HETEROSIS AND MUTATION BREEDING APPROACHES FOR GENETIC IMPROVEMENT OF CUCURBITACEOUS VEGETABLE CROPS

Abstract

Emamectin Benzoate (EB) is a novel pesticide designed for control of insects and mites in crops.  It is a semisynthetic avermectin derivative, belonging to the 16 – membered macrocyclic lactones, has widespread application in agriculture for pest management (1).  Avermectin, from which Emamectin Benzoate is derived, is produced through the fermentation of Streptomyces avermitilis (2).  The safety of avermectin compounds for mammals, including humans, stems from their limited ability to cross the Blood – Brain Barrier (BBB), the absence of glutamate – gated chloride channels in mammals, and the reduced affinity of avermectins for other ligand – gated chloride channels in mammals (3).  Emamectin Benzoate poisoning can present with severe symptoms, surpassing initial expectations, leading to manifestations such as altered consciousness, inhalation pneumonia and gastrointestinal (GI) symptoms (4).  We present a rare case of Emamectin Benzoate toxicity in a puppy and its successful management with Intravenous Lipid Emulsion (ILE).Cucurbitaceous vegetable crops constitute an important group of horticultural species widely cultivated for their nutritional, economic, and medicinal value. Enhancing productivity, quality, and resilience to biotic and abiotic stresses in these crops remains a major objective of plant breeding programs. Heterosis (hybrid vigor) has been extensively exploited in cucurbits to improve traits such as fruit yield, size, earliness, uniformity, and resistance to diseases and environmental stresses. Development of high-performing hybrids through intra-specific and inter-specific hybridization has significantly contributed to commercial vegetable production worldwide.Mutation breeding represents another powerful approach for generating novel genetic variability through the use of physical and chemical mutagens such as gamma rays and ethyl methane sulfonate (EMS). Induced mutations have facilitated the development of improved genotypes possessing desirable traits including dwarf growth habit, altered sex expression, improved fruit characteristics, and enhanced tolerance to stresses. Recent advancements in molecular breeding and genome editing tools such as CRISPR/Cas9 have further increased the precision and efficiency of mutation breeding, enabling targeted modification of genes controlling economically important traits. The integration of heterosis breeding with induced mutagenesis and modern genomic tools offers significant potential for accelerating genetic improvement in cucurbitaceous vegetable crops. These combined approaches can contribute to the development of high-yielding, climate-resilient, and nutritionally improved cultivars, thereby supporting sustainable vegetable production and food security.