34 research outputs found
Character association and path analysis in bacterial blight resistance genes pyramided segregating populations of rice (Oryza sativa L.)
No full textAn exploratory research work was conducted to study the character association
and their direct and indirect effects on grain yield in three bacterial
blight resistance genes introgressed segregating populations (F2) in rice.
Data for yield and five other traits which were component of yield were
recorded in 449 F2 individuals in all three crosses. Thousand grain weight
was highly correlated with single plant yield in (r=0.95**, p<0.01) CB 174 R
? IRBB 60> (r=0.48**, p<0.01) CB 87 R ? IRBB 60> (r=0.44**, p<0.01) TNAU CMS
2B ? IRBB 60. Thousand grain weight was exhibited important yield
determining component for CB 174 R ? IRBB 60 (0.92) and CB 87 R ? IRBB 60
(0.45), and panicle length for (0.39) TNAU CMS 2B ? IRBB 60 by direct
effect. The genetic information derived from our study could be useful to
select potential segregating individual among the F2 population for future
rice breeding program.</jats:p
Variability and genetic diversity study in an advanced segregating population of rice with bacterial blight resistance genes introgressed
No full textABSTRACT Bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae is one of the most important widespread disease around the globe and can cause severe yield reductions of up to 30% of the total yield. Genetic variability was studied in 54 families of CB 174 R × IRBB 60 rice with bacterial blight resistance genes introgressed at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore, India. Traits such as plant height and the number of productive tillers per plant were found to have negative skewness in this study, indicating the duplication of gene effects. Panicle length and the number of grains per panicle were found to have positive kurtosis, indicating gene interactions. The phenotypic coefficient of variation was slightly higher than the genotypic coefficient of variation for all traits, indicating that the observed variation was not only due to genotypic but also due to the environmental effect on the expression of these traits. High heritability coupled with high genetic advance as a percent of the mean was observed for plant height. Moreover, moderate heritability coupled with high genetic advance as a percent of the mean was observed for the single plant yield of rice. Cluster and principal component analyses revealed that the 54 F2:3 families were grouped into three clusters based on six agro-morphological traits. Clusters III and II had higher mean values for most of the studied traits than cluster I. Intercrossing lines from distinct clusters can be identified and crossed to generate larger variability to produce desirable recombinants for higher yield with a wide genetic base
Screening for Fertility Restoration Genes linked Marker in Bacterial Blight Resistance Genes introgressed Segregating Population in rice
No full textEffectiveness of selection, parent-offspring correlation and regression in bacterial blight resistance genes introgressed rice segregating population
No full textABSTRACT: 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.</jats:p
Effectiveness of selection, parent-offspring correlation and regression in bacterial blight resistance genes introgressed rice segregating population
No full textABSTRACT: 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
Identification of Bacterial Blight Resistance Genes Introgressed Individuals in the Segregating Population of Rice
No full textRice is the most consumed food crop around the globe. Bacterial blight (BB) caused by Xanthomonas oryzae pv oryzae (Xoo) is the most destructive bacterial disease in rice. The cross CB 87 R × (CB 87 R × IRBB 60) was screened for three BB resistance genes Xa21, xa13 and xa5 with the help of molecular markers revealed 15 individuals found to have resistance genes. The identified individuals with Rf gene were considered as an important criterion in the high yielding background, and the stabilized individuals could be used as genetic stocks for disease resistance breeding program in rice
Variability and genetic diversity study in an advanced segregating population of rice with bacterial blight resistance genes introgressed
No full textABSTRACT Bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae is one of the most important widespread disease around the globe and can cause severe yield reductions of up to 30% of the total yield. Genetic variability was studied in 54 families of CB 174 R × IRBB 60 rice with bacterial blight resistance genes introgressed at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore, India. Traits such as plant height and the number of productive tillers per plant were found to have negative skewness in this study, indicating the duplication of gene effects. Panicle length and the number of grains per panicle were found to have positive kurtosis, indicating gene interactions. The phenotypic coefficient of variation was slightly higher than the genotypic coefficient of variation for all traits, indicating that the observed variation was not only due to genotypic but also due to the environmental effect on the expression of these traits. High heritability coupled with high genetic advance as a percent of the mean was observed for plant height. Moreover, moderate heritability coupled with high genetic advance as a percent of the mean was observed for the single plant yield of rice. Cluster and principal component analyses revealed that the 54 F2:3 families were grouped into three clusters based on six agro-morphological traits. Clusters III and II had higher mean values for most of the studied traits than cluster I. Intercrossing lines from distinct clusters can be identified and crossed to generate larger variability to produce desirable recombinants for higher yield with a wide genetic base.</div
Introgression of Bacterial Blight Resistance Genes (Xa21, xa13 and xa5) into CB 174 R, an Elite Restorer Line in Rice
No full textBacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the major diseases causing a severe yield reduction in rice-growing regions. One dominant (Xa21) and two recessive genes (xa13 and xa5) were introgressed into CB 174 R through marker-assisted breeding. The present study found three (Xa21 + xa13 + xa5) and two (Xa21 + xa13 or Xa21 + xa5 or xa5 + xa13) gene-introgressed combinations in the early segregated materials through foreground selection. The identified homozygous/heterozygous individuals were forwarded to the next cycles of breeding to fix homozygous conditions for all three genes with an improved agronomic performance background and, thus, could be used as a donor source for a future rice breeding program
Genetic Variability for Yield and Yield Components Characters in Bacterial Blight and Blast Resistance Genes Introgressed Backcross Populations in Rice
No full text
