The widespread development of insecticide resistance and stricter regulations on pesticide use highlight the need for natural pest resistance in crops. In pepper, viral diseases such as pepper yellow leaf curl virus (PepYLCV), transmitted by the whitefly Bemisia tabaci, are a major constraint in tropical regions. In this study, we explored genetic variation within Capsicum spp. to identify sources of resistance against B. tabaci Asia I and assessed whether plant resistance is associated with reduced PepYLCV disease. Eleven accessions were screened in no-choice and choice assays using viruliferous and nonviruliferous whiteflies for host acceptance, survival, oviposition and development and evaluated for disease symptoms and PepYLCV presence under semi-natural field infestation. Plant accession was the main factor determining whitefly performance. Capsicum annuum CA9, previously identified as resistant to B. tabaci MEAM1, was among the least preferred by whitefly adults and was associated with low population growth of B. tabaci Asia I. Several other accessions, including CA6 and CA8, and Capsicum chinense CC35, also showed reduced whitefly performance relative to susceptible accessions although the magnitude varied across assays and treatments. Differences between whitefly treatments were secondary and species dependent: Adult emergence was higher with viruliferous whiteflies on all C. annuum accessions but higher with nonviruliferous whiteflies on all C. chinense accessions, supported by a significant species & times; treatment interaction. Because the two whitefly treatments also differed in age and feeding history, these differences are interpreted as between-treatment effects rather than effects of the virus itself. In the field, CA9 and several other accessions, notably CC35, remained at very low disease incidence. Overall, we identify promising candidate genetic resources for breeding pepper with reduced susceptibility to B. tabaci and lower associated disease, although the present field design cannot separate reduced vector performance from direct effects on the virus, which should be further studied.
Guar (Cyamopsis tetragonoloba L. Taub.), a resilient legume valued for its galactomannan-rich seeds used in industrial applications, exhibits limited productivity due to limited genetic diversity and insufficient breeding efforts. This study aimed to dissect the genetic architecture of yield-related traits using quantitative trait loci (QTL) mapping in a recombinant inbred line (RIL) population comprising 128 F-2:8 lines derived from high (TAMG149) and low (TAMG343) seed-yielding parents. Field experiments were conducted in Vernon, Texas, across two seasons (2023 and 2024) using a randomized complete block design with three blocks to evaluate seed yield, pod number per plant, pod harvest index (PHI) and pod length. Phenotypic analyses revealed significant genotypic variation, with seed yield ranging from 145.73 to 3628.68 kg ha(-1) (mean 1409.42 kg ha(-1), CV 38.96%), and strong positive correlations between yield and pod number (r = 0.65, p < 0.0001) as well as PHI (r = 0.37, p < 0.0001). A total of 381 filtered single nucleotide polymorphisms (SNPs) obtained from genotyping-by-sequencing (GBS) were used to generate the genetic maps spanning 1197.7 cM (average inter-marker distance, 3.05 cM). Composite interval mapping (CIM) identified 40 QTLs across traits and environments, including stable loci for seed yield on Chromosomes 2 (Ct_yd_2, R-2 = 9.19%) and 6 (Ct_yd_6, R-2 = 0.95%), pod number on Chromosomes 2 and 5, PHI on Chromosomes 1, 5 and 6, and pod length on Chromosomes 3, 5, 6 and 7. These findings highlight pod number as the primary yield driver, with stable QTLs offering robust targets for marker-assisted selection to enhance guar productivity. This is the first study on linkage map construction and QTL mapping for yield and yield components in guar.
