Genetic basis of lineage-specific evolution of fruit traits in hexaploid persimmon

Frequent polyploidization events in plants have led to the establishment of many lineage-specific traits representing each species. Little is known about the genetic bases for these specific traits in polyploids, presumably due to plant genomic complexity and their difficulties in applying genetic approaches. Hexaploid Oriental persimmon (Diospyros kaki) has evolved specific fruit characteristics, including wide variations in fruit shapes and astringency. In this study, using whole-genome diploidized/quantitative genotypes from ddRAD-Seq data of 173 persimmon cultivars, we examined their population structures and potential correlations between their structural transitions and variations in nine fruit traits. The population structures of persimmon cultivars were highly randomized and not substantially correlated with the representative fruit traits focused on in this study, except for fruit astringency. With genome-wide association analytic tools considering polyploid alleles, we identified the loci associated with the nine fruit traits; we mainly focused on fruit-shape variations, which have been numerically characterized by principal component analysis of elliptic Fourier descriptors. The genomic regions that putatively underwent selective sweep exhibited no overlap with the loci associated with these persimmon-specific fruit traits. These insights will contribute to understanding the genetic mechanisms by which fruit traits are independently established, possibly due to polyploidization events

European, Chinese and Japanese pear fruits exhibit differential softening characteristics during ripening

Softening characteristics were investigated in three types of pear fruit, namely, European pear ‘La France’, Chinese pear ‘Yali’, and Japanese pear ‘Nijisseiki’. ‘La France ’ fruit softened dramatically and developed a melting texture during ripening, while ‘Yali ’ fruit with and without propylene treatment showed no change in flesh firmness and texture during ripening. Non-treated ‘Nijisseiki’ did not show a detectable decrease in flesh firmness, whereas continuous propylene treatment caused a gradual decrease in firmness resulting in a mealy texture. In ‘La France’, the analysis of cell wall polysaccharides revealed distinct solubilization and depolymerization of pectin and hemicellulose during fruit softening. In ‘Nijisseiki’, propylene treatment led to th

A Two-year Longitudinal Study on the Periodontal Health Educationfor Junior High School Students using the Oral Rating Index

中学生における歯周状態の変化を把握するために広島市内の中学生を対象として経年的に調査した。検診後には歯周保健指導を行い,歯周状態の変化について検討した。対象は1998年度に1年次であった生徒, 116名(男子59名,女子57名)であった。歯周状態の評価は, Oral Rating lndex (0RI)を用いた。検診後は生徒自身のORI値による評価を知らせ,歯周病に関するプリント「保健室便り」を配布した。1. 3年次を除き0町の平均値に性差が認められ,女子の方が男子よりも歯周状態は良好であった(1年次:p<0.05,2 年次:p<0.0l)。2. 男子では学年が上がるにしたがってORIの平均値が上昇した(p<0.05)。女子においては3年次でORIの平均値が減少したが, 1年次から2年次にかけてORIの平均値が上昇した(p<0.0l)。3. 男子は学年が上がるにしたがって歯周状態が不良を示す一1の割合が減少した。女子においてー1あるいは-2を占める割合が減少した。以上より,経年的調査においてORIによる歯周状態の評価とプリント形式で配布される「保健室便りJを活用した歯周保健指導が生徒の口腔衛生意識向上の一助になると思われた。The purpose of this study was to assess the gingival health and oral hygiene status in junior highschool students and to compare the effectiveness of periodontal education. A two-year longitudinalsurvey was conducted for 116 school students from 1998 to 2000 in Hiroshima, Japan. The Oral RatingIndex (ORl) was used for assessing periodontal status and hislher result was given to each student.A brochure has been provided since 1995, following completion of the fIrst survey. The meanORl score of females was signifIcantly higher than that of males at each grade level, except the thirdgrade in 2000. The mean ORl score of males from 1998 to 2000 signifIcantly increased (p<0.05).There were no signifIcant differences in the mean ORI score of females from 1998 to 1999 signifIcantlyincreased (p<0.01).In conclusion, the results of the present study indicate that an informational brochure on periodon-/tal diseases could be helpful to improve the periodontal condition of junior high school students