ABSTRACT
ABSTRACT: The effectiveness of early generation selection was practiced in bacterial blight resistance genes introgressed F2 and F2:3 population of the cross CB 174 R × IRBB 60 in rice. F2 Selection have been proved to be robust and effective tool in crop improvement program. Selection differential was positive for all studied traits. Selection response was high for number of grains, thus indicating the effectiveness of selection for these character. Realized heritability was found high for number of grains and thousand grain weight, suggested that direct selection was effective. Expected selection response and predicted genetic gain was high for number of grains. Parent-offspring correlation showed low but significance association for number of productive tillers (r=0.47**, P<0.01), single plant yield (r=0.35**, P<0.01) and (r=0.30*, P<0.05) panicle length in F2 and F2:3 generation indicates that selection was fruitful in early generation. Statistically regression coefficient was not significant linear dependence of the mean of F2 and F2:3 generation.
RESUMO: A eficácia da selecção das primeiras gerações foi praticada na população F2 e F2: 3 de CB 174 R × IRBB 60 do gene bacteriano. A seleção foi positiva para todos os caracteres estudados. A resposta de seleção foi alta para o número de grãos. A herdabilidade realizada foi encontrada alta para o número de grãos e mil grãos de peso, sugeriu que a seleção direta foi eficaz. A resposta à seleção esperada e o ganho genético previsto foi elevado para o número de grãos. A correlação entre pais e filhos mostrou forte associação com o número de latifundiários produtivos (r = 0,47**, P<0,01), produção única de planta (r = 0,35**, P<0,01) e (r = 0,30*, P<0,05) Comprimento em F2 e F2:3 geração indica que a seleção foi frutífera. O coeficiente de regressão estatística não foi dependência linear significativa da média de F2 e F2:3 geração.
ABSTRACT
[ Objective ] To assess the resistance risk of Culex pipiens pallens to pyriproxyfen in Culexpipiens pallens, to predict the rate of resistance development and to provide the reference for scientific and rational application of insecticides. [ Methods ] The resistance strain was developed by group selection, and the realized heritability ( h2 ) of Culex pipiens pallens resistance to deltamethrin was estimated by Tabashnik's method. [ Results] The resistance of Culex pipiens pallens to pyriproxyfen had increased by 5.69-fold after 12 generations of indoor breeding, and the h2 of Culex pipiens pallens to pyriproxyfen was 0.02, indicating that a relatively risk of resistance development. [ Conclusion] The results indicate that Culex pipiens pallens has resistance risk to pyriproxyfen, so the application of the insecticide must be scientific and rational.