ABSTRACT Oil palm ( Elaeis guineensis ) accounts for the largest part of global edible oil production, and its genetic improvement is one of the main levers to increase yields while minimizing the social and environmental impacts. The oil palm breeding scheme implemented by PalmElit and its partners relies on the exploitation of the general combining abilities (GCAs) of parent palms from two heterotic groups. The GCAs are estimated for complex yield‐related traits through incomplete factorial mating designs planted in large‐scale trials. A total of 140 parents from the heterotic group A (GA) and 150 parents from the heterotic group B (GB) were evaluated through 450 test crosses assessed over a 9‐year period for 12 yield‐related traits. Breeding values (BVs) were estimated as pedigree‐based best linear unbiased predictions (P‐BLUP) using linear mixed models integrating pedigree information. Parental BVs were used to generate the best possible outcomes for A × B commercial hybrid production. The 45 best predicted combinations from the 10% best parents gave an adult yield ranging from 8.9 to 9.6 t crude palm oil (CPO) ha −1 yr. −1 which represents a genetic gain of 21.3% compared to the mean of all trialled crosses. In comparison, genetic progress obtained from the 10% best trialled crosses only reached 10.7% demonstrating the advantage of a breeding strategy based on accurate parental BV estimation and cross prediction. Overall genetic progress on oil yield in the best predicted crosses was found to be mostly attributable to the improvement of the oil extraction rate (OER), which averaged 29.2% due to the stringent pre‐selection on bunch quality traits applied to the parents. In addition, the genetic parameters calculated for all measured traits were used to characterize the breeding populations of restricted origins (BPROs) within both heterotic groups and define an optimal recombination strategy.
ABSTRACT Winter rye is the tallest small‐grain cereal and consequently more prone to lodging. Plant growth regulators are routinely used in commercial production to reduce the risk of lodging. To select genotypes with better tolerance to stem lodging despite its incidental character, we tested the use of a provocation trial with higher nitrogen level, no/less plant growth regulators for 16 varieties and 22 experimental hybrids and compared the results with a standard yield trial in 2024. The provocation trial yielded higher lodging scores (score 5.1 vs. 3.8) with comparable heritabilites ( h 2 = 0.75 vs. 0.72, respectively). The correlation between both trials was r = 0.88 ( p < 0.001) for plant height and r = 0.57 ( p < 0.001) for stem lodging at harvest. To estimate genotypic variation among genetic resources (GR), 118 testcrosses of international origin were analysed in a provocation trial in 2025 and compared with a set of commercial entries. Each of these experiments was conducted across three to four locations. Across all experiments, lodging tolerance ranged from 1.1 to 8.3, spanning nearly the entire 1–9 range. Significant genotypic variance was found among the GR testcrosses and standard entries. The best testcrosses with GR exhibited a lodging tolerance similar to that of the best experimental hybrid (score 3.2 vs. 2.8). In conclusion, some entries that could be used to further breed for lodging tolerance were found among the landraces and old varieties. The provocation trial should be supplemented by a subsequent yield trial for the selected entries to account for standard agronomic conditions.
ABSTRACT Limited water availability coupled with increasing soil salinity poses a major challenge to sustainable turfgrass growth and performance. Dactylis glomerata L. (orchardgrass) is a widely distributed cool‐season perennial grass traditionally valued for forage production, with increasing interest in its potential as an alternative low‐input turf‐type species for water‐ and salt‐limited environments. However, despite its adaptability and stress tolerance, information on the salinity resilience and turf‐related performance of orchardgrass genotypes under field conditions remains limited. To address this gap, a worldwide collection of orchardgrass genotypes was evaluated for salinity tolerance, forage yield, agro‐morphological traits and turf quality. Field assessments were conducted across five harvests during the 2022 and 2023 growing seasons under both normal and saline stress conditions, providing comprehensive insights into their morphological and agronomic responses. On average, salinity reduced dry forage yield, colour, ground coverage and turf density by 53.39%, 47.90%, 52.49% and 37.35%, respectively. Considerable genetic variation was observed for the measured traits under both conditions. Broad‐sense heritability ranged from 0.29 to 0.67 under normal irrigation and from 0.35 to 0.54 under salinity stress. Under both salinity conditions, the summer harvest produced the lowest forage yield and turf quality compared with spring and autumn cuts, consistent with seasonal growth suppression and possible partial summer dormancy with considerable variation among genotypes in the panel. Positive correlations among crown diameter, plant height, leaf length, colour, coverage, density and stress tolerance index with forage yield suggest the potential for simultaneous selection targeting both forage productivity and turf quality within this germplasm. Multivariate analysis enabled the identification of suitable genotypes offering promising candidates for future breeding programmes aimed at developing new cultivars.
