TY - BOOK AU - Devika R AU - Sreekumar S G (Guide) TI - Genetic analysis of Bacterial Blight (Xanthomonas Oryzae pv. Oryzae Ishiyama) Resistance and Yield in Rice (Oryza sativa L.) U1 - 630.28 PY - 2002/// CY - Vellayani PB - Department of Plant Breeding and Genetics, College of Agriculture N2 - Bacterial blight disease caused by Xanthomonas oryzae pv. oryzae Ishiyama is a major constraint limiting rice production in Kerala especially in Kuttanad, the rice bowl of Kerala. Keeping in view the limited success achieved in controlling the disease with conventional chemicals, the present investigation entitled "Genetic analysis of bacterial blight (Xanthomonas oryzae pv. oryzae Ishiyama) resistance and yield in rice (Oryza sativa L.)" was carried out at Rice Research Station, Moncompu for the genetic analysis of bacterial blight resistance and yield in rice for developing high yielding disease resistant varieties through the estimation of genetic variability in a collection of germplasm, screening and identification of resistant donors, estimation of combining ability and gene action by line x tester analysis and the estimation of the gene action involved in the inheritance of bacterial blight resistance and yield by generation mean analysis. One hundred and fifty genotypes collected from various sources VIZ., International Rice Research Institute, Philippines, Directorate of Rice Research, Hyderabad, different Rice Research Stations of Kerala Agricultural University and local varieties of rice cultivated in Kuttanad, Palakkad and Wyanad were evaluated in the field adopting a randomised block design with two replications at Rice Research Station, Moncompu .. 2 in additional crop of 1998. Simultaneously 150 genotypes were evaluated in pots in CRD with 2 replications for artificial screening of bacterial blight by clip inoculation technique. Analysis of variance of the data revealed highly significant difference for all the 12 characters viz; days to 50 per cent flowering, plant height, total number of tillers hirl", number of productive tillers hill-I, flag leaf area, 1000 grain weight, length of panicle, number of fully filled grains panicle-I, grain yield plant! , straw yield plant", incidence ot bacterial b\\gnt uisease a1\u sheath b\\%\\t \l\c\uem:e \l\U\c:a.\\ws \\\~ presence of high variability. The pathogen was identified as Pathotype I based on the resistant reaction on DV 85 and susceptible reaction on IR8, IR20, Kogyoku, Malagkit Sung song and Rantai Emas. All the characters except total number of tillers hill-1 and flag leaf area recorded high estimates of GCV indicating the presence of greater genetic variability and better scope for the genetic improvement of these characters by means of selection. High heritability estimates along with moderate to high GA recorded for days to 50 per cent flowering, number of productive tillers hill-I, length of panicle, grain yield plane 1 and percentage of bacterial blight disease incidence suggests that the above characters are under the control of additive gene action. Therefore, the above characters may be considered during selection programme for the improvement of yield and bacterial blight resistance. Six high yielding locally adapted varieties and three bacterial blight resistant donors were selected from the evaluation of germplasm 3 (Experiment 1) and crossed in a Line x tester fashion during Puncha 98- 99 at Rice Research Station, Moncompu and 18 LxT combinations were developed. The six lines, 3 testers and 18 LxT combinations were evaluated in an RBD with 3 replications during the additional crop season of 1999. Data on eleven traits collected from field experiment were subjected to L x T analysis for estimating combining ability. Simultaneously the six selected lines, 3 testers and their 18 LxT combinations were raised in pots in CRD with 3 replications for artificial inoculation and screening of BB and percentage incidence of BB was recorded based on standard evaluation system for rice (IRRI, 1980) and subjected to statistical analysis. Analysis of variance revealed significant difference among parents and crosses. On further analysis there was significant difference among lines also. Based on the mean performance and gca effects for grain yield and yield attributing characters Uma and Aruna among the lines were the best genotypes. With regard to 50 per cent flowering, plant height etc. Jyothy among the lines was found to be the best. For bacterial blight resistance, the testers viz., BJ1 and DV 85 were found to be the best genotypes. Based on the mean performance and sea effects, the crosses Aruna x BJ 1, Uma x DV 85 and Jyothy x DV 85 were identified as the best specific combiners. These hybrids showed negative sca effect with respect to days to 50 per cent flowering, plant height and percentage of bacterial blight disease, where as positive sca effect was recorded for almost all the yield and yield attributing characters. Hence the above three cross combinations may be carried forward by pedigree selection 4 for identifying and selecting desirable recombinants with high yield along with bacterial blight resistance. The three superior crosses identified from the evaluation of Line x tester crosses were utilized for generation mean analysis. The three selected F 1 S and their respective parents were planted in a crossing block during Puncha 99-2000 at Rice Research Station, Moncompu. Six generations PI' P 2' F l' F 2' Bland B2 developed in the three selected cross combinations were evaluated in an RBD with 3 replications during the additional crop season of 2000 at Rice Research Station, Moncompu. All the six generations of 3 crosses were raised in pots for artificial inoculation and screening against bacterial blight disease incidence. From generation mean analysis of six generations, the additive, dominance and epistatic gene actions were estimated for 11 traits. In all the three crosses, significance of scaling tests revealed the presence of non allelic interaction for the ten characters studied. None of the scales was significant for the number of productive tillers hill-1 in Aruna x BJI and Jyothy x DV 85 indicating the absence of epistasis. In Uma x DV 85 significance of scale D indicates additive x additive (i) type of gene action. For plant height only the additive effect (d) was found to be negative and significant in all the three crosses indicating the posibility of developing dwarf types by simple selection. The magnitude of dominance (h) and additive x additive (i) type of interaction were greater than other types of gene action for most of 5 the yield components in all the three crosses and hence recurrent selection is suggested for the improvement. For percentage of bacterial blight disease incidence the magnitude of dominance and dominance x dominance (1) interaction was greater than additive gene action for all the 3 crosses. Hence combination breeding is advocated for the improvement. Utilizing the genetic components, magnitude of heterosis were estimated for eleven characters in all the th~ee crosses. Days to 50 per cent flowering and percentage of bacterial blight disease incidence registered a significant negative heterotic effect for all the three crosses suggesting the possibility of developing early flowering and disease tolerant varieties. In Uma x DV 85, flag leaf area and number of fully filled grains panicle"! recorded significant positive heterotic effect which can be utilized for developing high yielding varieties. Estimates' of transgressive segregants In F 2 for 11 characters revealed transgressive segregation on both directions in all crosses indicating the possibility of identifying desirable recombinants which can be further utilized for developing superior varieties. It can be concluded that three superior crosses viz., Aruna x ,BJ 1, Uma x DV 85 and Jyothy x DV 85 identified in this study may be carried forward by pedigree method for developing high yielding, bacterial blight disease resistant varieties. UR - http://krishikosh.egranth.ac.in/handle/1/5810015068 ER -