Inheritance Of Main Traits Related To Yield And Quality, And Their QTL Mapping In Peanut (Arachis Hypogaea L.)

Peanut is one of the most important oil and economic crops in world. Due to cultivated peanut is allotetraploid crop (AABB, 2n = 4x = 40), chromosomes are smaller, vast and complex genome, and the genetic research of peanut cultivar development later, thereby impeding the rapid advance of the peanut industry. Because of the quantitatively-genetic nature of the morphology traits related to yield and quality, relevant research has been slowly. In recent years, with the rapid development of the method for genetic analysis of quantitative traits and molecular biology techniques, in order to explore the inheritance of important traits, QTL mapping of conduct laid a solid foundation.In this study 160 lines were a RILs (Recombination Inbreeding Lines) population extracted from a cross between Zheng 9001 and Zheng 8903, and used to construct a molecular linkage map and analysis quantitative genetic model. With this map the morphology traits related to yield and quality were genetically analyzed, and developed inheritance models and QTL mapping were used to study the above aspects. The main results were described as follows:1. Genetic analysis for important agronomic and quality traits of cultivated peanut which sown in Sanya and Yuanyang was carried out in parents and the RILs. A mixed major gene plus polygene inheritance model was used to perform the genetic analysis of fourteen yield and quality related traits in the RIL population under two environments. The joint segregation analysis in environment I (Sanya, Hainan province) results showed that: For the mainstem height, lateral length and number of mature pods per plant, the best fitting genetic models were polygene model (C); For total branches, number of bearing branches, 100-pod weight, 100-seed weight, kernel percent, protein content, fat content and O/L, all of the best fitting models were two major genes plus polygene (E); For yield per plant, oleic content and linoleic content, the best fitting models were three major genes (F).In environment II (Yuanyang, Henan province) the joint segregation analysis results showed that: For the mainstem height, lateral length, 100-seed weight, protein and fat content, all of the best fitting models were polygene model (C); For total branches, number of mature pods per plant, 100-pod weight, kernel percent, oleic content , linoleic content and O/L, all of the best fitting models were two major genes plus polygene (E); For number of bearing branches per plant, the best fitting model was one major genes (A), For yield per plant, the best fitting model was three major genes (F). At the same time, the genetic parameters of the genetic models for the yield and quality related traits were estimated, the results in two environments showed that the mainstem height, lateral length, number of mature pods per plant and protein content were mainly controlled by polygene, while total branches, number of bearing branches, 100-pod weight, 100-seed weight, kernel percent, yield per plant, fat content, oleic content, linoleic content and O/L were mainly controlled by major genes plus polygene.2. Constructed genetic linkage map of cultivated peanut, total 1556 simple sequence repeat (SSR) markers were used to screen the polymorphism between two parents (Zheng 9001 and Zheng 8903). Among 114 SSR markers with polymorphism, 73 were finally used to construct a genetic linkage map. Based on the RIL population consisting of 160 lines, a genetic linkage map of cultivated peanut genome was constructed, which consist of 16 linkage groups with 73 SSR markers. The map covered 448.28 cM and the longest distance between markers were 27.72 cM.3. QTL localization of agronomic and quality traits, by using composite interval mapping (CIM) and multiple composite interval mapping (MCIM) method, a molecular genetic linkage map structured in this study was adopted to analyze QTL for yield and quality related traits including mainstem height, lateral length, total branches, number of bearing branches, mature pods per plant, 100-pod weight, 100-seed weight, kernel percent, yield per plant, protein content, fat content, oleic content, linoleic content and O/L in cultivated peanut. By using CIM method in environment I (Sanya, Hainan province), 24 QTLs were detected for ten traits and they explained variance range 5.61%~17.98%, while no QTLs were detected for 100-pod weight, 100-seed weight, protein and fat content. By using CIM method in environmentâ…¡(Yuanyang, Henan province), 43 QTLs were detected for twelve traits and they explained variance range 5.03%~31.65%, while no QTLs were detected for 100-seed weight and kernel percent. Based on the genetic map established from the RIL population, the QTLs were detected using the software QTLNetwork version 2.0 with the composite interval mapping of the mixture linear model. QTLs for 14 traits including yield and related agronomic traits and quality traits were analyzed in two environments. A total of 23 additive QTLs and 11 pairs of epistatic effects were detected and distributed on Lg1, Lg2, Lg3, Lg5, Lg6, Lg7, Lg12, Lg13, Lg15 and Lg16, while no QTLs were detected for 100-seed weight. Nine QTLs were detected stable expression in two environments, which were about the mainstem height, lateral length, oleic content, linoleic content and O/L. By using different method, QTLs were performance consistent, which were about the mainstem height, lateral length, total branches, and the number of bearing branches, oleic content, linoleic content and O/L.