A method for the synthesis of allyl substituted γ-butenolides via carbonyl ylide rearrangement of vinyl sulfoxonium ylide-derived carbenes has been developed. At rt, the mechanism involves a carbonyl ylide generation/allyloxy furan formation/[3,3]-sigmatropic rearrangement/isomerization sequence for the generation of 3-allyl butenolides. At 70 °C, instead of the final isomerization step, the resulting [3,3]-sigmatropic rearrangement product undergoes further [3,3]-sigmatropic rearrangement to produce 5-allyl butenolide. In the absence of the catalyst, the reaction affords a diene via [2,3]-sigmatropic rearrangement.

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India, the second most populated country and the largest wheat producer worldwide, is vulnerable to global warming especially heat stress. In the present investigation, the doubled haploid population derived from PBW343/IC252478 cross was characterized for various phenotypic and morpho-physiological traits and subjected to stability analysis under heat stress conditions. These lines were planted on a single location i.e., Agricultural farm of Rajendra Prasad Central Agricultural University, India for two successive seasons 2017/2018 and, 2018/2019 under three different sowing dates (Controlled or timely, late and, very late sown conditions). Here, the location preferred for this study was because it represents a hotspot for wheat production and the major constraint for the wheat grower is inclining heat stress. The alpha lattice design was used for the current investigation with three replicates. The overall objective of this study was to identify the ideal double haploid lines for heat-stressed conditions. The results revealed that heat stress had a significant adverse impact on all considered traits contributed to overall yield losses of about 50%. Stability measurements, and genotype × environment interaction (GGE), were useful tools to determine the ideal lines for late sowing (heat stressed condition) and very late sowing condition (terminal heat stress). Therefore, in the ranking of genotypes for both mean yield and stability performance across the six environments, DH 71, DH 150, DH 64, DH 138, DH 98, DH 84, DH 62, DH 104, DH 74, DH 3, DH 104, DH 107 & DH 156 were ranked closest to ideal genotype, these were highly adapted, most stable, heat tolerant and high yielding lines indicating them as the most desirable genotypes out of 167 lines studied. Hence, the physiological traits SPAD index (Soil plant analysis development) and Canopy temperature (CT) can be used effectively to screen out the line for heat tolerance. In addition, the stable wheat genotypes identified could be used in the future wheat breeding programs.

Considering global warming as a major constraint of yield and quality, the present study accessed the impact of terminal heat stress on wheat yield stability and grain Fe and Zn content in wheat. Twenty-three wheat genotypes of CGIAR Research Program (CRP) and two check varieties, PBW343 and HD2967 were evaluated for grain yield stability and the Fe and Zn content under heat stress conditions at terminal stage. Stability measures indicated CRP7, CRP8, CRP33, CRP46, and CRP48 to be the most stable genotypes. Grain iron (Fe) and zinc (Zn) content showed a high degree of variation. Under normal sown conditions the Fe content varied from 20.47 ppm (HD2967) to 76.07 ppm (CRP7) while the Zn content varied from 25.17 ppm (HD2967) to 65.6 ppm (CRP48). Under the stress, variation in the Fe content was observed from 10.17 ppm (PBW343) to 43.93 ppm (CRP54) whereas the Zn content variation ranged from 20.33 ppm (CRP30) to 55.13 ppm (CRP48). The overall average content of Fe was reduced by 31.98 % and Zn by 5.91% under the heat stress indicating grain Fe content to be highly vulnerable to the terminal heat stress than the Zn content.