The present investigation was carried out at Rice Research and TrainingCenter and lab of Plant Protection Institute, Sakha, Kafr EL-Sheikh, Egypt, during 2011 and 2012 seasons. The objectives of this investigation is amid to study the genetic behavior of ten rice genotypes under three sowing dates (May1^st, May 15^th and May30^th), the effect of different sowing dates on grain quality characters, and on the infestation by stem borer and to evaluate the susceptibility of certain rice varieties against the infestation by Lesser grain borer, Rhizopertha dominica (F.).The tested genotypes were; Giza177, Giza 178, Sakha 101, Giza 182, GZ 9057-6-1-3-2, GZ 9577-4-1-1, GZ 9523-2-1-1-1, GZ 9461-4-2-3-1, Egyptian Yasmin, and SK2034 H1. Giza 178 cultivar produced maximum grain yield and it remained statistically at par with SK2034 genotype. Egyptian Yasmin gave minimum grain yield. Grain yield averaged across all the genotypes seems to be maximum at sowing date of 1^st May. However, the lowest yield was recorded in sowing date of 30^th May. Sowing dates significantly affected the milled rice % in the first season only and highest milled rice % belonged to the second planting date in the first season. Highest milled rice % were obtained for Giza 177 and GZ 9523-2-1-1-1; the lowest percentages were observed for GZ 9577-4-1-1 and Giza 178. For Stem borer (Chilo agamemnon Bles.), Giza 178, Sakha101, GZ 9577-4-1-1 and GZ 9461-4-2-3-1 were resistant (R) with 1.44, 0.83, 2.66 and 1.93 WH%, respectively. While, five genotypes (Giza177, Giza182, GZ 9057, GZ 9577-4-1-1 and SK2034 H1) were  moderately resistant (MR) with 4.18, 4.14, 5.94, 3.46, and 5.36 WH%, respectively. On the other hand, one genotype (Egyptian Yasmin) was moderately susceptible (MS) with 6.32 WH%. The number of adult emergence of Rhizopertha  dominica ranged from 1.08 insects (Sakha101) to 8.25 insects (GZ9577-4-1-1) (low susceptibility varieties to insect infestation). Also, the number of adult emergence ranged from 13.08 insects (Giza182) to 17.58 insects (Giza177) for moderate susceptibility varieties to insect infestation. Also, the number of adult emergence ranged from 21.08 insects (Egyptian Yasmin) to 22.58 insects (GZ 9057-6-1-3-2) which proved to be high susceptibility varieties to insect infestation. Clustering analysis for varieties, based on similarity of quantitative characters, produced two large distinct groups. The first one included five rice genotypes; Giza 178, Giza 182, GZ 9523-2-1-1-1, Egyptian Yasmin and SK2034 H1. These genotypes were Indica and Indica-Japonica types except Gz 9523-2-1-1-1 was Japonica type. While, the second group included  Giza 177, Sakha 101, GZ 9057-6-1-3-2, GZ 9577-4-1-1 and GZ 9461-4-2-3-1, these genotypes were Japonica types and similar in duration and grain yield characters.