| Plant height is a key factor determining the plant type and yield of wheat(Triticum aestivum L.).Reducing plant height appropriately can enhance wheat’s ability to resist lodging,increase harvest index,and achieve high and stable wheat yield.In the early stage,the research group introduced a wild two grain wheat chromosome arm replacement line CASL7 AS with the Israeli common wheat variety Bethlehem(BLH)as the background as the female parent,and created 178 DH lines with Zhejiang A&F12(ZNL12)as the male parent.This study focused on this DH line and conducted multiple point measurements of plant height and yield related agronomic traits over the years.The relationship between plant height and related agronomic traits was explored,and QTL mapping of plant height was performed using 55 K gene chip technology.Candidate genes Rht-B1 b and Rht-D1 b were screened and their genetic effects on plant height were analyzed.The main results are as follows:1.There is a great difference in plant height of DH lines,ranging from 27 cm to 143 cm,with a normal distribution.The plant height of most DH lines ranges from 80 cm to 100 cm,with a significant positive correlation between plant height and ear neck length,1000 grain weight,and each stem node.2.In a field environment of three years and two points,53 QTLs related to plant height were identified,which explained a phenotypic variance of 2.80% to 35.39%.Two stable main QTLs were identified on chromosomes 4B and 4D,which explained 23.77% to 38.75% and 19.96% to 23.61% of the phenotypic variation,respectively,named QPh.zafu.4B-1 and QPh.zafu.4D-1.The physical distance of the QPh.zafu.4D-1 locus located on the 4D chromosome is inconsistent with previous research results,and may be a new QTL locus.3.According to gene annotation,a total of 17 candidate genes were screened within these 2 stable main QTL mapping intervals,including the dwarf genes Rht-B1 b and Rht-D1 b.Fluorescence quantitative identification and analysis using tall and short stem plants showed that the expression levels of Rht-B1 b gene in plants were significantly higher than those in Rht-D1 b gene.4.Clone the Rht-B1 b and Rht-D1 b genes in tall and short DH lines,and perform sequence analysis.It was found that there are regular differences between these two genes in the parents and DH lines: on the 4B and 4D chromosomes,the plant height of the short and tall DH lines shows opposite genetic effects;Through cell biology research,it was found that the length of epidermal cells in the coleoptile of dwarf plants was significantly lower than that of tall plants,suggesting that the variation in wheat plant height may be caused by plant cell elongation. |
