In the heart of Zhejiang Province, a team of researchers led by Dr. Zhang Chenglei from the Taizhou Key Laboratory of Horticultural Biotechnology is reviving a local citrus treasure, the Bendizao tangerine, and potentially transforming the regional fruit industry. Their work, recently published in *Guoshu xuebao* (Acta Horticulturae Sinica), focuses on creating seedless varieties of this prized fruit, a development that could bolster the commercial prospects of Huangyan Miju, a regional brand known for its tangy, sweet tangerines.
The Bendizao tangerine, once a staple in Huangyan, has faced decline due to long-term asexual propagation, leading to reduced yield and quality. “The introduction of seedless varieties from abroad over the past few decades has further diminished its production and planting area,” explains Dr. Zhang. To combat this, his team turned to polyploid breeding, a technique that involves manipulating the number of chromosome sets in a plant to create new varieties with desirable traits.
The researchers employed two main strategies: exploring polyploids from seedlings based on morphological traits and producing triploids through interploidy hybridization. “We collected over 1500 mature fruits and obtained more than 7500 seeds,” Dr. Zhang details. From these, they screened 51 suspected polyploids, ultimately identifying 23 tetraploids and one triploid through flow cytometric analysis. Additionally, they conducted interploidy crosses using Bendizao tangerine as the female parent and a sexual allotetraploid hybrid as the male parent. This resulted in 78 regenerated plants, eight of which were confirmed to be triploids.
The genetic origin of these polyploids was further verified using SSR markers. “Among the polyploids identified from the seedlings, 19 tetraploids exhibited an identical band pattern to that of Bendizao tangerine, suggesting that they might originate from the natural doubling of nucellar cells in Bendizao tangerine,” Dr. Zhang notes. The remaining polyploids showed additional bands, indicating they were likely sexual hybrids.
The creation of these novel polyploid germplasms holds significant promise for the seedless breeding of Bendizao tangerine and for enhancing the fruit quality of Huangyan Miju. “This research not only provides a valuable material foundation for the seedless breeding of Bendizao tangerine but also offers a model for other citrus varieties facing similar challenges,” Dr. Zhang asserts.
The implications of this work extend beyond Huangyan. As consumer demand for seedless fruits continues to grow, the techniques developed by Dr. Zhang’s team could be applied to other citrus varieties, potentially revolutionizing the global citrus industry. Moreover, the use of polyploid breeding could lead to the development of new fruit varieties with improved traits, such as enhanced flavor, increased disease resistance, and better adaptability to changing climates.
In the words of Dr. Zhang, “This is just the beginning. The potential of polyploid breeding in citrus is vast, and we are excited to explore its full potential to benefit both the industry and consumers.” As the world watches, the humble Bendizao tangerine might just become the catalyst for a citrus revolution.