Screening of Onion (Allium cepa L.) Genotypes for Waterlogging Tolerance

Abstract

Onion production is severely affected by waterlogging conditions, which are created due to heavy rainfall. Hence, the identification of waterlogging-tolerant onion genotypes is crucial for increasing onion production. In the present study, 100 distinct onion genotypes were screened for waterlogging tolerance under artificial conditions by using the phenotypic approach in the monsoon season of 2017. Based on plant survival and recovery and changes in bulb weight, we identified 19 tolerant, 27 intermediate tolerant, and 54 highly sensitive onion genotypes. The tolerant genotypes exhibited higher plant survival and better recovery and bulb size, whereas sensitive genotypes exhibited higher plant mortality, poor recovery, and small bulb size under waterlogging conditions. Furthermore, a subset of 12 contrasting genotypes was selected for field trials during monsoon seasons 2018 and 2019. Results revealed that considerable variation in the morphological, physiological, and yield characteristics were observed across the genotypes under stress conditions. Waterlogging-tolerant genotypes, namely, Acc. 1666, Acc. 1622, W-355, W-208, KH-M-2, and RGP-5, exhibited higher plant height, leaf number, leaf area, leaf length, chlorophyll content, membrane stability index (MSI), pyruvic acid, antioxidant content, and bulb yield than sensitive genotypes under stress conditions. Furthermore, the principal component analysis biplot revealed a strong association of leaf number, leaf area, chlorophyll content, MSI, and bulb yield with tolerant genotypes under stress conditions. The study indicates that the waterlogging-tolerant onion genotypes with promising stress-adaptive traits can be used in plant breeding programs for developing waterlogging-tolerant onion varieties.

Onion Biofortification Using Selenium Bionanofertilizer and its Bulk Source under Sandy Soil Conditions

“…(Foliar or soil or in vitro application). As so far as we know, few articles published on onion biofortified with different nutrient such as Se [50,1], and Zn [52], but there is no published article on biofortifying onion with Se under nutrient deficiency stress. I In the current study, different sources of Se-fertilizers were applied for biofortification of onion under sandy soil conditions.…”

“…Onion (Allium cepa L.) is considered a vital vegetable crop for human health, which globally cultivated across 4.3 million ha with a total production of 98 million tons [1]. The main five producer of global onion production are China, India, the USA, Egypt, and Turkey, the first two countries can produce around 50% of global production [2].…”

Seed Priming Applied to Onion-Like Crops: State of the Art and Open Questions

“…Sensitivity to oxygen deficiency and mechanisms for metabolic adaptation to low oxygen in germinating seeds is dependent on several molecular factors, e.g., ROS levels and the balanced activity of ROS producing and ROS scavenging enzymes [60]. These issues need to be urgently explored in onion and onion-like crops, considering the impact of waterlogging conditions caused by heavy rainfall in sensitive regions [61]. Different priming agents (KCl, KH 2 PO 4 , CaCl 2 and PEG 8000) were tested on seeds of the leek cultivars Lungo della Riviera and Monstrueux de Carentan [62].…”

Elucidating the molecular responses to waterlogging stress in onion (Allium cepa L.) leaf by comparative transcriptome profiling

“…To attain adequate onion production during monsoons, genotypes that can withstand short or prolonged waterlogging conditions must be identified. In our previous study, we screened diverse onion genotypes for waterlogging tolerance and then grouped them as tolerant and sensitive based on their phenotypic and physiological traits ( Gedam et al., 2022 ).…”

“…The present study compared the waterlogging-tolerant onion genotype with the sensitive one at the transcriptional level to identify waterlogging tolerance-associated key genes and related pathways. Both genotypes were selected based on previous findings of phenotypic and biochemical responses under the waterlogging condition ( Gedam et al., 2022 ). To the best of our knowledge, this study is the first to investigate the molecular mechanism underlying waterlogging tolerance in onion.…”