| In this study,a large F1,F2 and F2:3 population was generated from a cross between the maternal Z571 and paternal CCRI 49 lines.Study on the physiological and biochemical mechanism between plant type and hormone,correlation analysis between plant type and yield and quality.Clear different varieties between spatial and temporal variations of hormone and the impact between the yield and quality of plant morphological traits.Construction of a high-density genetic map using genotyping by sequencing(GBS)for quantitative trait loci(QTL)analysis of plant morphological traits in upland cotton(Gossypium hirsutum L.).Our study provides an efficient approach for fast detection of QTL underlying complex trait variation with high accuracy,thus providing preliminary information that can improve the efficiency of subsequent machine cotton picking through breeding and molecular marker-assisted selection methods.The main results were as follows:1)Plant hormone regulating mechanism of plant type.After flourishing budding date to multi-topping period,middle leaves indoleacetic acid(IAA)content declined sharply,zeatin(ZA)content increased,ZA/IAA content ratio low induced lateral bud differentiation,promoting CCRI49 vegetative shoot numbers increase;Gibberellic acid(GA3)content in the under leaves each period are low,inhibiting the growth of first fruiting branches node of CCRI 49;To the early flowering period before topping,in the middle and under leaves abscisic acid(ABA)content,GA3/ABA content high,inhibiting CCRI 49 main stem and first fruiting branches node elongation growth.2)Plant morphological traits and yield and quality correlation analysis.There was a significant separation between the agronomic traits of F2:3 population lines,and many ultra Pro individuals appeared in their descendants.When selecting in the field,we should pay attention to the complex relationship among agronomic traits.Yield per hectare was significantly positively correlated with plant height and number of fruit branches.Number of fruit branches was significantly negatively correlated with the average length of fiber and fracture specific strength,while significantly positively correlated with the value of the micronaire.Number of vegetative branches were significantly positively correlated with the average length of fiber and fracture specific strength,while significantly negative correlated with the value of the micronaire.The boll number,one component factor of yield,was significantly positively correlated,with the average length of fiber and fracture specific strength,while significantiy negatively correlated with the value of the micronaire.The boll weight,another component factor of yield,showed a converse agronomic traits' correlation with boll number.3)Construction of the genetic map.A total of 29263 candidate markers were finally obtained after filtering the markers with complete coverage during genotyping.Using a chi-squared test,the 12853 candidate markers were separated and filtered at a threshold P-value of 0.001.After a partial separation analysis,5,886 of the available markers were finally identified.Screening these data with a Perl script yielded 5,571 SNPs with 3,187 Bin markers,were distributed in the 26 linkage groups,the same as the haploid chromosome number.The genetic map spanned 3,828.551 c M in length,with an average distance between markers of 0.687 c M.4)QTL mapping of plant morphological traits.QTL were mapped using Win QTL composite interval mapping(CIM)in the software of F2 and F2:3 two years single environment plant-type traits respectively for QTL mapping.Seventeen QTL in total were identified: seven QTL for PH on Chr5 and Chr25,and explained 7.91–18.76% of the observed phenotypic variation;eight QTL for HFFBN on Chr03,Chr04,Chr7,Chr09,and Chr23,which explained 2.20,7.97,9.15,5.59,3.84,9.64,6.90 and 7.79% of the observed phenotypic variation;and two for NOVS on Chr17 and Chr19,explaining 0.33% and 0.66% of phenotypic variation,respectively. |
PDF Full Text Request