Tomato spotted wilt virus (TSWV) and late leaf spot (LLS) are among the major constraints to peanut production. Cultivated peanut has narrow genetic bases and lacks strong sources of resistance. Wild species, on the other hand, harbor diverse and strong resistances to multiple pathogens. In this study, we evaluated advanced breeding lines carrying introgressions from multiple wild Arachis species (A. stenosperma, A. batizocoi, A. valida, and A. cardenasii) across three contrasting field environments and experimental designs in Georgia, USA using complementary incidence- and severity-based phenotyping. Genotype effects were highly significant for both diseases. Several wild-derived lines -particularly those from A. stenosperma ancestry- showed strong and stable TSWV resistance across environments. Interestingly, some lines lacking detectable wild segments also showed high resistance to TSWV, suggesting cryptic or undetected introgressions. LLS resistance was primarily associated with the characteristic A. cardenasii segments on A02 and A03, and lines stacking these introgressions consistently outperformed both cultivated parents and Georgia-06G, the most popular cultivar in the USA. Correlations between TSWV and LLS responses were weak, confirming genetic independence and emphasizing the need to screen both traits. A small subset of lines combined resistance to both diseases, and many also retained resistance loci to root-knot nematode (RKN), expanding their value as multi-trait donors. These findings demonstrate the power of wild introgression breeding for enhancing disease resistance and provide a foundation for deploying stacked alleles through marker-assisted and multi-environment selection.
These findings uncover new QTLs for PM resistance in strawberry, including on fruit, and provide validated strategies for breeding disease-resistant cultivars.
Alexandre Prohaska, Pol Rey-Serra, J. Bénéjam et al.· Horticulture Research· 0 citations
Bacterial wilt caused by Ralstonia solanacearum is a destructive disease severely restricting tomato (Solanum lycopersicum L.) productivity in tropical and subtropical regions. The purpose of this study was to identify novel sources of resistance and explicate the inheritance pattern of bacterial wilt resistance in tomato. A total of 59 genotypes, including open-pollinated lines, hybrids and breeding accessions, were subjected to screening experiments during two consecutive seasons (2022–2023 and 2023–2024) under controlled net house conditions at Centurion University of Technology and Management and natural epiphytotic field conditions at Indian Institute of Horticultural Research - Central Horticultural Experiment Station , Bhubaneswar, India. Disease severity was evaluated using percent disease index (PDI) and area under disease progress curve (AUDPC). The open-pollinated cultivar ‘Utkal Kumari (BT-10)’ exhibited consistent high resistance, with significantly lower AUDPC values (<150 vs >1800 in susceptible checks) and high survival rates (90 %) across environments. Among others, tomato cultivars Arka Samrat, Arka Abhed and JK Desi, demonstrated significant resistance while genotypes such as Pusa Ruby and EW815 were consistently highly susceptible. A segregating F₂ population derived from a cross between resistant ‘BT-10’ and susceptible ‘Pusa Ruby’ exhibited continuous variation in disease response. Chi-square analysis revealed significant deviation from a 3:1 Mendelian segregation ratio (χ² = 72.30, P < 0.01), indicating a quantitative mode of inheritance. These findings highlight the potential of Utkal Kumari and allied resistant lines as donors for resistance breeding and emphasize the need to integrate robust phenotypic screening with molecular approaches for durable and strategic bacterial wilt management in tomato.
D. Debasmita, D. Sunanya, N. P. Bhagbat et al.· Plant Science Today· 0 citations
The results indicate that the genetic architecture of corn in response to MaYMV is complex, and that developing immune cultivars may not be achievable using natural sources of genetic variation, but this study provides a foundation for breeding maize with improved tolerance and advances the understanding of host response to MaYMV infection.
Erik W. Ohlson, Christopher A. Nacci, Nitika Khatri et al.· bioRxiv· 0 citations
Bacterial leaf blight (BLB) of rice, caused by Xanthomonas oryzae pv. oryzae, is a major constraint on rice production, and the use of resistant genotypes is an important approach to disease management. The present study screened 40 rice genotypes for BLB resistance using morphological evaluation and molecular markers linked to seven resistance genes: xa5, Xa7, xa8, Xa10, xa13, Xa21 and Xa33. Field screening was conducted at RARS, Maruteru, during kharif 2023 using artificial inoculation by the leaf-clipping method, and disease reactions were assessed according to the Standard Evaluation System. Morphological screening categorised entries as highly resistant, resistant, moderately resistant, susceptible or highly susceptible according to diseased leaf area. Molecular screening was performed using gene-linked markers to determine the presence of the target resistance genes. Nineteen genotypes were identified as carrying two or three BLB resistance genes. Phenotypic evaluation based on diseased leaf area showed variation in resistance among the 40 genotypes and supported the molecular screening results. Jaavepula-2, Basmati, Tulasi baso and Kundadam-2 carried three resistance genes, while Kalamuch and Loyamalli carried the Xa7 and Xa21 combination and exhibited phenotypic resistance. The combined morphological and molecular screening therefore identified rice genotypes with multiple BLB resistance genes that may serve as donor parents in marker-assisted breeding programmes aimed at improving BLB resistance in rice.
J. Mounika, B. Veni, Rani Chapara et al.· Asian Research Journal of Ag...· 0 citations