In rice, the characteristic of low glutelin is controlled by a dominant gene, Lgc1. There have been few studies that investigated the influence of Lgc1, except in terms of seed storage protein composition. Additionally, the effects of this gene on taste and processing characteristics have not been clarified. To investigate specific gene pleiotropy, it is effective to compare isogenic lines with a common genetic background. In this study, co-dominant DNA markers for PCR were developed for the breeding of isogenic lines. Two near-isogenic line pairs were successfully developed with these DNA markers. Furthermore, to investigate the influence of Lgc1, basic agronomic characteristics of these near-isogenic line pairs were examined. Between near-isogenic lines with different protein compositions, the low-glutelin type was significantly heavier in terms of 1000-kernel weight of brown rice than its wild type. The low-glutelin type was also superior to its wild type in terms of the quality of appearance of brown rice. However, notable differences were not shown in days to heading, days to ripening, culm length, panicle length, grain yield, shape of brown rice, and protein content of brown rice. From these results, it was concluded that the two sets of near-isogenic line pairs developed in this study should be useful for investigation of the pleiotropism of the Lgc1 gene.

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QTL analysis was performed using an F₁ population derived from a cross between tochiotome and itigotyukanbohonnou2gou (Nou2gou) in order to identify a resistance-related region of the genome of Glomerella cingulata. We used a pseudo-testcross strategy in combination with DNA markers (RAPD, AFLP, SSR) that were segregated 1:1 in F₁ populations. The tochiotome map comprised 376 markers distributed among 30 segregation groups (full length, 1005.4 cM). The Nou2gou map comprised 506 markers distributed among 29 segregation groups (full length, 1448.1 cM). As a result of QTL analysis, nine resistance-related regions were detected and mapped among the parent cultivars. In addition, the segregation ratio of markers and groups linked in the repulsion phase analysis suggests that octoploid strawberry cultivars are allopolyploid and display disomic segregation.

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