Variation in grain filling and dry matter partitioning in synthetic derived wheat (Triticum aestivum L.) introgression lines under heat stress
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Date
2023
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Punjab Agricultural University
Abstract
Wheat crop has specific temperature requirements and a shift in sowing dates impose temperature stress at different crop growth stages. The present study was conducted on introgression lines derived from two synthetic hexaploid wheats (SHW14102 and SHW3761) and two hexaploid bread wheats (BWL4444 and BWL3531) with an aim to identify heat tolerant lines. The SHW14102 was crossed with two bread wheat lines BWL4444 and BWL3531, while SHW3761 was crossed with BWL4444, to develop BC1F1s. About 100 BC1F1 seeds from each cross were developed into doubled haploids (DH). These lines were assessed for phenological, physiological and yield traits under both early and late sown conditions. Based on the results of genetic variability analysis, 100 doubled haploids out of 390 population were selected for further multivariate analysis. These 100 DH were screened for yield traits by principal component analysis (PCA) and differentiated into three clusters by hierarchical clustering. Cluster 1 had maximum value for grain yield, biomass and thousand grain weight under both early and terminal heat stress conditions, thus, suggesting these as a potential germplasm to withstand heat stress. Source-sink manipulation was done in order to study the dry matter partitioning in high grain weight introgression lines. Grain yield per plant was reduced by 9.2% in sink manipulation (spikelets removal) while in source manipulation (flag leaf removal) this caused the reduction in plant yield by 1.95%. Thus, source was not a limiting factor for grain yield in introgression lines, whereas sink appeared to be a limiting factor. Further, these 15 high grain weight introgression lines were evaluated on the basis of biochemical attributes viz., water soluble sugars, proline content, malondialdehyde (MDA) content, hydrogen peroxide content and α-amylase activity under three different sowing regimes i.e., early, timely and late. The results showed that the doubled haploids that outperformed on the basis of both agronomic and biochemical attributes were DH3, DH12, DH30, DH31, DH41, DH45 and DH121. These lines could be considered as a potential candidate for utilizing in future breeding programmes aimed at early and terminal heat stress tolerance.
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Tavisha Singh (2023). Variation in grain filling and dry matter partitioning in synthetic derived wheat (Triticum aestivum L.) introgression lines under heat stress (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.