“Breeding for Powdery Mildew in Chilli”

UNIVERSITY OF AGRICULTURAL SCIENCES, RAICHUR

College of Agriculture, Raichur

Department of Genetics and Plant Breeding

2nd Seminar (Master’s Degree)

“Breeding for Powdery Mildew in Chilli”

    Chilli is an economically important vegetable-cum-spice crop belonging to the family Solanaceae, which also includes potato, tomato, eggplant, petunia, and tobacco. The Solanaceae family encompasses more than 3,000 species, most of which share the same chromosome number (n = 12) but vary considerably in genome size. Peppers (Capsicum spp.) are utilized as vegetables, condiments, spices, medicines, coloring agents, and sources of vitamins. The most common cultivated species include Capsicum annuum, Capsicum frutescens, Capsicum chinense, Capsicum pubescens, and Capsicum baccatum. Despite their economic potential, chilli crops are vulnerable to several pathogens, including fungi, bacteria, and viruses, leading to significant yield losses. Among these, powdery mildew (PM), caused by Leveillula taurica, is one of the most devastating fungal diseases (Lefebvre et al., 2003).

    Tembhurne and Kisan (2020) evaluated cytoplasmic-genic male sterile (CGMS) parents and identified powdery mildew-resistant genotypes in chilli. The hybrid UARChH42 recorded significantly higher mean dry fruit yield compared to the commercial hybrid Sitara across station, multilocation, and farm trials. Hybrids UARChH42 and UARChH43 showed highly resistant and resistant reactions to powdery mildew, respectively.

    Wankhade and Wadikar (2018) developed sequence-characterized amplified region (SCAR) markers using an F₂ mapping population derived from a cross between a resistant parental line (‘Odisha Local’) and a susceptible line (‘9907-9611’). The nucleotide sequence obtained from ‘Odisha Local’ using the OPA15 primer showed partial identity with the RPP13-like disease-resistant protein. These molecular markers are highly valuable for indirect selection of resistant plants in chilli breeding programs.

    Ahn et al. (2018) carried out genome-wide identification of single nucleotide polymorphism (SNP) markers associated with PM resistance in Capsicum baccatum and Capsicum annuum. Their results revealed chromosome-wise distribution of SNPs, with resistance-related SNPs predominantly located on chromosome 4. A total of 6,281 SNPs associated with 46 resistance genes were identified, with PRH1 showing the maximum polymorphic SNPs linked to NBS-LRR genes. Validation using HRM assays in 45 F₄ populations confirmed strong correlation with phenotypic resistance.

    The breeding of powdery mildew-resistant chilli varieties requires a multifaceted strategy integrating conventional and molecular approaches. Classical breeding techniques, involving careful selection and hybridization of resistant genotypes, can be complemented by genomic tools such as marker-assisted selection (MAS). The incorporation of diverse germplasm sources further enhances the durability of resistance. Advanced techniques like genome-wide SNP identification and molecular markers expedite resistance breeding, while new technologies such as CRISPR/Cas gene editing may further strengthen future strategies.

    Through integrated efforts, the development of powdery mildew-resistant chilli varieties can ensure sustainable chilli production, minimize yield losses, and enhance the resilience of this economically significant crop.

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References

• Ahn, Y.K., Manivannan, A., Karna, S., Jun, T.H., Yang, E.Y., Choi, S., Kim, J.H., Kim, D.S. and Lee, E.S., 2018. Whole genome resequencing of Capsicum baccatum and Capsicum annuum to discover single nucleotide polymorphism related to powdery mildew resistance. Sci. Rep., 8(1): 5188.

• Lefebvre, V., Daubèze, A.M., Rouppe van der Voort, J., Peleman, J., Bardin, M. and Palloix, A., 2003. QTLs for resistance to powdery mildew in pepper under natural and artificial infections. Theor. Appl. Genet., 107(4): 661–666.

• Tembhurne, B.V. and Babu, K., 2020. Development of male sterility-based powdery mildew-resistant high-yielding F₁ hybrid in chilli (Capsicum annuum L.). Front. Crop Improv., 8(1): 31–33.

• Wankhade, R.R. and Wadikar, M.S., 2018. Identification of sequence-characterized amplified region (SCAR) markers linking resistance to powdery mildew in chilli pepper (Capsicum annuum L.). Afr. J. Agric. Res., 13(49): 2771–2779.