Elucidating the response of the Rht18 gene on the seedling establishment and yield in wheat genotypes (Triticum aestivum L.)
摘要
Wheat is a major commercial cereal crop grown worldwide. The traditionally cultivated wheat varieties carrying Rht-B1b and Rht-D1b (Rht1 and Rht2) are more suited to high-input, stress-free environments but provide limited benefits under less favourable conditions. In the present study, wheat genotypes harboring the alternative semi-dwarf gene Rht18 in the background of HD3086 were evaluated for their effect on seedling establishment and field traits. HD3086 lines carrying Rht-B1b (R1R1), Rht18 (R18R18), both Rht18 and Rht-B1b (R1R1R18R18) and genotypes lacking dwarfing genes (r1r1r18r18) were included. Significant variation was observed in the seedling-stage traits among the different genotype groups (ANOVA, p ≤ 0.05). The coleoptile length of the Rht18-introgressed lines was 20.25% greater than that of HD3086 carrying Rht-B1b. The longer coleoptile length in Rht18 lines was associated with higher shoot length and total dry weight at seedling stage, which positively correlated with grain yield and thousand grain weight under field conditions. Although the Rht18-introgressed genotypes exhibited a 9.8% reduction in plant height compared with HD3086, the introgression of the Rht18 gene did not negatively affect any of the studied yield attributes. Microscopic examination of the peduncle and internode tissues revealed reductions in peduncle cell length (10.95%) and width (8.16%) in Rht18-introgressed lines. The study highlights the potential of diversifying the wheat genetic base through the alternative semi-dwarfing gene Rht18, offering a promising strategy to develop cultivars with improved seedling establishment in the face of a changing climatic scenario.