for identifying suitable material for specific improvement objectives.

Advances in molecular biology and genomics have created further opportunities for mulberry improvement. Research has identified genes associated with responses to abiotic stresses, including drought, salinity, cold, and heat, as well as biotic stresses such as powdery mildew. Understanding the functions of these genes may facilitate the identification and validation of genetic targets for developing stress-tolerant cultivars [19]. Integrating this knowledge with conventional breeding and emerging biotechnological approaches may help address challenges associated with mulberry productivity, environmental adaptation, and disease resistance.

In this context, the present review examines the genetic diversity of Morus species, focusing on geographical distribution, chromosome number, ploidy variation, and genome size. It also summarizes improved mulberry varieties and their utilization, discusses reported stress-responsive genes, and considers the major challenges and future opportunities for integrating conventional breeding with modern biotechnological approaches. The overall aim is to highlight how the conservation and effective utilization of mulberry genetic resources can contribute to the development of productive, stress-tolerant, and multipurpose cultivars for sustainable sericulture and broader agricultural and industrial applications.

Conclusion

Mulberry (Morus spp.) exhibits considerable diversity in chromosome number, ploidy level, genetic characteristics, and potential utilization, providing valuable resources for sericulture, fruit production, and bioactive-compound development. Improved varieties demonstrate how this diversity can be utilized to enhance leaf productivity, meet the feeding requirements of silkworms at different developmental stages, and adapt cultivation to diverse environments. In addition, studies of stress-responsive genes have identified potential molecular targets for improving tolerance to abiotic stresses and diseases. Nevertheless, challenges associated with ploidy variation, high heterozygosity, reproductive biology, and long breeding cycles remain important constraints. Integrating conventional breeding with genomics, tissue culture, and emerging genome-editing technologies may help improve the identification and utilization of valuable genetic resources. Such an integrated approach could contribute to the development of productive, resilient, and multipurpose mulberry cultivars for sustainable sericulture and broader agricultural and industrial applications.

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