Climate resilience vis-a-vis G× E interaction studies in Brassica under different microclimatic systems
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Date
2022-02
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G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145
Abstract
Climate change is a serious concern in current times. The impact of it can be clearly seen in risingearth’s surface temperature, melting of glaciers, floods, draughts, and more importantly deposition of greenhouse gases in the troposphere. Thus a climate smart approach is required to counter the impacts of changing climate. Agroforestry is a land use strategy that offers the only way to achieve both climate change adaptation and mitigation goals at the same time. In India, the principal oilseed crops are Brassica spp., Rapeseed-mustard, which provides edible oils, vegetables, animal feed, sauces, and industrial lubricants. Indian mustard was discovered to be vulnerable to change in carbon dioxide (CO2) and temperature.The present investigation was taken up during 2018-2021 in the Department of Genetics & Plant Breeding at GBPUAT, Pantnagar with the objectives to assess carbon sequestration potential, G×E interaction studies and pollen tube abnormalities in interspecific crosses of Brassica and verification of interspecific hybrid using chromosome specific markers. Ten mustard varieties were planted in completely randomized block design with three replications under three types of land use system i.e., open field, poplar based agroforestry system and eucalyptus based agroforestry system.The experiment was conducted for two Rabi season 2018-2019 and 2019-2020.To assess G×E interactions and phenotypic stability in Indian mustard varieties AMMI model was deployed.The observations recorded were days to flowering, days to maturity, plant height, Length of main raceme, Number of siliques in main raceme, No. of primary branches/plant, number of secondary branches/plant, Length of a silique, Number of seeds per silique, biological yield/plant, 1000-seed weight, harvest index, seed yield/plant and oil content.For estimating the carbon sequestration potential of different land use system soil organic carbon,tree carbon and crop plant carbon were calculated. For prefertilisation and pollen tube abnormalities interspecific crosses were made among six cultivated species of Brassica, during the Rabi season of 2018-2019. Significant differences for biomass accumulation were observed in all the agroforestry systems. For both the cropping seasons, biomass accumulation was recorded significantly high in eucalyptus based agroforestry system than in poplar based agroforestry system. Total CO2 reduction (tree + crop) followed the same trend as biomass accumulation and was accounted significantly highest by eucalyptus based agroforestry system than poplar based agroforestry system. Among mustard varieties CS 56, followed by RGN 73 had outperformed all other varieties in terms of biomass accumulation and CO2 mitigation across all the three land use system. Soil carbon stocks after two cropping season was recorded significantly higher under eucalyptus based agroforestry system than polar based agroforestry system. Pooled analysis of variances by AMMI model revealed significant differences among the genotypes and also among environments for fourteen agronomic and quality traits studied. G×E interactions were reported to be significant for all the traits studied.Based on AMMI I, AMMI II and ASV estimates, RGN 73 was registered stable across all studied environments with high mean performance for maximum number of traits like days to maturity, plant height, biological yield/plant, harvest index, seed yield/plant and oil content. Favourable environment for maximum number of traits were open field during crop season 2018-2019 and 2019-2020.Poplar based agroforestry system was favourable environment for late flowering, late maturity and biological yield/plant.Eucalyptus based agroforestry system for both crop seasons recognized as most unfavourable environments for maximum traits. RGN 73 was identified as a stable genotype for seed yield and yield related traits along with significantly higher biomass accumulation and CO2 reduction potential. Prefertilisation studies on interspecific crosses revealed several types of pollen tube abnormality like swelling of tip of pollen
tube, coiling of pollen tube, bursting of pollen-tube, more than one tube growing from the single pollen, bending of pollen tube and pollen tubes growing in opposite direction. Molecular validation and characterization of two interspecific hybrids using chromosome specific SSR primers has caused amplification of genome specific band in two interspecific hybrids.The banding pattern for primers in interspecific hybrids was intermediate of banding pattern shown by their parental species. This has suggested that in interspecific hybrids C1 (B.napus × B. juncea) and C2 (B.juncea× B.rapa) certain portion of genome of both the parental species has been transferred.