Inheritance and Molecular Mapping of Tight-placenta Gene and Seed Traits in Chinese Hami Melon ‘Queen’

Abstract

<jats:p>Hami melon ‘Queen’ (<jats:italic>Cucumis melo</jats:italic> ssp. <jats:italic>melo</jats:italic> var. <jats:italic>ameri</jats:italic> Pangalo) is the most widely cultivated and exported type of melon in Xinjiang Province, Northwest China. We previously found the unique traits of Hami melon ‘Queen’ for <jats:italic>wave seeds</jats:italic> and <jats:italic>tight-placenta</jats:italic> fruits. An analysis of the inheritance showed that these traits were controlled by two recessive genes <jats:italic>wave seed</jats:italic> (<jats:italic>ws</jats:italic>) gene and <jats:italic>tight-placenta</jats:italic> (<jats:italic>tp</jats:italic>) gene, respectively. Here, to identify these two traits and melon seed–related traits, segregation populations including BC<jats:sub>1</jats:sub> and F<jats:sub>2</jats:sub> derived from a cross between ‘Queen’ (P<jats:sub>1</jats:sub>) and MR-1 (P<jats:sub>2</jats:sub>) were used as mapping populations. Eighty-seven simple sequence repeat (SSR) markers were used in map construction of BC<jats:sub>1</jats:sub>P<jats:sub>1</jats:sub> population, and as a result, <jats:italic>ws</jats:italic> and <jats:italic>tp</jats:italic> were identified on linkage group 1. Analysis of quantitative trait locus (QTL) referring seed traits showed that QTL <jats:italic>ss1.1</jats:italic> for seed shape (SS) and QTL <jats:italic>sl1.1</jats:italic> for seed length (SL) were located at LG 1, supported by likelihood of odds (LODs) of 15.6 and 13.4, respectively, and both linked with <jats:italic>ws</jats:italic>. Subsequently, the genetic linkage and parental re-sequence analysis were constructed for fine mapping <jats:italic>ws</jats:italic> and <jats:italic>tp</jats:italic>. Genetic analysis showed that <jats:italic>ws</jats:italic> and <jats:italic>tp</jats:italic> were located in CM3.5_scaffold00060 on LG 1, flanked by InDelchr1-3241 and InDelchr1-3233. The 80.9-kb physical distance of this region included 11 candidate genes. Among them, MELO3C023549 and MELO3C023551 could be candidates for <jats:italic>ws</jats:italic> and <jats:italic>tp</jats:italic> by sequence alignment and allelic variation survey in parental lines. MELO3C023549 was predicted to encode an MYB46-like transcription factor related to positive regulation of secondary cell wall biogenesis. MELO3C023551 was annotated to encode a cellulose synthase A (CESA) associated with cellulose biosynthetic process.</jats:p>

Quantitative Trait Loci for Seed Size Variation in Cucurbits – A Review

“…The 2 QTL (SL5.1 and SD5.1) on Chr5 (PVE = 9.9-11.2%), and 2 QTL (SL1.1 and TGW1.2) on Chr1 were validated. In addition, using a BC 1 population, Ning et al (2018) also detected QTL for SL and 100SWT on Chr1 (LG1), but not in the same region reported by Ye et al (2017). With a high-density genetic linkage map constructed by a RIL population, Pereira et al (2018) identified 4 QTL for SWD with 1 major QTL (SWQU8.1) located on Chr8 FIGURE 5 | Syntenic relationships of watermelon chromosomes W2, W6, and W8 harboring major-effect consensus SS QTL with cucumber, melon and pumpkin chromosomes.…”