Estimation of combining ability and heterosis for drought tolerance in upland rice (Oryza sativa l.)
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Date
2014
Authors
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Publisher
JNKVV
Abstract
Abstract
The present investigation entitled “Estimation of combining ability and heterosis for drought tolerance and in upland rice (Oryza sativa L.)” was undertaken to determine the extent of variability, to assess the GCA effects of parents and SCA effects of crosses, to ascertain the magnitude of exploitable heterosis, to study type of gene action involved for yield, grain quality and other related characters and to study correlations and path coefficients.
The experimental material consisted of seven lines viz., REWA-1103-IR, IET-22107, IR-79971-REWA-51, IR-82635-47-1, OM-7938, IR-82639-115-1, IR-826310-67-2 and three testers viz., IR-84898-B-168-39, CRR-451-193-3-B, DANTESWARI and twenty one hybrids were generated in line x testers pattern. The parents and hybrids were raised in a randomized block design with three replications during kharif 2011 at the Research Farm, College of Agriculture Rewa, JNKVV, Jabalpur, (M.P.) India.
Observations were recorded for days to 50 per cent flowering, plant height, number tillers per plant, number of panicles per plant, number of grains per panicle, test weight, panicle length, grain yield per plant, biological yield per plant, harvest index.
Analysis of variance revealed that variance due to the line x tester was significant for all the characters, this suggested that sufficient variability is available in material used for present study.
The mean data were calculated to analysis of variance as per the Randomized Block Design. Analysis of data revealed highly significant differences among genotypes for all traits.
Highest heritability was recorded for grain yield per plant, biological yield and number of tillers per plant, number of panicle per plant and harvest index.
6.2 Conclusion
Combining ability analysis revealed the preponderance of non-additive gene action for all the characters studied. among the lines, IR-82639-115-1 showed positive significant GCA effects was best general combiner for all the characters except days to 50 per cent flowering, panicle length and among the lines, IR-826310-67-2 was best general combiner for tiller number per plant, number of grains per panicle, biological yield, harvest index, grain yield per plant, Among the lines REWA-1103-IR, and IR79971-REWA,IR-82635-47-1,IR-826310-67-2 showed positive significant GCA effects was best general combiner for panicle length, harvest index, grain yield per plant, Among the lines, REWA-1103-IR, , IR-82635-47-1, IR-826310—67-2, and IET-22107, showed positive significant GCA effects was best general combiner number of tillers per plant and biological yield.
Among the testers, the testers, IR-84898-B-168-39, showed positive significant GCA effects was best general combiner for all the characters except plant height, IR-84898-B-168-39, DANTESWARI and CRR-451-193-3-B was best general combiner for, number of grains per panicle, biological yield, grain yield per panicle, Tester IR-84898-B-168-39 was best general combiner for panicle length, harvest index, grain yield per plant, test weight, DANTESWARI was best general combiner for plant height, number of grains per panicle, harvest index.
Hybrid REWA-1103-IR/DANTESWARI, IET-22107/CRR-451-193-3-B IR-82635-47-1/DANTESWARI for number of tillers per plant; REWA-1103-IR/DANTESWARI, IET-22107/CRR-451-193-3-B for number of panicles per; hybrid IET-22107/IR-84898-B-168-39 for panicle length per plant; hybrids REWA-1103-IR/DANTESWARI, IET-22107/CRR-451-193-3-B and IR79971-REWA/IR-84898-B-168-39, IR-82639-115-1/DANTESWARI, IR-826310-67-2/IR-84898-B-168-39 for grain yield per plant number of tiller per plant; REWA-1103-IR/DANTESWARI, IET-22107/CRR-451-193-3-39, IR-79971-REWA/IR-84898-B-168, OM-7938/CR-451-193-3-39, IR-82639-115-1/DANTESWARI, IR-826310-67-2/ R-84898-B-168-39 for biological yield; REWA-1103-IR/CRR-451-193-3-B for harvest index; were found as good specific combiners.
The phenotypic coefficient of variation was higher in magnitude than that of genotypic coefficient of variation for all the characters studied. High genotypic and phenotypic coefficients of variation were recorded for grain yield per plant, harvest index, the moderate estimates genotypic and phenotypic coefficient of variations were observed for tiller number per plant, panicle per plant, genotypic coefficient of variation of harvest index, phenotypic coefficient of variation for number of grains per plant and plant height. The low estimates of genotypic and phenotypic coefficient of variations were recorded for days to 50 per cent flowering, test weight, genotypic coefficient of variation of plant height, panicle length.
The highest heritability were recorded for grain yield per plant, biological yield and number of tillers per plant, number of panicle per plant and harvest index.
The estimates of relative heterosis and heterobeltiosis were also obtained for different characters under study. A high degree of relative heterosis and heterobeltiosis was observed for all the traits. The highest relative heterosis was exhibited by IR-826310-67-2/IR-84898-B-168-39 followed by IVTE/DANTESWARI, IET-22107/CRR-451-193-3-B, highest heterobeltiosis was observed for IR-826310-67-2/IR-84898-B-168-39 followed by IET-22107//IR-84898-B-168-39 However, a high degree of heterosis for other traits in desired direction was also observed.
Grain yield was positive significantly correlated with the, panicle length, number of tillers per plant, biological yield, harvest index and number of panicles per plant.
The study of path analysis of positive direct effects on grain yield showed that harvest index, biological yield, number of grains per plant and number of panicles per plant were most important contributing characters towards the yield, Therefor, the direct selection for harvest index, biological yield, number of grains per plant and number of panicles per plant is likely to be effective in increasing the yield.
6.3 Suggestion for future work
Based on the finding of the present investigations, the following suggestions are being made for future work:
1. Lines, IR-82639-115-1 and IR-826310-67-2 were identified as best general combiners for 50 per cent flowering, panicle length and number tillers per plant, number of grains per panicle and should further be utilized in developing superior hybrids with other source materials also.
2. Testers IR-84898-B-168, DANTESWARI and CRR-451-193-3-B was best general combiner for number of grains per panicle, biological yield, grain yield per panicle were identified as good general combiners for most of the characters and may be utilized in recombination breeding programme to bring in further improvement in respective traits.
3 Non-additive gene action was predominant for grain yield and related traits, which offers scope for exploitation of heterosis.
4 The present investigation revealed that yield is highly positively correlated with the panicle length, number of tillers per plant, biological yield, harvest index and number of panicles per plant and these characters therefore, should be given importance in further selection.
5 The hybrids REWA-1103-IR/DANTESWARI, IET-22107/CRR-451-193-3-B, IR-82635-47-1/DANTESWARI, IR-826310-67-2/IR-84898-B-168-39 showed superior performances and high heterosis for grain yield per plant and therefore, may be recommended for commercial exploitation of heterosis.