Editorial: From Classical Breeding to Modern Biotechnological Advancement in Horticultural Crops -Trait Improvement and Stress Resilience, Volume II

PANKAJ KUMAR ^1* Mohammed Wasim Siddiqui ² Mohammad Irfan ^3*

• ¹ Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Himachal Pradesh, India
• ² Bihar Agricultural University, Bānka, Bihar, India
• ³ School of Integrative Plant Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, United States

The global challenge of securing food and nutrition against the backdrop of climate change demands urgent and innovative approaches to agricultural practices. As the planet faces increasing environmental pressures, the need for robust and resilient crops that can withstand these changes is more critical than ever (Irfan et al. 2023). Issues such as reduced yields, poor quality, and increased vulnerability to pests and diseases threaten global food systems, requiring urgent intervention. In this context, the transition from classical breeding methods to modern biotechnological advancements has revolutionized the approach to horticultural crop improvement (Kumar et al. 2023). This special issue, "From Classical Breeding to Modern Biotechnological Advancement in Horticultural Crops -Trait Improvement and Stress Resilience, Volume II," brings together 14 research articles and one review that highlight significant strides in improving horticultural crops resilience, quality, and nutritional content through genetic innovations. This is the second volume of our special issue on the transformative journey of crop breeding, specifically targeting trait improvement and resilience under stress conditions. Historically, horticultural crops such as fruits, vegetables, and ornamental plants have played an essential role in human nutrition and environmental enhancement. The classical methods of breeding, primarily involving hybridization, mutation breeding, and selection, were fundamental in improving key traits such as yield, size, and disease resistance. However, these methods often faced limitations due to their time-consuming nature and the complexity of the genetic mechanisms involved. The need for faster, more precise improvements led to the development and application of molecular genetics and biotechnological tools.The application of biotechnology has led to substantial progress in the improvement of traits related to yield, quality, and stress resilience. The genetic basis of key horticultural traits plays a fundamental role in crop improvement. Fruit color, a major determinant of consumer preference, is influenced by specific genetic loci. Feng et al. utilized BSA-seq technology to identify quantitative trait loci (QTLs) governing green and mature fruit color in pepper. They found that premature green and pale-green colors were controlled by loci on chromosomes 1 and 10, while mature fruit color was regulated by a recessive allele on chromosome 6. This genetic insight facilitates marker-assisted breeding to develop pepper varieties with desirable fruit color characteristics. Another essential trait in horticultural crops is the bright green leaf (BGL) trait, which enhances the commercial appeal of Chinese kale. Zhang et al. mapped and cloned the BoBGL gene using BSR-Seq and molecular marker analysis. The candidate gene, BoCER1.C8, was associated with wax synthesis, and variations in its promoter region influenced leaf color expression. Their findings provide a foundation for breeding new Chinese kale varieties with superior leaf aesthetics and market value.Likewise, in the case of fruit size, studies such as Pan et al. using quantitative trait loci sequencing (QTL-seq) in jujube have identified key genes associated with fruit size, which will be crucial for future breeding programs aimed at optimizing fruit production. Candidate intervals for jujube fruit size were primarily located on chromosomes 1, 5, and 10, with chromosome 1 being the most frequent. QTL-seq and ANNOVAR analysis identified 40 candidate genes from 424 SNPs and 164 InDels, including 37 annotated genes in the jujube genome (Pan et al.). These advancements, coupled with sustainable horticultural practices can meet the increasing demand for food while adapting to changing environmental conditions.Another exciting avenue of research is the exploration of genetic resistance to biotic stresses. One of the most pressing challenges faced by horticultural crops is their vulnerability to environmental stresses, including drought, salinity, extreme temperatures, and diseases (Sharma et al. 2022). Traditional breeding methods often fall short in developing varieties with the required level of resilience under these harsh conditions. In contrast, biotechnological interventions, such as the identification and deployment of stress-resilient genes, offer a promising solution. Enhancing crop resilience against biotic stress is critical for sustainable While biotechnology plays a crucial role in improving crop traits and resilience, it must be integrated with sustainable agricultural practices to ensure long-term success. The development of climate-resilient crops requires a multi-faceted approach that combines genetic innovations with sustainable farming techniques (Kumar et al. 2023). This synergy can create agricultural systems that are both productive and environmentally friendly. The importance of this integrated approach is highlighted in the work of Kelimujiang et al., who examined the WRKY gene family in Lavandula angustifolia (LaWRKY), a key plant in the essential oils industry.The LaWRKY plays key roles in growth, stress responses, and secondary metabolism, with 207 members identified through bioinformatics analysis. Phylogenetic analysis classified LaWRKY into three groups, with segmental duplications driving gene family expansion. Tissue-specific expression revealed 12 genes highly active in flower buds and calyx, suggesting involvement in terpenoid biosynthesis. Environmental stressors regulated LaWRKY expression, with light and cold inducing flower bud expression, while drought primarily affected leaves. Overall, the research presented in this issue highlights the transformative role of biotechnology in modern crop improvement. From enhancing resilience to optimizing nutritional content, the future of horticultural crops lies in the synergy between classical breeding methods and modern genetic innovations. These efforts will pave the way for the development of crops that not only survive but thrive under the changing conditions of our planet, ensuring food and nutritional security for all. We appreciate Frontiers in Plant Science for hosting this Research Topic and extend our gratitude to all contributors and reviewers for their valuable insights.