ABSTRACT Rice ( Oryza sativa L.) is one of the most widely consumed cereal crops, serving as a staple food for billions of people worldwide. However, unpredictable climatic fluctuations and the continuous decline in cultivable land pose significant challenges to sustaining stable grain yields. As grain yield is a complex trait with low heritability, indirect selection through highly heritable yield‐component traits, particularly panicle architecture, offers a promising strategy to enhance rice productivity and contribute to global food security. In this study, 300 germplasm accessions selected from the 3K Rice Genome Panel were evaluated during Kharif 2023 for panicle length, panicle weight and number of grains per panicle using an alpha‐lattice design at Mandya and Gangavathi, Karnataka, India. Analysis of variance revealed substantial phenotypic variability for all evaluated traits. Phenotypic data integrated with genotypic information were subjected to genome‐wide association studies to identify genomic regions associated with panicle architecture traits. A total of 41 and 39 marker‐trait associations (MTAs) were identified using the FarmCPU and BLINK models, respectively. Nine MTAs were consistently detected across both models, three of which co‐localised with previously reported genes or QTL regions. Notably, 38 and 36 MTAs identified through FarmCPU and BLINK, respectively, represent potentially novel associations, highlighting key genomic regions for future validation and candidate‐gene discovery. Haplotype analysis of candidate genes revealed favourable allelic combinations associated with increased panicle length ( OsLP1 and OsGRRP ) and higher grain number per panicle ( Gn1a ). Furthermore, the significant SNPs identified in this study can be converted into breeder‐friendly KASP or CAPS markers following validation to facilitate marker‐assisted selection. Among the evaluated accessions, IRGC 647 (6.23 t/ha), IRGC 993 (6.13 t/ha) and IRGC 952 (6.02 t/ha) possessed putative favourable haplotypes across candidate genes for panicle architecture, representing valuable candidate donor lines for future functional validation and climate‐resilient rice breeding programmes.
ABSTRACT Multi‐environment trials (METs) are essential in breeding programmes to identify high‐performing and stable genotypes across different environments. However, trial sites are often chosen based on convenience rather than representativeness, which leads to reduced relevance to actual grower environments and inefficient resource use. This study developed a data‐driven framework to optimize MET site selection for US pickling cucumber ( Cucumis sativus L.) breeding under both current and future climate scenarios. In this context, we integrated multi‐location and multi‐year historical yield data with weather and soil‐derived environmental covariates (ECs). Feature selection identified 14 ECs associated with yield that captured the main spatial and temporal environmental gradients associated with cucumber yield. These ECs were then used to cluster the 11 major cucumber‐producing counties, which represent approximately 95% of US pickling cucumber harvested area, into three distinct environmental groups. Next, the heritability‐optimized strategy reduced the historical trial network from seven to three locations, while maintaining high Cullis heritability . Finally, to evaluate potential shifts in production‐environment structure under future growing conditions (2050–2065), we compared present‐day environmental clusters with projections for two future planting windows (March–June and April–July). Future climate projections indicated that Michigan, Wisconsin and Ohio counties are likely to remain environmentally similar, whereas California's San Joaquin County may become a distinct future environment. Overall, this framework improves MET design by combining environmental representativeness, genetic precision, production importance and future climate risk, providing a practical strategy for reducing redundant testing while maintaining coverage of current and future target production environments.
ABSTRACT Macauba ( Acrocomia spp.) is an underutilised palm, native to Brazil and other tropical regions of the Americas, with substantial potential for vegetable oil and bioenergy production. However, its long juvenile phase delays the identification of promising parents and hybrid combinations. This study characterised the early vegetative performance of 60 individual macauba hybrids derived from intraspecific Acrocomia aculeata crosses and an interspecific A. aculeata × Acrocomia totai cross. Seventeen traits related to plant architecture, leaf morphology and biomass were evaluated over 2 years (2023–2024) using a mixed model fitted by restricted maximum likelihood, with the year as a fixed effect and accession as a random effect. Repeatability, predicted accession effects, trait correlations, principal component analysis, hierarchical clustering and a composite vigour index were also examined. Considerable phenotypic and persistent among‐plant variation was observed, where the number of fallen leaves showed the highest phenotypic and among‐plant coefficients of variation (78.2% and 55.9%, respectively). Repeatability was moderate for all traits ( R = 0.42–0.52), except central pinna width ( R = 0.11). Fresh mass of pinnae was strongly correlated with dry mass of pinnae ( r = 0.90) and moderately correlated with other vegetative and biomass‐related traits, including central pinna length ( r = 0.67), indicating that fresh pinna mass may serve as a practical proxy for pinna dry mass. The first two principal components explained 61.9% of the multivariate variation, driven mainly by biomass and structural traits. The vigour index identified 10 putative hybrid candidates, with H19‐14, H20‐5 and H17‐9 receiving the highest scores. These outcomes provide useful phenotypic information for early screening in macauba, although the selected plants require further validation through replicated, multiyear evaluations that include fruit and oil‐production traits. This work offers a practical starting point for accelerating early‐stage selection in macauba breeding to enhance its productivity as a sustainable bioenergy crop.
ABSTRACT Phosphorus (P) deficiency remains one of the most critical factors restricting rice yield in India, with popular cultivars like MTU‐1121 particularly vulnerable to low‐P soils. To enhance P‐use efficiency while retaining the preferred grain and agronomic features of MTU‐1121, the OsPSTOL1 gene located within the Pup1 QTL was introgressed using marker‐assisted backcross breeding (MABB). Swarna (MTU‐7029), a high‐yielding variety possessing the Pup1 QTL, served as the donor parent. Foreground selection for Pup1 was conducted across F 1 , BC 1 F 1 and BC 2 F 1 generations using functional markers K20‐2 BspE1 and K46‐1. Background selection with 75 parental polymorphic SSR markers, combined with phenotype‐based selection, facilitated rapid recovery of the recurrent parent genome. A promising near‐isogenic line, WGL‐1487 [IET 28818 (RP 6317‐S35‐BC 2 F 4 ‐49‐25‐6‐21)], was identified at the BC 2 F 5 stage. WGL‐1487 was evaluated under the All India Coordinated Research Project on Rice (AICRPR) during the 2019 and 2021 wet seasons across P‐deficient and P‐sufficient environments. It consistently outperformed MTU‐1121 under low‐P conditions, demonstrating superior P‐use efficiency while maintaining comparable plant type, yield attributes and grain quality traits. The line exhibited 98.60% recurrent‐parent genome (RPG) recovery while retaining the target Pup1 locus and its medium‐slender grain type with desirable quality parameters, including 71.6% head rice recovery, 25.25% amylose content, 47‐mm gel consistency and an alkali spreading value of 7.0. Now released as Telangana Vari‐8, this variety serves as a suitable replacement for MTU‐1121 in P‐deficient ecologies. The variety has the potential to reduce phosphorus fertilizer requirements and improve productivity under phosphorus‐deficient conditions, thereby contributing to enhanced profitability for farmers.
ABSTRACT 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 × 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.
