Genetic analysis and molecular markers associated with multi-gynoecia (Mg) gene in Trigrain whea

Abstract

Trigrain wheat normally produces up to three gynoecia in a single floret and forms three close-set grains. The gene conferring the multi grain phenotype was earlier designated Mg, the multiple gynoecia gene. Different genetic patterns controlling this trait have been reported. In the present work we studied the inheritance of the three grains trait and identified simple sequence repeats (SSR) markers linked to the Mg gene. Segregation analysis in the cross IGDB-TW (trigrain wheat)/Chinese Spring confirmed that a single dominant gene controlled the three grains trait. An allelism test showed that the same gene controlled the trigrain trait in line Trigrain-Yin 1. A total of 339 microsatellite markers were tested for polymorphism by bulked segregation analysis (BSA) in an F2 population. Six microsatellite markers, Xcfd233, Xgdm6, Xgdm87, Xgwm311, Xgwm349 and Xgwm539, on chromosome 2DL, were linked to Mg. Using the CS 2D deletion lines, Mg gene was localized to the distal region of chromosome 2DL. The microsatellite markers identified in this study have the potential for further mapping and map-based cloning of the gene.Key words: Simple sequence repeats, physical mapping, trigrain wheat

Genetic mapping and expressivity of a wheat multi-pistil gene in mutant 12TP

“…However, the gene 12TP showed a dosage effect, indicating that a semi-dominant gene rather than a dominant gene. This result differs from all previously described wheat multi-pistil mutants reported before, including Pis1 and Mg (Peng et al 2008;Wang et al 2009). Our results indicated that 12TP is a novel multi-pistil gene.…”

“…There were two multi-pistil genes, Pis1 and Mg, have been previously located on 2DL. Both Pis1 and Mg were in the middle region of the SSR markers Xgwm539 and Xgwm349 (Peng et al 2008;Wang et al 2009). Yang et al (2017) constructed a high-density linkage map of wheat using GBS-SNP data, and found that the Pis1 was located in a 4.1-cM region flanked by the SNP markers M70 and M71.…”

“…There may be as many as 11 florets in each spikelet (Sibony and Pinthus 1988), and increasing the number of grains developed per spike is vital for maximizing yield potential. Previous Tong 1984;Shen et al 1992), or by a single dominant gene (Chen et al 1983;Peng et al 2003;Ma et al 2006;Wang et al 2009). Differences in cytoplasms (Wu et al 2000) or the presence of foreign cytoplasms (e.g., that of Aegilops kotschyi or Aegilops ventricosa), have been additionally shown to inhibit the expression of some 'tri-grain' genes (Ma et al 2000).…”

“…Differences in cytoplasms (Wu et al 2000) or the presence of foreign cytoplasms (e.g., that of Aegilops kotschyi or Aegilops ventricosa), have been additionally shown to inhibit the expression of some 'tri-grain' genes (Ma et al 2000). The multi-pistil genes are located on 2DL, 5DS, 6BS and 6B (Tong and Tong 1984;Shen et al 1992;Ma et al 2000;Peng et al 2008;Wang et al 2009;Yang et al 2017). Map-based cloning, which requires finding closely linked markers, is the most effective method for the cloning of multipistil genes.…”

“…reports have described three pistil (TP) mutants, in which spike morphology is normal but two additional pistils initiate after emergence of the first one, resulting in three pistils developing per floret (Chen et al 1983;Tong and Tong 1984;Peng 2003;Wang et al 2009). As a result, three seeds can be cultivated per floret, increasing the number of grains per spike (Yang et al 2017).…”